High directivity (narrow dispersion) is good for nearfield monitors, in situations where you can't control the overall frequency response of the room. This minimizes the interaction of the monitors with the room (there are less early reflections). On the other hand, the classic large (wall-built, waveguide/horn loaded) monitors in huge control rooms has a wider dispersion, and that means you need better sound treatment in the room. (there is more interaction with the room, due to the greater listening distance and the greater amount of lateral reflections) In general, with wide frec. dispersion, more diffraction treatment is needed (in addition to absorption) Thanks for the content!
I got a full klipsch surround sound with an Onkyo txnr636 with a room that's 9 feet wide and 11feet tall, I just changed from pcm to bitstream and now all of the different listening options sound so insanely good. I've never been able to set my system up properly and my ypao or whatever mic got stolen I had my mains rf82ii's 40 hz, 150m bookshelf speakers were set to 60 and center was set to 60 too ( I'm a bass head....... after changing to bitstream I changed all speakers back to 80hz and then turned down my two subs Idk what the distance should be set for me speakers if my measuring tape says my head's9 feet away do I put it at 9? Should all my speakers are infront of me roughly 4 feet apart for the mains and the book shelf speakers are like a foot apart of the center. I dint have space , should center spread be off and loudness management be on? WHAT SHOULD MY CENTEr image be set to
Please make a video about this. PLEASE. Does anyone know how to adjust the dialogue and background sound? Sometimes the dialogue gets too quite so I turn up the volume. But then the background noise/action scenes gets way too loud, so I turn it down. I find myself constantly adjusting the volume throughout every movie I watch. Thanks!!!
Would you rather be in the recording venue or have the musicians in your room? That's the fundamental difference. I've built both and now use a very wide baffle DIY design (similar to a Sonus Faber Stradavari) and love it.
What are the thoughts on the dispersion of ribbon and pleated tweeters? Do their technology's have it's their own dispersion characteristics or is it still mostly down to any wave guidance that may be utilised?
For direct radiator drivers (no horn or waveguide involved), the dispersion at a given frequency is generally inversely proportional to the diaphragm dimension in that direction. For example, suppose we have a ribbon driver whose diaphragm is 1/2" wide by 6" tall. The horizontal dispersion will be very wide over pretty much its entire spectrum, while the vertical dispersion will be fairly narrow at high frequencies. So if you jump out of your seat to play air guitar, you will lose some of that nice ribbon top end. Anyway in general ribbon and pleated diaphragm tweeters have wide dispersion in the horizontal plane.
Marky M ribbons can and have been made very narrow and as a result we have seen amazingly wide horizontal dispersion in ribbons out to 20khz. Which is highly unusual. However they are long and as such often have narrower vertical dispersion. Pleated drivers such folded motion tend to have somewhat narrower directivity due to their larger size and often have ugly responses at the extreme angles.
@@PoesAcoustics Thank you Matt. I feel blessed to have a response from such a dedicated and passionate expert :-) I am looking at the top 2 tier speaker ranges from the British brand Monitor Audio who have for the past several years used ribbon tweeters and now use pleated tweeters in these ranges. Monitor Audio are found in the US but much more rare. Unfortunately I cannot afford new so I am looking at used pairs which stops me auditioning them in my acoustically challenged 1660 cubic foot square room. I quite often enjoy listening to music while moving around the room doing various tasks and don't always sit around the sweet spot except for when watching movies so I am not sure if these type of tweeters are best for me unless Monitor Audio have done something to help increase the vertical dispersion.
Magnepan, which does not follow the orthodoxy of stereo as strictly as other manufacturers reports that Bell Labs began stereo with three channels, judging it superior to two channel stereo for duplicating an orchestra (where apparently because there large sections of each instrument, might not need pin point imaging if I understand it), but settled for two channels because records could only produce two channels (separated by orthogonal motions of either side of the record grooves). Magnepan did some listener tests using an old Dolby Pro Logic processor which makes the center channel from L+R and plays it at -6 db. Everyone who listened to it preferred the three channels. I request some comments on this. An extra pair of stereo channels can buffer output tubes into one output transformer to a center channel speaker. I like the way it sounds.
Constant directivity vs variable directivity is crucial when assessing room reflections, regardless of the dispersion width. Most cone & dome mids/woofer & tweeters tend to "beam" at the higher end of their range, causing the tonality of their reflections to vary noticeably from the direct sound, whereas the reflections from constant-directivity speakers (omni, line array, horn, waveguide) have the same tonality as the direct sound. Tonally consonant reflections appear as a pleasant, "live" sound, whereas tonally dissonant reflections are unpleasant and detract from the sound quality. Wide dispersion speakers can sound ideal in a "nearfield" configuration, relativity far from the walls, and in acoustically-dampened rooms, whereas the constant-directivity of narrow dispersion speakers such as waveguides or line arrays are ideal in large rooms with live ambience.
Narrow dispersion is great for near field in small rooms and large open spaces (live arena shows or conference facilities with multiple speakers covering specific zones). Moderately wide even dispersion (around 45 degrees left and right of centreline within 3db) is the best in a larger sized domestic settings. The key to good sound is to keep direct and reflected energy balanced across the frequency range. Imaging is most accurate with narrow dispersion and a near seated position - this is simple because reflections are reduced relative to direct sound. However this doesn’t sound natural. Consistent directivity is very important- there should be no bumps in directivity across the crossover. Genelec are wide even dispersion designs with well controlled directivity across the frequency range. ATC or Neumann are also excellent. B&W typically have a discontinuity in directivity at the crossover point between midrange and tweeter (gives the BBC dip or smilie EQ when placed in a room) Small Two way Horns tend to have discontinuity in their crossover region too. Large JBL, Westlakes etc. with large waveguide horns coupled with large woofers and low crossovers points can be even also. Many ways to achieve excellent sound. An analogy is a flashlight vs a floodlight vs a lightbulb. Lighting feels more natural when it is even - it is the same with sound.
Is a Von Schweikert dynamic speaker with multiple drivers and obtains a consistent very wide dispersion with little loss (it has a sweet spot but such a very wide comparable sound) a wide dispersion speaker or a narrow dispersion speaker? I dislike speakers which have very strong narrow dispersion/head in a vise type (25 years ago Martin Logan Monolith III which my wife hated, giant Duntech dynamic speakers, so many others which have narrow sweet spots.
Dispersion is at the very top of the list of importance for professional speakers but often no more than an afterthought for consumer speakers. Ironically it is usually more important in the untreated rooms most of us listen in. Cone drivers have a characteristic dispersion that varies enormously across the frequency range, and that’s not a good thing. A given driver will tend toward omnidirectionality at bass frequencies while exhibiting increasing beaming, or focused lobes of concentrated directivity. These are all negatives for the listener. Recent advances in design and fabrication of horns have allowed exceptionally even dispersion across a wide band of frequencies that no amount of cone drivers can match. The research required to make these is beyond the scope of almost all loudspeaker manufacturers, so we don’t see much of this in home speakers, regardless of price.
Stewart Markley I tend to agree with you that the term waveguide is used excessively and very often to describe what is objectively a horn. The amazingly complex devices manufactured by JBL and Electro Voice that have brought a whole new level of dispersion control to compression drivers are, by anyone’s understanding, horns. I don’t care enough to evangelize on the topic but I don’t need a new name for the very best in horn design.
Stewart Markley Not to harp on about it, but there are many examples of directivity enhancements which can and should be called waveguides as that logically describes what they do. Two different things, two different names.
Thanks for this video. Another brilliant episode wich Matt. What I am always wondering about: How will you know what kind of speakers you have? Asking as most manufactures do not provide any specs in that regard.
That can be a complicated question. It really is too bad that manufacturers don’t provide more information. Traditionally you would use the DI to know this. My suggestion is to to do one of a few things: A) buy speakers you can see measurements on. Reviewers like us take fairly comprehensive measurements on speakers and that provides the info you need. B) in general dome tweeters with no waveguide and all direct radiating midrange or woofers are wide directivity. Panel speakers, waveguide speakers, and driver arrays are often narrow. C) Ask me! I can usually tell by looking at it.
@@makemeinvisible1 Looks like the X38 and X14 are wide dispersion as they are traditional 2-way and 3-way speakers with normal tweeters. Their Confidence 60 and Evidence Platinum beam more due to their design. The video I posted explains it.
Frank Lautenbach yes i agree. The vast majority of tweeters beam at high frequencies. But looking at the average DI and it’s shape, I would expect such a speaker to behave as typical “wide” dispersion speakers. Those BMR’s I showed are an usual exception.
@@mattgiunt yes, took me a while too but result is greater than any other tweak I've tried. Apply RSP to a correctly set up hifi and the real enjoyment of actually listeng to the music takes over.
@@mattgiunt not seen that. I watched the live lecture with Bob and downloaded the pdf. Went from there. It's been about a year now and I havent touched my speakers since.
I got a full klipsch surround sound with an Onkyo txnr636 with a room that's 9 feet wide and 11feet tall, I just changed from pcm to bitstream and now all of the different listening options sound so insanely good. I've never been able to set my system up properly and my ypao or whatever mic got stolen I had my mains rf82ii's 40 hz, 150m bookshelf speakers were set to 60 and center was set to 60 too ( I'm a bass head....... after changing to bitstream I changed all speakers back to 80hz and then turned down my two subs Idk what the distance should be set for me speakers if my measuring tape says my head's9 feet away do I put it at 9? Should all my speakers are infront of me roughly 4 feet apart for the mains and the book shelf speakers are like a foot apart of the center. I dint have space , should center spread be off and loudness management be on? WHAT SHOULD MY CENTEr image be set to
So this backs up the regular advice of always try and compare speakers in your own room before making a purchase. Just remember that once the choice is made never move anything in the room or change any materials and if you move house be prepared to purchase new speakers if the room makeup is very different haha.
For video games at 7.1.4 I would think narrow dis. Speakers are best because then you get headphone or better than headphone pin point accuracy like the devs intended. Watch a movie and 90% of human voice is from center channel. Now play a video game and the person talking spin the camera, the person talking will move with the speakers. My klipsch my not be even close to accurate in a Frequency response but when it comes to pin point accuracy while watching Atmos movies or playing games I think they do absolutly fantastic
i like how you think and hear and it seems like it would be the best, but i also think in real life we dont try to focus on where a sound is coming from( in the real world )so in some ways it would seem to be most realistic to not be able to pin point where a Sound is exactly coming from- it should just sound natural without room reflections ,. also it seems that no center channel should be needed with correct front speaker placement
@@NomadicSociety agreed I just would like to see measurements of a recorded bird play that audio back on a set of surround and see how that turns out. (A difficult task indeed) I am also anti-center channel too I never saw the need for one for most cases, (in a movie theater I could see a benefit as it covers a large area and audience) but in home I no longer buy center channel speakers
What if there is a lack of symmetry in the room? For example no/distant wall on one side and nearby huge window/wall on the other side? In that case wouldn't narrower dispersion and even first reflection absorption on the nearby huge window/wall side to make it less different than the other ("open") side? Also, while you say the absorbers don't have a "flat" response, is that relative to a concrete wall? Drywall? What about a window with drapes?
BTW I caught Gene yawning at around 20:48, but anyways... There's a lot to think about on this subject. Specifically, on dispersion for surrounds, I'd think that, all other considerations like seating area coverage and so on, maybe it makes less difference between "narrow" and "wide" dispersion speaker when you have larger channel count. Because in MC, you are supplying the envelopment in the content, and so the room acoustics are less noticable in general. Also, for a MC system, you might be more likely to have a more damped room anyways, so dispersion differences less audible. For specific spatial cues, like EFX or whatever, I'd think a wide dispersion might be better, just so less chance of localizing to a specific speaker. Again though, the difference might not be so obvious for a high channel count system. I don't really have anything too astute to add, I agree that some more research should be done. Did you have a good look through AES journal papers? If I was at my office, I might be able to find something in my notes or binders.
Todd Welti thanks Todd. I tend to agree. I would favor a narrower dispersion largely only because they also tend to be much higher output. I could make an argument for less room interaction and maintaining more consistent pans but I think it’s all conjecture. I have looked through the literature and couldn’t find anything good. It is my opinion that the level of the DI won’t rise to the level of frequency response issues. So while I feel strongly that DI differences are audibly different, I think that if you blinded people and asked them to choose, they might miss the difference the elevated DI makes in favor of other possible differences. As such I think the study must be done very carefully. I would have two ways to address this: 1) a single speaker with variable dispersion where by the frequency response can be tightly controlled and the tilt of the power response precisely changed through changes in dispersion. 2) a huge sample of speakers with largely varying DI’s but otherwise excellent performance. In other words, a population sampling experiment. In the former you eliminate all other variables that might influence perception. In the latter you simply average it out. The latter is more pragmatic but also less sensitive. Both would use a MUSHRA test interface. That would then be used in Mono, Stereo, and Surround settings don’t the differences can be discerned with each. The surround study would be a very expensive study to complete I would think. If you think of any papers I’ve missed on the topic, let me know. I couldn’t find anything that felt rigorous. It all seemed like generally casual observations. Now Todd, if Lexicon would be willing to loan us a pair SL-1’s I am confident that I could complete such a study! I actually think that is the perfect way to do the study.
Seems to me that one potential issue with surround speakers is that listeners off to the sides are often much closer to the near surround speakers than to the far ones. Todd (or Matt), have you any thoughts about using small J-arrays as surrounds, to reduce this loudness discrepancy?
D L yeah that is an approach suggested for commercial cinemas. Toole talks about it in his book when discussing CBT. I think that for home use we could debate if such an array could be designed to have the coverage angles needed to make that work over such a small distance. It’s easier in a commercial setting. I would argue that regular waveguides would work fine. In fact most decent CD speakers that have relatively wide vertical dispersion or even symmetric dispersion in the horizontal and vertical range could work. With an M2 style, you could lay it o on it’s side. A coaxial could work especially well since they have symmetric directivity. The biggest problem with many coaxials is that they simply don’t have great measured performance. Kef and Genelec make some good ones, but you would ideally want narrower dispersion and higher output than those offer. I have a means to measure this inside so I may give that a shot.
If you can listen to an original pair of Allison speakers in good working condition, you will hear truly wide, evenly distributed dispersion, combined with outstanding imaging.
You didn't mention magneplanar speakers such as the Magnepans (though you touched upon line source speakers). Do I understand correctly that Maggies have a narrow dispersion? (Thinking about it: they should have narrow dispersion in the vertical axis (that is, they reduce reflections from floor and ceiling), but what about the horizontal axis? Cheers, Stefan
I was torn between the golden ear Triton 5's or the SVS Ultras would you guys consider these great speakers at the 2k price point. I really loved the SVS and went with those but only bc no one ever reviews Golde ear and I don't know who Carrie's them. I was only able to physically hear the SVS Ultras? I would really appreciate your thoughts on golden ear Triton 5's. Sometimes I feel those may have been a bit better just not sure. Thanks Gene again without you I'd still be looking for the Moby Dick of towers lol. I went with SVS everything outside of the center which is Martin Logan motion8i😁!
You are right I totally should have mentioned that. Yes planar and electrostatic panel speakers have such wide diaphragms that they inherently have very narrow directivity. Much narrower a than a throng I showed.
Excellent stuff guys, especially for us newbies. Thank you! Matt, I may have heard you wrong but, in commenting on the B&W polar plot, I thought I heard you say it’s impossible to cross a 1” dome tweeter w/ a 6-1/2” mid bass driver well. So many 2 ways are configured this way, and you mentioned in the last video that the M126be is one of your favorites. Did I hear you wrong or miss something? Thanks again.
I think it's a fine approach. A larger midrange 6 to 7 inches (maybe even 8) will definitely beam frequencies in the range of 2khz to 4khz. That's good in my opinion. They cause listening fatigue since they resonate in your ear canal. Reducing these frequencies off axis will reduce reflections. Now you only have these harsh frequencies hitting you directly and don't get reinforcement from side wall reflections. No complaints from me.
Worth mentioning I don't agree with Matt's assertion that Genelec are narrow directivity speakers. Genelec's coaxial The One's have ~65 degree dispersion which is in fact wider than Revel's Performa series (~60 degrees), which he categorizes as "wide dispersion"
Derelict Music a few thoughts. The Genelecs that with the coax that I am looking at have a power response DI of 8dB or so above 1khz. The Revel is 6dB. So I am not sure where you are getting your numbers but from what I see, the Genelec has narrower dispersion. Second and more importantly, I State in the video that the narrow vs wide is a continuum and now a hard separation. I establish rough criteria and go with that, but certainly the revel and Genelec fall on either side of an arbitrary line in the spectrum.
I am surprised that the JBL M2 would fall into the narrow dispersion catagory. These are the flagship speakers for Sean Olive and HK. The very folks who have touted wide dispersion speaker designs.
I see that you have Revel M126Be and M16 on your recommendation for wide dispersion. Doesnt they have waveguides? and shouldnt they be narrow dispersion? btw, thanks for this awesome video
They both have a DI under 6 so I’m calling them wide. A waveguide doesn’t automatically mean narrow. But as I said in the video, it’s a continuum, not a hard divide. They are in-between.
hmm, so with acoustic absorbers, is it fair to say that DIY is always best? So for example the vertical decay is know at differing degrees, if you measure at which point of the wall that degree would hit the wall, a section of the absorber acan be reinforced with denser or less dense absorption material. By doing so you can better acheive a flatter consistent level of absorption. Same with dispersion acoustic treatment id say. If its wide dispersion speakers and theres too much decay once it hits the wall, best to not place the diffuser any where there. Damn, this rabbit hole just gets more complexed. Someone let me know if I got this wrong. Im lookijng to get full range woofers as my first DIY speaker and the Voice induction is super low, indicating beaming. is beaming a stronger form of Low dispersion?
I'm really curious what speakers Matt would like more between the Revel f208's and the new JBL HD's that were mentioned. Those are the two that i'm currently looking at. I currently have the Klipsch RP-8000F's (Great speakers) but i'm looking to upgrade, hopefully for the last time, LOL. Thoughts?...
Fellow audiophiles an OT. How loud do you listen to your music from you speakers in DB. I do 55-60 db is loud enough for my ears. How about yours. To measure it if you have not sound meter gear use your smartphones as the kit by downloading the app sound meter from the app store.
It all depends on the size of your room, the sensitivity of your speakers and the capability of your amplifier. My room is small & low ceiling with 90db sensitivity bookshelf speakers with a 30hz low frequency bass. A very high quality transparent 100w each channel stereo power amplifier. I rarely turn the volume dial of my amplifier up over half way. Smaller rooms can sound amazing, are easier to work with and cost less on speakers, amplifiers etc.
What matters much more than wide vs narrow is constant directivity as per Floyd Toole's research at Harmann: response must be flat (lower level than on axis is allowed) under each angle off axis (360 deg) which implies a flat power response . You can attain that only with dipoles (Linkwitz LX531) which is narrow , omnipoles like the MLB's which are extremely wide , or cardioid like Kii Thee which are in between. Normal classic monopole boxes nearly never have anything close to constant directivity
Gerrit Govaerts you have some of your facts wrong. Floyd work never suggested a flat power response was desirable. Quite the opposite. The power response should be tilted. His work and that of Sean Olive has favored monopoles more than omnipoles. Constant directivity can be achieved with many design approaches. The BMR’s have even dispersion out to 90 degrees of either side with almost no fall off. It’s the lowest DI of any monopole we have ever measured. It would follow what you describe. My speakers use waveguides and large drivers. It has a fairly high DI. It literally Meets Keele’s definition of constant directivity as he defined in the EV patent. In fact that is an important point. CD has a definition as it was a term coined in both a paper and patent. As such, the only definition we can use is that definition. products.electrovoice.com/binary/EV_PABible-07-Add06-Constant_Directivity_White_Horn_Paper-1980.pdf But you are not the first to misuse the term and even I find it a little confusing. The alternative term of controlled directivity usually requires that a speaker have a device that controls the directivity rather than allowing it to be as wide as possible. It also doesn’t necessarily imply constant directivity in the pejorative sense. The vast majority of true constant directivity speakers are monopoles as most of them are pro audio. The term refers to having the same directivity over a wide range of frequencies. It does mean the same amplitude over a wide range of frequencies. In theory a perfect CD speaker would have a flat DI down to 20hz and up to 20khz. However it is not generally considered necessary to achieve such wide bandwidth constant directivity. I address all of this accurately in this and the last video. Dipoles do not have a flat power response. Go lookup the definition of a dipole. It seems you saw that sound radiates out both sides of the speaker and assumed that meant 360 degree coverage. That isn’t what it means. A dipole design cancels sound to the sides causing mills which reduce sidewalk reflections. They still have strong rear and front coverage however. Such a design could meet the criteria of CD but few do. I would argue that Linkwitz designs don’t really. The Kii is like a more extreme version of the waveguide speakers I mentioned. Via beam steering they cancel sound radiating to the back and sides to create a flat extended DI. They are the definition of a monopole as their love is completely forward facing. Unlike normal monopoles which radiate as omni in the bass, they radiate very little to the rear. Hence cardioid.
@@PoesAcoustics Look , we can argue about the definition of constant directivity all day long , but I am a simple guy and for me it means what it intuitively implies . No matter from wich direction you measure the response , it's the same response , allbeit lower or higher in volume and prefferably (not necessarilly) flat from every angle . That way , the tonality of the speaker is identical and neutral in every direction , implying I am hearing the same song from both direct and indirect sound , which should have some psycho-acoustical benefits I guess. I cannot imagine any normal monopole (exluding cardioids) with a normal baffle size being truely Constant Directivity (in my understanding of CD) : wavelengths of more than a meter under 300 Hz and longer will easily warp around the baffle , creating an omnipole dispersion . Either you follow that up with a monopole dispersion in mids and highs or you loose CD . That seems logic to me . It also seems logic to me that if you have constant directivity throughout the whole audio frequency band AND a flat frequency response , you will automatically have a flat power response . Where is the flaw in my reasoning ? I think I have a good understanding of what a dipole is , including the physics and math involved (see link to pdf) . I agree however that Linkwitz designs (certainly the early ones ) are not true CD . That does not mean that true CD dipoles do not exist or cannot be built or designed . You just have to know how to do that . You will need a 3 or better 4 way system and dimension your drivers in coordination with your crossover point . For mids and highs this will need to be a naked no-baffle design in order for a high enough first dipole peak (drivers + baffle need to be as narrow as possible , hence no baffle) . Bass can use an H-frame for adequate dipole distance . By crossing drivers before they reach the first dipole peak (and using lotsa EQ) , you can ensure that each driver creates a perfect and constant figure of 8 dispersion , thus CD . The whole theory of dipoles and how to create CD dipoles with a no-baffle naked approach can be found here : www.dipolplus.de/thema11.php . Highly recommended . And before you ask , yes I made a 3 way CD dipole for which I have measurements that prove CD in the horizontal plane from 20 Hz up to 10 Khz : 2 x 12 inch in H-frame with 480 mm dipole distance crossed at 340 Hz to 2x 5 inch mids crossed at 1700 Hz to a dipole AMT tweeter from Mundorf . I normally do not consider cardioids to be monopoles as they can arise from a dipole in a U-frame, but I can see how you could. On Floyd's research,IIRC the number one characteristic needed for high quality sound reproduction that everybody agreed upon by far was constant directivity (not necessarily flat power response , I agree) . My own experience backs that up . I toyed with classic monopoles for decades and never got a really satisfying sound image until I started building omni's and CD dipoles . There is no going back for me
Gerrit Govaerts as I’ve said to others, I can’t and won’t use different definitions because someone wants to use the term differently. You have much of the deformity correct, but you seem to assume this must be achieved over 360 degrees. You cited Toole as proof of this requirement. He has said no such thing and the highest scoring speakers in Harmans testing have largely been monopoles. You are right, a monopole won’t maintain the same shaped response around 360 degrees, while mid and high frequencies do still radiate backwards, it’s typically at a much lower level. But that I can only say, what’s the problem? A speaker is meant to be placed out into a room but still largely near boundaries. Often within 3-6 feet. Some people place them even closer. Why would we need to have strong reflections off the front wall to achieve more consistent sound? If anything, I would want to avoid front wall reflections. It is lateral reflections which are the most important to achieving enhanced ASW. Even spaciousness is more important coming from the side and back wall than the front. So why is it that you believe that even dispersion out the back of the speaker is so critical? I think the term you need to coin here maybe is consistent directivity. As I said, constant and controlled directivity are terms that have been defined and widely used. Neither would include omni-directional speakers. As for research on this topic: there is virtually no research investigating speakers which radiate evenly in 360 degrees. There is a bit of research that looked at monopoles vs dipoles but as I said, they don’t have an even response to the sisters. They have quite narrow directivity toward the front and back. Most of the work really was either poor in quality or inconclusive. The strongest findings in any of the studies concluded that untrained listeners seem to prefer wider dispersion, trained listeners seemed to prefer narrower dispersion, wider dispersion speakers tended to score slightly higher at Harman but this was never an explicit test, narrower directivity was preferred in multichannel systems (which makes sense since the surround speakers now give all those spatial cues and do so far more accurately).
@@PoesAcoustics Ok , I can agree on using consistent directivity , but the use of 'constant' is at least a bit misleading if it does not imply 360 deg. So why do I insist on consistent ? Well , basically bc I think it can't be a bad thing if all my indirect sound (including that from the front wall) sounds the same as my direct sound . If it does not sound the same , isn't that worse ? Does that not require my brain to make corrections for correct interpretation , taking away brain cpu power that is needed for creating the spatial image ? (Removing a subwoofer is such a example , where instead of missing the bass tones , you really loose imaging while your brain is reconstructing the missing base by using the harmonics) . In my experience , it does . I just cannot wrap my head around the fact that for my brain some indirect sound is less relevant than other indirect sound (and which would that be, and why ?) . Siegfried Linkwitz agrees with me : " The ear drum signals also contain cues about the room, though colored in the case of a loudspeaker that radiates a different spectrum in different directions. It has been my observation that a spatially more open and 3-dimensional auditory scene is created in one's mind when the loudspeakers radiate uniformly in all directions like dipoles or omnis do. The auditory scene has great clarity and distance but not the hard edges and closeness that a highly directional loudspeaker tends to produce" . TBH , he also added : "I do not know how consistent the radiation pattern has to be. Nor do I know that constant directivity over the whole frequency range is optimum" But if Floyd did not mean 360 deg in using the term CD , then I stand corrected . Anyway you define it , CD is in my experience the most important characteristic of what makes a loudspeaker sound good , and way beyond any other measurement
Gerrit Govaerts I get where you are coming from. However I think what you want can be achieved just fine without having a speaker have 360 radiation. The ear/brains ability to discern the tonality and individuality of reflections is restricted to well above the modal zone of a room. Geddes has defined that as 500hz and in conversations with Floyd about this, be too basically says somewhere in that range. Say 300 to 500hz. What that means is that the sound radiating omnidirectionally below 500hz is not likely perceived as causing a colored reflection. What you are saying is basically true but I see it mostly discussed in the context of first reflection points off the sidewalks, back wall, and to some extent floor and ceiling. Really the only area of disagreement is going to be first reflections off the front wall. The way my CD monopoles measure would lead to front wall reflections which simply combine with the bass range and add nothing in terms of mid/high spatial cues off that wall. I think the bigger benefit of speakers as you describe is that they dramatically increase the ratio of reflected to direct sound and this provided a much larger and more spacious sounding image. At the expensive of image specificity. I think it is quite debatable which is preferable and find no surprise that the research on preference is inconclusive. Most experts who prefer wide dispersion rightly point out that precise imaging is not a real thing with real performances. The counter argument that Geddes and I use is that it IS a real thing with studio mastered music. The latter is a scenario where the musical performance is artificial. It never existed in real life as it does on that recording. That is a musical experience made up in the minds of the engineer and artists. As such, what they heard (which nearly always uses reflection free mixing and a very high direct to reflected ratio) is probably the closest we can come to reality. I happen to prefer that more direct sound but fully recognize that it is neither right nor wrong. It’s just a preference. As I said in the video, I’ve heard plenty of wide and even very wide dispersion speakers that I loved. Some that I would happily own. And...if I were a rich man, I would happily have more than one system, one of which would use a very wide dispersion Speaker Capable of 360 degree dispersion and place them in a large and largely reflective room. Why? I’ve heard it before and for certain types of music I found it really enjoyable. I too think CD is the most important factor in speaker design I just define it slightly differently than you.
Question: clipping kills tweeters because of the added HF component of the clipping, correct? Does bi-amping avoid that problem, since its likely the clipping will happen first on the woofer amp.
Don't use a underpowered or overpowered amplifier for your speakers. Problem solved 👌🏾 If your turning the volume dial of the amplifier all the way to the max and hear clipping then lower the volume 👍🏾
You can get both good wide dispersion and narrow dispersion speakers. But you need to carefully research wide dispersion speakers as lot's are poorly designed implemented. My centre (it's called centre here in the UK) channel is a properly well implemented wide dispersion speaker. The advantages are explosions, crashes, action scenes etc from the centre channel have a 3D holographic like effect. More natural realistic than a narrow dispersion speaker. Ie a explosion in real life beams sound in all directions, not just a narrow beam of sound.
Awesome video series, thank you guys! Do you feel narrow or wide dispersion speakers would have an advantage in the following scenario? 1/ listening to music only 2/ untreated medium to large living room with hardwood floor (probably quite a few reflections) 3/ music may be listened to in several locations in the living room (sitting or standing) 4/ any attentive listening is done sitting on a couch turned 90 degrees relative to the plane of the speakers 5/ speakers near walls / corners Wide dispersion could be perceived as having an advantage for points 1 to 3, while narrow dispersion speakers may be more suited for points 4 and 5...
1) what is your goal for soundstage? How far apart of the speakers and how far apart are you? 2)Get some sound diffusers and absorbers. These can had cheaply or made even cheaper and can be done in an artistic fashion for the Mrs. This will make the BIGGEST DIFFERENCE. Use a mirror from the seating position and find your reflection points. 3) Surround sound an option? IF not, this will lend to needing wide dispersion. 4) Tow your speakers a little, shouldn't be 90 degrees. Tow in until you get a phantom center 5) Depends on the speaker. Klipsch CornWall? Put in a corner or near a wall. Point is, every speaker will be different and especially when you consider room gain. Need to tinker with the placement to get it right.
Good treatment guys on dispersion and it's perception. One comment though on your use of the term waveguides. In all of your references to waveguides, you are actually referring to horns. Horns and waveguides are similar but different. Horns actually accomplish two things. Besides guiding waves, horns act as a acoustic transformer because of their flare. Waveguides only direct waves. The only use of waveguides in speakers is a transmission line which has no flare. No one would use a waveguide in the front of a speaker unless they wanted an extremely narrow dispersion pattern. The use of the term waveguides to describe horns is incorrect and misleading.
We are not incorrect in how we used it. I use it consistently with the man who defined the difference. Earl Geddes. The depth of the “horns” in question is far too shallow to provide the acoustic loading you speak of and are all considered waveguides per the definition be defined. Since he has reviewed much of this before I am confident he would agree.
@@PoesAcoustics Simple answer. Remove the driver from the waveguide and find out if there is a level difference. If there is, it's a horn. Waveguides do not match impedances.
Stewart Markley that’s incorrect and Geddes will not agree with you on this statement. www.gedlee.com/Papers/What%20is%20a%20Waveguide.pdf It’s his definition. If you disagree with him I suggest you take it up with him or publish your refutation of his definition.
@@PoesAcoustics I've read the papers you've referenced and while Mr. Geddes has done fine work, the differences in the terminologies is because of the primary objective differences between his efforts and that of Webster. Webster was focused on the objective of loading and impedance matching while this was ignored by Mr. Geddes because as he stated the aspect of efficiency was not important because solid state amplification provided plenty of power so his focus was on the aspect of directivity. Horn theory is a special case of waveguide theory which is more generalized. Einstein also had a special case of the theory of relativity but he called it the Special Theory of Relativity and then the generalized theory he called the General Theory of Relativity. He did not change the name even though the focus of the special theory was on relative motion while the focus of the general theory was on gravitational effects on light which also blossomed into energy and mass relationships and space/time relationships. Mr. Geddes states in his What is a Waveguide paper "The equations that I used are completely different than the Horn Equation, so in a very real sense what I had developed were not “horns” as Webster was thinking about them. On the other hand they are indeed horns in the sense that a horn is any conduit of varying cross section (basically anything is a horn under this definition). I do not agree that anything is a horn, for example acoustic transmission lines or microwave waveguides are not horns because they do not have a varying cross section, which he just stated that a horn has a varying cross section. In the end, all waveguides of varying cross sections like we see on loudspeakers have both properties of impedance matching/loading and controlling the direction of sound. I do not see a need to change the original terminology just because of a later more generalized and different objectives of study. Horns are not bad, and waveguides are not bad, they just have different objectives which overlap in realization.
Great video guys, many thanks. Just on the off-chance would you know the ProAc Tablette 10 Signature small bookshelf speakers and if they are wide or narrow dispersion? Basically, I have a very small listening room (with near-field listening) and have been forced to re-consider my speaker options due to worries about boomy bass and placement issues in a small non-treated room. The ProAc Tablettes are sealed speakers and can be placed near to the side/back walls with less problems. I assume narrow dispersion would be better in this set-up? Would be so grateful for some advice...thank you.
@@PoesAcoustics Thanks Matthew. I am trying to choose some standmounters for my small listening room. The electronics part seems fairly easy in comparison but finding the right bookshelf speakers is challenging for a small, non-optimal room. I am strongly considering room correction as a first option (and possibly some minor acoustic treatment). If I contacted you/Gene at a later date, would you be open to helping me with this on a consultancy basis? Hoping you will say yes!
Marc Foss yes. Contact me through Poesacoustics(at)gmail.com. Eventually this will be something we can offer right through the Audioholics website but for now you can contact me directly. I have various consulting packages depending on your needs.
@@PoesAcoustics Thank you. It may not be for a while as I still have to purchase my music system and move into the new apartment/listening room, but I definitely look forward to being in contact.
Truly excellent video, thank you both for your time and effort and expertise in making it. Congrats Matt on owning the GedLee Abbeys. You taught me something I didn't realize: That absorption affects the frequency spectrum of specific individual reflections differently depending on their angle of incidence. Thank you! Matt, in your opinion, what are the acoustic/psychoacoustic mechanisms which give rise to greater apparent source width (ASW) for wide-pattern speakers? I am under the impression that early same-side-wall reflections contribute, which implies that the Haas effect isn't 100% effective. But I may be mistaken, and/or unaware of other factors. Thanks!
@@PoesAcoustics In your video "Optimizing Small Room Acoustics", at 31:10 to 31:55, you talk about early sidewall reflections being like a mirror image reflection of the speaker's output, and say that it "tends to smear the soundstage. " I agree with you. So here is my question: Is this "smearing of the soundstage" from this early sidewall reflection PART OF what creates Toole's "apparent source width", which wide dispersion speakers have more of? Or am I confused, and they are two different things? Thanks!
D L hi DL, I wasn’t talking about that but it is the same thing. ASW our apparent source width is caused by lateral reflections and gives us the perception of width. Our auditory system is not fast enough to perceive those lateral reflections as discrete. As such the brain integrates them and it forms a widening or smearing of the image. This is typically a desirable thing but in the example I was giving, I was suggesting that particular form of widening would be undesirable. Those very early lateral reflections also cause a lot of comb filtering which messes up the response and causes colorations. It also smears the image in a more unnatural way. When a speaker is placed right against a wall the reflections are so early that while they do cause a widening/smearing perceived as ASW, it’s not how we would hear such a thing if this was a real performance space. That is why you generally would prefer speakers farther from the side walls. At least a little gap is desirable to increase ASW sufficiently and in a more desirable way. Of course another argument is we are all wet here and ASW is being misused in this context. It’s origins and majority of research has been in large symphonic halls, not homes. There are studies of small acoustic spaces to test hearing aid DSP and this gives us clues that the ASW effect remains present in small rooms and by 2 speakers. We also have anechoic chamber studies that show how it works even when the reflections are short. From that I like to think it all applies still just fine. But I know many of the measures like IACC tend to get messier in small rooms. I do binaural impulse measurements of rooms and calculate IACC sometimes and find the value fluctuates in strange ways in small rooms. Something I never had seen in large acoustic spaces before. There are also no standards to assess a small rooms quality based on its IACC due to a lack of research in this.
@@PoesAcoustics Thank you very much Matt for taking the time to reply in depth. I'm still a little confused as to the relationship between the Haas effect and apparent source width from lateral reflections, as they seem to both be in play at the same time. Maybe I'm misusing the term "apparent source width", as I have been thinking of it in terms of "how wide the soundstage seems to be" but not in terms of "spaciousness" and "envelopment". If I understand him correctly, Geddes finds that the early same-side-wall reflection is particularly detrimental, but can be essentially avoided with controlled directivity and aggressive toe-in. This results in the first significant lateral reflection of the left-hand speaker being the across-the-room bounce off the right-hand wall (and vice-versa), and because it arrives at the opposite ear from the first-arrival sound, the ear can process it as discrete. In his room his left and right main speakers are very close to the side walls, and toed in maybe 45 degrees. At any rate Geddes advocates minimizing reflections arriving within 10 milliseconds of the direct sound, and my experience with a fairly wide range of dispersion patterns (including dipole, bipole, and other polydirectionals) agrees with that. Linkiwitz suggested 6 milliseconds, but ime there is worthwhile benefit from pushing it back to 10 milliseconds. By the way I absolutely love something you said in that "Small Room Acoustics" video: “A speaker that has controlled dispersion does basically the same thing you'd expect an acoustic panel to do, but it does a better job. And it allows you to get away with no panels on the wall.” Wish I'd been following these videos you've been making with Gene from the beginning. Just found you recently, so making up for lost time as I'm able to.
D L well so the HAAS effect is the psychoacoustical name for the precedence effect that I noted here. The first arriving sound dominates over the latter sound. The later reflection still impacts how we perceive the location of the sound source but is drowned out by the first arriving sound. So with that in mind, ASW is the widening of the sound image caused by those secondary lateral reflections. With binaural hearing, if the brain receives two equally spaced and timed direct sound waves and two equally spaced and delayed secondary waves it perceived that as one tone. It integrates them. But the secondary tones have the effect of widening the image. Haas actually goes into great detail of this including ASW. I would argue that maybe saying Geddes is advocating for 10ms is putting words in his mouth. He states in his paper on ideal speaker directivity that
Thanks so much for this. Coming here from the SBIR discussion, and seeing you've adressed some of the issues I'm trying to wrap my head around. Your whole channel is a gold mine. A thought on the narrow dispersion for studio recordings vs. wide dispersion for live recordings/classical. Might this also be a question about the character of the music itself? I've heard rock bands live in very reverberant environments. Doesn't work. I've heard acoustic percussionists in reverberant environments, doesn't work. I've heard choirs in churches, boy does that work. Brass bands playing christmas carols, the same. The roles played by legato vs. staccato, bowed strings vs. pizzicato. From one extreme of church organs, voices and similar expressions with big chords and a flowing character, to the other of percussionists, drummers, palm muted strings with strong transients in rytmhically dense and complex works. I would assume it influences how the music is recorded and mixed, and how we want it reproduced. It even gets me to thinking of how acoustic environments have influenced what kind of musical expressions are created under various circumstances (and recommend reading David Byrne/ How music works).
I don't see how any speakers can cover a "few seats" off axis of the sweet spot and still deliver the center imaging. The center image is created by balanced sound coming from right and left speaker. Maybe you are referring to HT, but music is more nuanced. If I tilt my head to the left, the image moves a bit to the left.
I discussed it in this video and will go into it extensively in the next video. The concept is called time intensity trading. We hear these phantom images or any image placement based on either the delay in the response to one ear vs the other or the difference in level. What is known as the Interaural Time Difference (ITD) and Interaural intensity Difference (IID). When the brain receives conflicting information it will use intensity over timing information and discard the timing difference. What that means is that a center image is typically created due to a balance of ITD and IID when you are centered between the speakers. However, you can take advantage of the brains time intensity trading phenomena by using a speaker that has carefully controlled dispersion. Because that speaker will get quieter as you move off axis, you can aim them such that as you move to the side, the farther speaker gets louder and the nearer speaker gets quieter. The brain discards they timing difference and maintains a solid center image. This phenomena as used with speakers has been written up a few times and the phenomena itself is a well known psychoacoustics property. In fact it takes on a different set of characteristics at low frequencies (where by we perceive longer LF tones as being louder). Here is a link to a primer on the topic and my presentation will go farther to explaining this. www.libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf
Dr. Toole's work is excellent in many respects but I do not share the idea that early reflections are beneficial in most music in rooms. I recently heard a stunning example of the benefit of early reflections when Josh Groban was singing in his shower and it sounded much better than when singing in his living room. But when he started just talking in the shower, it was immediately evident how hard it was to understand what he was saying. This demonstrates that the brain considers early reflections with a solo singer (a simple sound source) to be more enjoyable when it is not trying to resolve fine details in the sound, but when it is trying to resolve fine details as in comprehending speech, it is difficult and not enjoyable. This means that for music which is complex (which means most music), we do not want to have early reflections which confuse the brain and make it difficult to resolve details. That's my two cents.
I haven’t measured them myself but that is my understanding and theoretically it makes sense. I have measured larger drivers and panel drivers such as large folded motion or planar drivers. I haven’t had the chance to measure an entire ML electrostat or similar. I’d like to some day. Here is how I understand they measure: they have a dipole radiation pattern with a pinching of the dispersion to the sides where the sound wrapping around the front and back self-interferes and cancels the side radiation. The very wide panel leads to a very focused narrow pattern and the treble beams heavily. The dispersion pattern would look a bit more like a triangle. ML curves the panel to address this dispersion problem and that helps to reduce the beaming, widen dispersion a bit, while still avoiding strong sidewall reflections. Which is all to say that yes they shouldn’t have overly strong reflections to the side. Now having said that, I had a client recently with on-wall ML electrostat speakers. One of them was placed near an object and appeared to be interacting with it. The reason for this was a design problem (and if I were ML I know how I would have fixed it). If you place a typical cardio for dipole radiator against a wall it becomes a monopole. It’s very likely that the midrange and low frequencies were still projecting strongly to the side which is exactly what we saw in a beat pattern in the measurements.
@@PoesAcoustics Thanks. I'm actually considering an all-electrostat ML surround setup, using the on-wall speakers for the surrounds. I won't have objects near the surrounds, but should I be concerned otherwise? Did that client's setup end up sounding good?
Sendu Bala he is still purchasing treatments. We did a test where by he grabbed a lot of pillows and blankets and used them as temporary treatments. I really had him do this to see what was causing what. However he did indicate the sound improving. I personally believe that a dipole radiator like this against a wall isn’t a great idea. However if you want the best channel to channel consistency it is your only option. What I would probably do is consider mounting them onto an absorber and having an absorber around them if need be.
there should be a gap between the absorption panels a 6 inch gap where the tweeter would lie inline at the first reflection point and at the listening point there should be a 12-inch gap and you want the panels to go behind the speakers not just in front. You want your panels to be away from the wall to catch the deflection bounce back a good materials natural wool fleece just hang it an inch or so away from the wall The Mbl could be directional if you put two side baffles splitting off between the dispersion from the back and front, the more you slope them more directional they would become. In the future can you mark on the pictures what speaker you talking about! because I can't tell by the picture what speaker you are representing, I'm assuming left to right top to bottom. Turn your mic gain down a little bit down it is over stretching it's parameters getting echoing from your room and sounds like the EQ is a little bit high in the mid to hide turn down a bit Gene
Which one of us was too high? Which one had too much midrange. Gene or me? While what you say is essentially true for the MBL, why would you. The entire point of that speakers unique driver design is to provide an even flat power response. There are better monopoles if that is what you want. I’m not really sure what you are saying about the panels. A 6” to 12” gap would be pretty large for most people. In fact 12” is on the verge of the panel not interacting with the wall behind it in a predictable way. It usually would lead to a lot of wobbles in the absorption response. A gap is good but 12” is extreme. If 12” is what you want I would suggest designing the absorber for that purpose. In my room the curved panels are Vicoustic panels at about 2”-2.5” thick and sitting on a 1x3” frame. That frame is filled with a bonded cotton insulation. It has the equivalent absorption of a typical 6” thick panel. Those blue free standing panels can’t be placed any closer than 2” from the wall due to the feet. The panel is about 4.5” thick and filled with a core of 8” mineral wool. It’s 4.5” thick on the bottom half and 2” on the top. The rest of the top has that same cotton bonded insulation which has better high frequency absorption. People can’t see the rest of the treatments in the room Because they are all hidden in some way. The walls articulate and are highly damped CLD. The front wall and front 30” of the side walls and ceiling have 4” of fiberglass bonded insulation with a film diaphragm layered at 2”. The corners have bass traps made from 6# insulation. The ceiling also has another 2.5” MLS diffuser/absorber that extends over 48” out from the screen and covers the first reflection point. The rooms acoustics turned out so good that I use its measured result as my example to customers of what we target. Since few customers let me go this far with their rooms I have my own room and just two others I can use examples of near perfection.
Wow... so much misinformation in this it's hard to know where to start. All the data I know of from AES papers yeild the same result - speakers with Wide smooth frequency response is prefered by listeners in blind trial again and again...
Best Damn Channel on Everything Home Audio! Thank you guys and great to see you feeling better Gene👍
This gentleman is exceptionally knowledgeable and articulate on this subject.As an audio enthusiast for over 50 years I am truly impressed.
Best explanation on this topic to date. Thank you Gene and Matt for giving so much of your time and expertise back to the community.
Matt is low key and very matter of fact. Just the guy you need to walk you through the audio minefield.
High directivity (narrow dispersion) is good for nearfield monitors, in situations where you can't control the overall frequency response of the room. This minimizes the interaction of the monitors with the room (there are less early reflections).
On the other hand, the classic large (wall-built, waveguide/horn loaded) monitors in huge control rooms has a wider dispersion, and that means you need better sound treatment in the room. (there is more interaction with the room, due to the greater listening distance and the greater amount of lateral reflections)
In general, with wide frec. dispersion, more diffraction treatment is needed (in addition to absorption)
Thanks for the content!
Great video guys! Loved the one on polar plots too.
Matt is back again!
I respect Matt. He doesn't care if he's going to upset us, just tells it like it is!
I was crying when he let me know my $300,000 speaker is for the birds
The time intensity trading made a huge difference on my Klipsch RP8000Fs! The evenness throughout the room was much better!
I got a full klipsch surround sound with an Onkyo txnr636 with a room that's 9 feet wide and 11feet tall, I just changed from pcm to bitstream and now all of the different listening options sound so insanely good. I've never been able to set my system up properly and my ypao or whatever mic got stolen I had my mains rf82ii's 40 hz, 150m bookshelf speakers were set to 60 and center was set to 60 too ( I'm a bass head....... after changing to bitstream I changed all speakers back to 80hz and then turned down my two subs
Idk what the distance should be set for me speakers if my measuring tape says my head's9 feet away do I put it at 9?
Should all my speakers are infront of me roughly 4 feet apart for the mains and the book shelf speakers are like a foot apart of the center. I dint have space , should center spread be off and loudness management be on?
WHAT SHOULD MY CENTEr image be set to
That’s one of the most interesting materials that I’ve heard lately! Thank you guys!
Great video!! Learned lots, thanks! Look forward to the next
Please make a video about this. PLEASE. Does anyone know how to adjust the dialogue and background sound? Sometimes the dialogue gets too quite so I turn up the volume. But then the background noise/action scenes gets way too loud, so I turn it down. I find myself constantly adjusting the volume throughout every movie I watch. Thanks!!!
This really would be a good subject to discuss. I will see if I can persuade these guys to tackle this subject...
Need to add the JBL Studio 590's...very wide dispersion for a compression horn driver...
Love my Elac unifi B5’s. Was watching Thor las night. When he dropped his coffee cup it sounded like it hit my floor. It made me look down
Would you rather be in the recording venue or have the musicians in your room? That's the fundamental difference. I've built both and now use a very wide baffle DIY design (similar to a Sonus Faber Stradavari) and love it.
What are the thoughts on the dispersion of ribbon and pleated tweeters? Do their technology's have it's their own dispersion characteristics or is it still mostly down to any wave guidance that may be utilised?
For direct radiator drivers (no horn or waveguide involved), the dispersion at a given frequency is generally inversely proportional to the diaphragm dimension in that direction. For example, suppose we have a ribbon driver whose diaphragm is 1/2" wide by 6" tall. The horizontal dispersion will be very wide over pretty much its entire spectrum, while the vertical dispersion will be fairly narrow at high frequencies. So if you jump out of your seat to play air guitar, you will lose some of that nice ribbon top end. Anyway in general ribbon and pleated diaphragm tweeters have wide dispersion in the horizontal plane.
Marky M ribbons can and have been made very narrow and as a result we have seen amazingly wide horizontal dispersion in ribbons out to 20khz. Which is highly unusual. However they are long and as such often have narrower vertical dispersion.
Pleated drivers such folded motion tend to have somewhat narrower directivity due to their larger size and often have ugly responses at the extreme angles.
@@PoesAcoustics Thank you Matt. I feel blessed to have a response from such a dedicated and passionate expert :-) I am looking at the top 2 tier speaker ranges from the British brand Monitor Audio who have for the past several years used ribbon tweeters and now use pleated tweeters in these ranges. Monitor Audio are found in the US but much more rare. Unfortunately I cannot afford new so I am looking at used pairs which stops me auditioning them in my acoustically challenged 1660 cubic foot square room. I quite often enjoy listening to music while moving around the room doing various tasks and don't always sit around the sweet spot except for when watching movies so I am not sure if these type of tweeters are best for me unless Monitor Audio have done something to help increase the vertical dispersion.
@@dl6519 Thank you D L. I like your 'air guitar' analogy. This type of tweeter may not be for me then.
Magnepan, which does not follow the orthodoxy of stereo as strictly as other manufacturers reports that Bell Labs began stereo with three channels, judging it superior to two channel stereo for duplicating an orchestra (where apparently because there large sections of each instrument, might not need pin point imaging if I understand it), but settled for two channels because records could only produce two channels (separated by orthogonal motions of either side of the record grooves). Magnepan did some listener tests using an old Dolby Pro Logic processor which makes the center channel from L+R and plays it at -6 db. Everyone who listened to it preferred the three channels. I request some comments on this. An extra pair of stereo channels can buffer output tubes into one output transformer to a center channel speaker. I like the way it sounds.
Constant directivity vs variable directivity is crucial when assessing room reflections, regardless of the dispersion width. Most cone & dome mids/woofer & tweeters tend to "beam" at the higher end of their range, causing the tonality of their reflections to vary noticeably from the direct sound, whereas the reflections from constant-directivity speakers (omni, line array, horn, waveguide) have the same tonality as the direct sound. Tonally consonant reflections appear as a pleasant, "live" sound, whereas tonally dissonant reflections are unpleasant and detract from the sound quality.
Wide dispersion speakers can sound ideal in a "nearfield" configuration, relativity far from the walls, and in acoustically-dampened rooms, whereas the constant-directivity of narrow dispersion speakers such as waveguides or line arrays are ideal in large rooms with live ambience.
Narrow dispersion is great for near field in small rooms and large open spaces (live arena shows or conference facilities with multiple speakers covering specific zones). Moderately wide even dispersion (around 45 degrees left and right of centreline within 3db) is the best in a larger sized domestic settings. The key to good sound is to keep direct and reflected energy balanced across the frequency range. Imaging is most accurate with narrow dispersion and a near seated position - this is simple because reflections are reduced relative to direct sound. However this doesn’t sound natural. Consistent directivity is very important- there should be no bumps in directivity across the crossover. Genelec are wide even dispersion designs with well controlled directivity across the frequency range. ATC or Neumann are also excellent. B&W typically have a discontinuity in directivity at the crossover point between midrange and tweeter (gives the BBC dip or smilie EQ when placed in a room) Small Two way Horns tend to have discontinuity in their crossover region too. Large JBL, Westlakes etc. with large waveguide horns coupled with large woofers and low crossovers points can be even also. Many ways to achieve excellent sound. An analogy is a flashlight vs a floodlight vs a lightbulb. Lighting feels more natural when it is even - it is the same with sound.
i like how you think and your flashlight analogy - light and sound should look and sound- ahemmm -well NATURAL or REAListic lol
What do you mean by small rooms and large size domestic rooms here?
Is a Von Schweikert dynamic speaker with multiple drivers and obtains a consistent very wide dispersion with little loss (it has a sweet spot but such a very wide comparable sound) a wide dispersion speaker or a narrow dispersion speaker? I dislike speakers which have very strong narrow dispersion/head in a vise type (25 years ago Martin Logan Monolith III which my wife hated, giant Duntech dynamic speakers, so many others which have narrow sweet spots.
Dispersion is at the very top of the list of importance for professional speakers but often no more than an afterthought for consumer speakers. Ironically it is usually more important in the untreated rooms most of us listen in. Cone drivers have a characteristic dispersion that varies enormously across the frequency range, and that’s not a good thing. A given driver will tend toward omnidirectionality at bass frequencies while exhibiting increasing beaming, or focused lobes of concentrated directivity. These are all negatives for the listener.
Recent advances in design and fabrication of horns have allowed exceptionally even dispersion across a wide band of frequencies that no amount of cone drivers can match. The research required to make these is beyond the scope of almost all loudspeaker manufacturers, so we don’t see much of this in home speakers, regardless of price.
Very well said. Thank you. You might find my long string of comments with Matt entertaining.
Stewart Markley I tend to agree with you that the term waveguide is used excessively and very often to describe what is objectively a horn. The amazingly complex devices manufactured by JBL and Electro Voice that have brought a whole new level of dispersion control to compression drivers are, by anyone’s understanding, horns. I don’t care enough to evangelize on the topic but I don’t need a new name for the very best in horn design.
@@artysanmobile Absolutely agree.
Stewart Markley Not to harp on about it, but there are many examples of directivity enhancements which can and should be called waveguides as that logically describes what they do. Two different things, two different names.
Thanks for this video. Another brilliant episode wich Matt. What I am always wondering about: How will you know what kind of speakers you have? Asking as most manufactures do not provide any specs in that regard.
A few hints 48 minutes into this clip:
ua-cam.com/video/1bbmWd00HYM/v-deo.html
That can be a complicated question. It really is too bad that manufacturers don’t provide more information. Traditionally you would use the DI to know this.
My suggestion is to to do one of a few things: A) buy speakers you can see measurements on. Reviewers like us take fairly comprehensive measurements on speakers and that provides the info you need.
B) in general dome tweeters with no waveguide and all direct radiating midrange or woofers are wide directivity. Panel speakers, waveguide speakers, and driver arrays are often narrow.
C) Ask me! I can usually tell by looking at it.
@@PoesAcoustics So Dynaudio Excite series is what I have (X38 and X14). From your description these are wide dispersion most likely. Do you agree?
@@makemeinvisible1 Looks like the X38 and X14 are wide dispersion as they are traditional 2-way and 3-way speakers with normal tweeters. Their Confidence 60 and Evidence Platinum beam more due to their design. The video I posted explains it.
Frank Lautenbach yes i agree. The vast majority of tweeters beam at high frequencies. But looking at the average DI and it’s shape, I would expect such a speaker to behave as typical “wide” dispersion speakers. Those BMR’s I showed are an usual exception.
Bob Robins rational speaker placement is perfect for any speaker in any room.
So true, took a long time to get my Polk LSIM 707 there but once I did--amazing
@@mattgiunt yes, took me a while too but result is greater than any other tweak I've tried. Apply RSP to a correctly set up hifi and the real enjoyment of actually listeng to the music takes over.
@@tonycolbourne7694
Did you follow CQ guys post on UA-cam? He explains the whole concept beautifully
@@mattgiunt not seen that. I watched the live lecture with Bob and downloaded the pdf. Went from there. It's been about a year now and I havent touched my speakers since.
I got a full klipsch surround sound with an Onkyo txnr636 with a room that's 9 feet wide and 11feet tall, I just changed from pcm to bitstream and now all of the different listening options sound so insanely good. I've never been able to set my system up properly and my ypao or whatever mic got stolen I had my mains rf82ii's 40 hz, 150m bookshelf speakers were set to 60 and center was set to 60 too ( I'm a bass head....... after changing to bitstream I changed all speakers back to 80hz and then turned down my two subs
Idk what the distance should be set for me speakers if my measuring tape says my head's9 feet away do I put it at 9?
Should all my speakers are infront of me roughly 4 feet apart for the mains and the book shelf speakers are like a foot apart of the center. I dint have space , should center spread be off and loudness management be on?
WHAT SHOULD MY CENTEr image be set to
So this backs up the regular advice of always try and compare speakers in your own room before making a purchase. Just remember that once the choice is made never move anything in the room or change any materials and if you move house be prepared to purchase new speakers if the room makeup is very different haha.
FR drivers are great for low dispertion, with treble like a lazer! 😅
For video games at 7.1.4 I would think narrow dis. Speakers are best because then you get headphone or better than headphone pin point accuracy like the devs intended. Watch a movie and 90% of human voice is from center channel. Now play a video game and the person talking spin the camera, the person talking will move with the speakers. My klipsch my not be even close to accurate in a Frequency response but when it comes to pin point accuracy while watching Atmos movies or playing games I think they do absolutly fantastic
i like how you think and hear and it seems like it would be the best, but i also think in real life we dont try to focus on where a sound is coming from( in the real world )so in some ways it would seem to be most realistic to not be able to pin point where a Sound is exactly coming from- it should just sound natural without room reflections ,. also it seems that no center channel should be needed with correct front speaker placement
@@NomadicSociety agreed I just would like to see measurements of a recorded bird play that audio back on a set of surround and see how that turns out. (A difficult task indeed) I am also anti-center channel too I never saw the need for one for most cases, (in a movie theater I could see a benefit as it covers a large area and audience) but in home I no longer buy center channel speakers
What if there is a lack of symmetry in the room? For example no/distant wall on one side and nearby huge window/wall on the other side? In that case wouldn't narrower dispersion and even first reflection absorption on the nearby huge window/wall side to make it less different than the other ("open") side?
Also, while you say the absorbers don't have a "flat" response, is that relative to a concrete wall? Drywall? What about a window with drapes?
No, we do not want the rear output to get quieter. It should actually get louder to contribute depth and spaciousness to the imaging.
Great discussion, thanks
It’s not just coverage it’s pattern control over a specified frequency response.
BTW I caught Gene yawning at around 20:48, but anyways... There's a lot to think about on this subject. Specifically, on dispersion for surrounds, I'd think that, all other considerations like seating area coverage and so on, maybe it makes less difference between "narrow" and "wide" dispersion speaker when you have larger channel count. Because in MC, you are supplying the envelopment in the content, and so the room acoustics are less noticable in general. Also, for a MC system, you might be more likely to have a more damped room anyways, so dispersion differences less audible. For specific spatial cues, like EFX or whatever, I'd think a wide dispersion might be better, just so less chance of localizing to a specific speaker. Again though, the difference might not be so obvious for a high channel count system. I don't really have anything too astute to add, I agree that some more research should be done. Did you have a good look through AES journal papers? If I was at my office, I might be able to find something in my notes or binders.
Todd Welti thanks Todd. I tend to agree. I would favor a narrower dispersion largely only because they also tend to be much higher output. I could make an argument for less room interaction and maintaining more consistent pans but I think it’s all conjecture.
I have looked through the literature and couldn’t find anything good. It is my opinion that the level of the DI won’t rise to the level of frequency response issues. So while I feel strongly that DI differences are audibly different, I think that if you blinded people and asked them to choose, they might miss the difference the elevated DI makes in favor of other possible differences. As such I think the study must be done very carefully.
I would have two ways to address this: 1) a single speaker with variable dispersion where by the frequency response can be tightly controlled and the tilt of the power response precisely changed through changes in dispersion. 2) a huge sample of speakers with largely varying DI’s but otherwise excellent performance. In other words, a population sampling experiment. In the former you eliminate all other variables that might influence perception. In the latter you simply average it out. The latter is more pragmatic but also less sensitive. Both would use a MUSHRA test interface. That would then be used in Mono, Stereo, and Surround settings don’t the differences can be discerned with each. The surround study would be a very expensive study to complete I would think.
If you think of any papers I’ve missed on the topic, let me know. I couldn’t find anything that felt rigorous. It all seemed like generally casual observations.
Now Todd, if Lexicon would be willing to loan us a pair SL-1’s I am confident that I could complete such a study! I actually think that is the perfect way to do the study.
Todd Welti oh and....are you suggesting I was boring Gene?
Seems to me that one potential issue with surround speakers is that listeners off to the sides are often much closer to the near surround speakers than to the far ones. Todd (or Matt), have you any thoughts about using small J-arrays as surrounds, to reduce this loudness discrepancy?
D L yeah that is an approach suggested for commercial cinemas. Toole talks about it in his book when discussing CBT.
I think that for home use we could debate if such an array could be designed to have the coverage angles needed to make that work over such a small distance. It’s easier in a commercial setting. I would argue that regular waveguides would work fine. In fact most decent CD speakers that have relatively wide vertical dispersion or even symmetric dispersion in the horizontal and vertical range could work. With an M2 style, you could lay it o on it’s side. A coaxial could work especially well since they have symmetric directivity. The biggest problem with many coaxials is that they simply don’t have great measured performance. Kef and Genelec make some good ones, but you would ideally want narrower dispersion and higher output than those offer.
I have a means to measure this inside so I may give that a shot.
@@PoesAcoustics Thank you Matt, that all makes sense.
If you can listen to an original pair of Allison speakers in good working condition, you will hear truly wide, evenly distributed dispersion, combined with outstanding imaging.
You didn't mention magneplanar speakers such as the Magnepans (though you touched upon line source speakers). Do I understand correctly that Maggies have a narrow dispersion? (Thinking about it: they should have narrow dispersion in the vertical axis (that is, they reduce reflections from floor and ceiling), but what about the horizontal axis?
Cheers,
Stefan
I was torn between the golden ear Triton 5's or the SVS Ultras would you guys consider these great speakers at the 2k price point. I really loved the SVS and went with those but only bc no one ever reviews Golde ear and I don't know who Carrie's them. I was only able to physically hear the SVS Ultras? I would really appreciate your thoughts on golden ear Triton 5's. Sometimes I feel those may have been a bit better just not sure. Thanks Gene again without you I'd still be looking for the Moby Dick of towers lol. I went with SVS everything outside of the center which is Martin Logan motion8i😁!
Go with the Golden,👍💯✌️🔊
Hello. Can I use 6 ohms center speaker together with front and back 8 ohms speakers on denon 2600h avr? Thank you.
nikanim yes
I thought for sure that you would at least mention the Maggie style drivers with their mythical "head in a vise" directivity.
You are right I totally should have mentioned that. Yes planar and electrostatic panel speakers have such wide diaphragms that they inherently have very narrow directivity. Much narrower a than a throng I showed.
Excellent stuff guys, especially for us newbies. Thank you! Matt, I may have heard you wrong but, in commenting on the B&W polar plot, I thought I heard you say it’s impossible to cross a 1” dome tweeter w/ a 6-1/2” mid bass driver well. So many 2 ways are configured this way, and you mentioned in the last video that the M126be is one of your favorites. Did I hear you wrong or miss something? Thanks again.
I think it's a fine approach. A larger midrange 6 to 7 inches (maybe even 8) will definitely beam frequencies in the range of 2khz to 4khz. That's good in my opinion. They cause listening fatigue since they resonate in your ear canal. Reducing these frequencies off axis will reduce reflections.
Now you only have these harsh frequencies hitting you directly and don't get reinforcement from side wall reflections.
No complaints from me.
Worth mentioning I don't agree with Matt's assertion that Genelec are narrow directivity speakers. Genelec's coaxial The One's have ~65 degree dispersion which is in fact wider than Revel's Performa series (~60 degrees), which he categorizes as "wide dispersion"
Derelict Music a few thoughts. The Genelecs that with the coax that I am looking at have a power response DI of 8dB or so above 1khz. The Revel is 6dB. So I am not sure where you are getting your numbers but from what I see, the Genelec has narrower dispersion.
Second and more importantly, I State in the video that the narrow vs wide is a continuum and now a hard separation. I establish rough criteria and go with that, but certainly the revel and Genelec fall on either side of an arbitrary line in the spectrum.
I am surprised that the JBL M2 would fall into the narrow dispersion catagory. These are the flagship speakers for Sean Olive and HK. The very folks who have touted wide dispersion speaker designs.
Good video. Voice quality is a step down from prior, though. Maybe it's the headsets.
All these years I thought Klipsch were wide dispersion speakers. I was so wrong.
I see that you have Revel M126Be and M16 on your recommendation for wide dispersion. Doesnt they have waveguides? and shouldnt they be narrow dispersion? btw, thanks for this awesome video
They both have a DI under 6 so I’m calling them wide. A waveguide doesn’t automatically mean narrow. But as I said in the video, it’s a continuum, not a hard divide. They are in-between.
hmm, so with acoustic absorbers, is it fair to say that DIY is always best? So for example the vertical decay is know at differing degrees, if you measure at which point of the wall that degree would hit the wall, a section of the absorber acan be reinforced with denser or less dense absorption material. By doing so you can better acheive a flatter consistent level of absorption. Same with dispersion acoustic treatment id say. If its wide dispersion speakers and theres too much decay once it hits the wall, best to not place the diffuser any where there. Damn, this rabbit hole just gets more complexed. Someone let me know if I got this wrong. Im lookijng to get full range woofers as my first DIY speaker and the Voice induction is super low, indicating beaming. is beaming a stronger form of Low dispersion?
very informative, cheers.
Lateral reflections FTW!!! #teamwidedispersion
I'm really curious what speakers Matt would like more between the Revel f208's and the new JBL HD's that were mentioned. Those are the two that i'm currently looking at. I currently have the Klipsch RP-8000F's (Great speakers) but i'm looking to upgrade, hopefully for the last time, LOL. Thoughts?...
Normally I could give you an answer but James is the one who reviewed those and hasn’t been able to drop them off for me to hear.
@@PoesAcoustics - No worries. Well, I look forward to hearing what you guys think, at some point! 😉👍
Fellow audiophiles an OT. How loud do you listen to your music from you speakers in DB. I do 55-60 db is loud enough for my ears. How about yours. To measure it if you have not sound meter gear use your smartphones as the kit by downloading the app sound meter from the app store.
Background would be something less and depend on genre but actual listening is about 60 with peaks to 70 or so as measured by the smart phone.
It all depends on the size of your room, the sensitivity of your speakers and the capability of your amplifier.
My room is small & low ceiling with 90db sensitivity bookshelf speakers with a 30hz low frequency bass. A very high quality transparent 100w each channel stereo power amplifier.
I rarely turn the volume dial of my amplifier up over half way. Smaller rooms can sound amazing, are easier to work with and cost less on speakers, amplifiers etc.
What matters much more than wide vs narrow is constant directivity as per Floyd Toole's research at Harmann: response must be flat (lower level than on axis is allowed) under each angle off axis (360 deg) which implies a flat power response . You can attain that only with dipoles (Linkwitz LX531) which is narrow , omnipoles like the MLB's which are extremely wide , or cardioid like Kii Thee which are in between. Normal classic monopole boxes nearly never have anything close to constant directivity
Gerrit Govaerts you have some of your facts wrong. Floyd work never suggested a flat power response was desirable. Quite the opposite. The power response should be tilted. His work and that of Sean Olive has favored monopoles more than omnipoles.
Constant directivity can be achieved with many design approaches. The BMR’s have even dispersion out to 90 degrees of either side with almost no fall off. It’s the lowest DI of any monopole we have ever measured. It would follow what you describe.
My speakers use waveguides and large drivers. It has a fairly high DI. It literally Meets Keele’s definition of constant directivity as he defined in the EV patent.
In fact that is an important point. CD has a definition as it was a term coined in both a paper and patent. As such, the only definition we can use is that definition.
products.electrovoice.com/binary/EV_PABible-07-Add06-Constant_Directivity_White_Horn_Paper-1980.pdf
But you are not the first to misuse the term and even I find it a little confusing. The alternative term of controlled directivity usually requires that a speaker have a device that controls the directivity rather than allowing it to be as wide as possible. It also doesn’t necessarily imply constant directivity in the pejorative sense.
The vast majority of true constant directivity speakers are monopoles as most of them are pro audio. The term refers to having the same directivity over a wide range of frequencies. It does mean the same amplitude over a wide range of frequencies. In theory a perfect CD speaker would have a flat DI down to 20hz and up to 20khz. However it is not generally considered necessary to achieve such wide bandwidth constant directivity. I address all of this accurately in this and the last video.
Dipoles do not have a flat power response. Go lookup the definition of a dipole. It seems you saw that sound radiates out both sides of the speaker and assumed that meant 360 degree coverage. That isn’t what it means. A dipole design cancels sound to the sides causing mills which reduce sidewalk reflections. They still have strong rear and front coverage however. Such a design could meet the criteria of CD but few do. I would argue that Linkwitz designs don’t really.
The Kii is like a more extreme version of the waveguide speakers I mentioned. Via beam steering they cancel sound radiating to the back and sides to create a flat extended DI. They are the definition of a monopole as their love is completely forward facing. Unlike normal monopoles which radiate as omni in the bass, they radiate very little to the rear. Hence cardioid.
@@PoesAcoustics Look , we can argue about the definition of constant directivity all day long , but I am a simple guy and for me it means what it intuitively implies . No matter from wich direction you measure the response , it's the same response , allbeit lower or higher in volume and prefferably (not necessarilly) flat from every angle . That way , the tonality of the speaker is identical and neutral in every direction , implying I am hearing the same song from both direct and indirect sound , which should have some psycho-acoustical benefits I guess.
I cannot imagine any normal monopole (exluding cardioids) with a normal baffle size being truely Constant Directivity (in my understanding of CD) : wavelengths of more than a meter under 300 Hz and longer will easily warp around the baffle , creating an omnipole dispersion . Either you follow that up with a monopole dispersion in mids and highs or you loose CD . That seems logic to me . It also seems logic to me that if you have constant directivity throughout the whole audio frequency band AND a flat frequency response , you will automatically have a flat power response . Where is the flaw in my reasoning ? I think I have a good understanding of what a dipole is , including the physics and math involved (see link to pdf) . I agree however that Linkwitz designs (certainly the early ones ) are not true CD . That does not mean that true CD dipoles do not exist or cannot be built or designed . You just have to know how to do that . You will need a 3 or better 4 way system and dimension your drivers in coordination with your crossover point . For mids and highs this will need to be a naked no-baffle design in order for a high enough first dipole peak (drivers + baffle need to be as narrow as possible , hence no baffle) . Bass can use an H-frame for adequate dipole distance . By crossing drivers before they reach the first dipole peak (and using lotsa EQ) , you can ensure that each driver creates a perfect and constant figure of 8 dispersion , thus CD . The whole theory of dipoles and how to create CD dipoles with a no-baffle naked approach can be found here : www.dipolplus.de/thema11.php . Highly recommended .
And before you ask , yes I made a 3 way CD dipole for which I have measurements that prove CD in the horizontal plane from 20 Hz up to 10 Khz : 2 x 12 inch in H-frame with 480 mm dipole distance crossed at 340 Hz to 2x 5 inch mids crossed at 1700 Hz to a dipole AMT tweeter from Mundorf .
I normally do not consider cardioids to be monopoles as they can arise from a dipole in a U-frame, but I can see how you could.
On Floyd's research,IIRC the number one characteristic needed for high quality sound reproduction that everybody agreed upon by far was constant directivity (not necessarily flat power response , I agree) . My own experience backs that up . I toyed with classic monopoles for decades and never got a really satisfying sound image until I started building omni's and CD dipoles . There is no going back for me
Gerrit Govaerts as I’ve said to others, I can’t and won’t use different definitions because someone wants to use the term differently. You have much of the deformity correct, but you seem to assume this must be achieved over 360 degrees. You cited Toole as proof of this requirement. He has said no such thing and the highest scoring speakers in Harmans testing have largely been monopoles.
You are right, a monopole won’t maintain the same shaped response around 360 degrees, while mid and high frequencies do still radiate backwards, it’s typically at a much lower level. But that I can only say, what’s the problem? A speaker is meant to be placed out into a room but still largely near boundaries. Often within 3-6 feet. Some people place them even closer. Why would we need to have strong reflections off the front wall to achieve more consistent sound? If anything, I would want to avoid front wall reflections. It is lateral reflections which are the most important to achieving enhanced ASW. Even spaciousness is more important coming from the side and back wall than the front.
So why is it that you believe that even dispersion out the back of the speaker is so critical?
I think the term you need to coin here maybe is consistent directivity. As I said, constant and controlled directivity are terms that have been defined and widely used. Neither would include omni-directional speakers.
As for research on this topic: there is virtually no research investigating speakers which radiate evenly in 360 degrees. There is a bit of research that looked at monopoles vs dipoles but as I said, they don’t have an even response to the sisters. They have quite narrow directivity toward the front and back. Most of the work really was either poor in quality or inconclusive. The strongest findings in any of the studies concluded that untrained listeners seem to prefer wider dispersion, trained listeners seemed to prefer narrower dispersion, wider dispersion speakers tended to score slightly higher at Harman but this was never an explicit test, narrower directivity was preferred in multichannel systems (which makes sense since the surround speakers now give all those spatial cues and do so far more accurately).
@@PoesAcoustics Ok , I can agree on using consistent directivity , but the use of 'constant' is at least a bit misleading if it does not imply 360 deg. So why do I insist on consistent ? Well , basically bc I think it can't be a bad thing if all my indirect sound (including that from the front wall) sounds the same as my direct sound . If it does not sound the same , isn't that worse ? Does that not require my brain to make corrections for correct interpretation , taking away brain cpu power that is needed for creating the spatial image ? (Removing a subwoofer is such a example , where instead of missing the bass tones , you really loose imaging while your brain is reconstructing the missing base by using the harmonics) . In my experience , it does . I just cannot wrap my head around the fact that for my brain some indirect sound is less relevant than other indirect sound (and which would that be, and why ?) . Siegfried Linkwitz agrees with me : " The ear drum signals also contain cues about the room, though colored in the case of a loudspeaker that radiates a different spectrum in different directions. It has been my observation that a spatially more open and 3-dimensional auditory scene is created in one's mind when the loudspeakers radiate uniformly in all directions like dipoles or omnis do. The auditory scene has great clarity and distance but not the hard edges and closeness that a highly directional loudspeaker tends to produce" . TBH , he also added : "I do not know how consistent the radiation pattern has to be. Nor do I know that constant directivity over the whole frequency range is optimum"
But if Floyd did not mean 360 deg in using the term CD , then I stand corrected . Anyway you define it , CD is in my experience the most important characteristic of what makes a loudspeaker sound good , and way beyond any other measurement
Gerrit Govaerts I get where you are coming from. However I think what you want can be achieved just fine without having a speaker have 360 radiation. The ear/brains ability to discern the tonality and individuality of reflections is restricted to well above the modal zone of a room. Geddes has defined that as 500hz and in conversations with Floyd about this, be too basically says somewhere in that range. Say 300 to 500hz. What that means is that the sound radiating omnidirectionally below 500hz is not likely perceived as causing a colored reflection.
What you are saying is basically true but I see it mostly discussed in the context of first reflection points off the sidewalks, back wall, and to some extent floor and ceiling. Really the only area of disagreement is going to be first reflections off the front wall. The way my CD monopoles measure would lead to front wall reflections which simply combine with the bass range and add nothing in terms of mid/high spatial cues off that wall.
I think the bigger benefit of speakers as you describe is that they dramatically increase the ratio of reflected to direct sound and this provided a much larger and more spacious sounding image. At the expensive of image specificity. I think it is quite debatable which is preferable and find no surprise that the research on preference is inconclusive. Most experts who prefer wide dispersion rightly point out that precise imaging is not a real thing with real performances. The counter argument that Geddes and I use is that it IS a real thing with studio mastered music. The latter is a scenario where the musical performance is artificial. It never existed in real life as it does on that recording. That is a musical experience made up in the minds of the engineer and artists. As such, what they heard (which nearly always uses reflection free mixing and a very high direct to reflected ratio) is probably the closest we can come to reality. I happen to prefer that more direct sound but fully recognize that it is neither right nor wrong. It’s just a preference. As I said in the video, I’ve heard plenty of wide and even very wide dispersion speakers that I loved. Some that I would happily own.
And...if I were a rich man, I would happily have more than one system, one of which would use a very wide dispersion Speaker Capable of 360 degree dispersion and place them in a large and largely reflective room. Why? I’ve heard it before and for certain types of music I found it really enjoyable.
I too think CD is the most important factor in speaker design I just define it slightly differently than you.
Question: clipping kills tweeters because of the added HF component of the clipping, correct? Does bi-amping avoid that problem, since its likely the clipping will happen first on the woofer amp.
Don't use a underpowered or overpowered amplifier for your speakers. Problem solved 👌🏾
If your turning the volume dial of the amplifier all the way to the max and hear clipping then lower the volume 👍🏾
So for Home theater, would it ideally be best if the center channel was a wide dispersion speaker and all other channels narrow dispersion?
You can get both good wide dispersion and narrow dispersion speakers. But you need to carefully research wide dispersion speakers as lot's are poorly designed implemented.
My centre (it's called centre here in the UK) channel is a properly well implemented wide dispersion speaker. The advantages are explosions, crashes, action scenes etc from the centre channel have a 3D holographic like effect.
More natural realistic than a narrow dispersion speaker. Ie a explosion in real life beams sound in all directions, not just a narrow beam of sound.
Awesome video series, thank you guys!
Do you feel narrow or wide dispersion speakers would have an advantage in the following scenario?
1/ listening to music only
2/ untreated medium to large living room with hardwood floor (probably quite a few reflections)
3/ music may be listened to in several locations in the living room (sitting or standing)
4/ any attentive listening is done sitting on a couch turned 90 degrees relative to the plane of the speakers
5/ speakers near walls / corners
Wide dispersion could be perceived as having an advantage for points 1 to 3, while narrow dispersion speakers may be more suited for points 4 and 5...
1) what is your goal for soundstage? How far apart of the speakers and how far apart are you?
2)Get some sound diffusers and absorbers. These can had cheaply or made even cheaper and can be done in an artistic fashion for the Mrs. This will make the BIGGEST DIFFERENCE. Use a mirror from the seating position and find your reflection points.
3) Surround sound an option? IF not, this will lend to needing wide dispersion.
4) Tow your speakers a little, shouldn't be 90 degrees. Tow in until you get a phantom center
5) Depends on the speaker. Klipsch CornWall? Put in a corner or near a wall. Point is, every speaker will be different and especially when you consider room gain. Need to tinker with the placement to get it right.
Wide always. Unless in a small room maybe not a big deal, just my opinion.
A test I'd like to see in a blind test is to tell people that you've changed speakers but don't. Then choose the one you like.
Unlike Drax, this is all flying right over my head!
Good treatment guys on dispersion and it's perception. One comment though on your use of the term waveguides. In all of your references to waveguides, you are actually referring to horns. Horns and waveguides are similar but different. Horns actually accomplish two things. Besides guiding waves, horns act as a acoustic transformer because of their flare. Waveguides only direct waves. The only use of waveguides in speakers is a transmission line which has no flare. No one would use a waveguide in the front of a speaker unless they wanted an extremely narrow dispersion pattern. The use of the term waveguides to describe horns is incorrect and misleading.
We are not incorrect in how we used it. I use it consistently with the man who defined the difference. Earl Geddes.
The depth of the “horns” in question is far too shallow to provide the acoustic loading you speak of and are all considered waveguides per the definition be defined. Since he has reviewed much of this before I am confident he would agree.
@@PoesAcoustics Simple answer. Remove the driver from the waveguide and find out if there is a level difference. If there is, it's a horn. Waveguides do not match impedances.
Stewart Markley that’s incorrect and Geddes will not agree with you on this statement.
www.gedlee.com/Papers/What%20is%20a%20Waveguide.pdf
It’s his definition. If you disagree with him I suggest you take it up with him or publish your refutation of his definition.
Stewart Markley www.gedlee.com/downloads/AT/Chapter_6.pdf and this is more comprehensive If you still disagree.
@@PoesAcoustics I've read the papers you've referenced and while Mr. Geddes has done fine work, the differences in the terminologies is because of the primary objective differences between his efforts and that of Webster. Webster was focused on the objective of loading and impedance matching while this was ignored by Mr. Geddes because as he stated the aspect of efficiency was not important because solid state amplification provided plenty of power so his focus was on the aspect of directivity. Horn theory is a special case of waveguide theory which is more generalized. Einstein also had a special case of the theory of relativity but he called it the Special Theory of Relativity and then the generalized theory he called the General Theory of Relativity. He did not change the name even though the focus of the special theory was on relative motion while the focus of the general theory was on gravitational effects on light which also blossomed into energy and mass relationships and space/time relationships.
Mr. Geddes states in his What is a Waveguide paper "The equations that I used are completely different than the Horn Equation, so in a very real sense what I
had developed were not “horns” as Webster was thinking about them. On the other hand they are
indeed horns in the sense that a horn is any conduit of varying cross section (basically anything is a horn
under this definition). I do not agree that anything is a horn, for example acoustic transmission lines or microwave waveguides are not horns because they do not have a varying cross section, which he just stated that a horn has a varying cross section.
In the end, all waveguides of varying cross sections like we see on loudspeakers have both properties of impedance matching/loading and controlling the direction of sound. I do not see a need to change the original terminology just because of a later more generalized and different objectives of study. Horns are not bad, and waveguides are not bad, they just have different objectives which overlap in realization.
Harman's comparison listening room is very wide and treated so it might not have much of the side wall reflections.
My understanding is that the acoustics are adjustable.
Great video guys, many thanks. Just on the off-chance would you know the ProAc Tablette 10 Signature small bookshelf speakers and if they are wide or narrow dispersion? Basically, I have a very small listening room (with near-field listening) and have been forced to re-consider my speaker options due to worries about boomy bass and placement issues in a small non-treated room. The ProAc Tablettes are sealed speakers and can be placed near to the side/back walls with less problems. I assume narrow dispersion would be better in this set-up? Would be so grateful for some advice...thank you.
Marc Foss wide but likely a bit uneven off-axis and with some narrowing at the top end. I would still call them wide.
@@PoesAcoustics Thanks Matthew. I am trying to choose some standmounters for my small listening room. The electronics part seems fairly easy in comparison but finding the right bookshelf speakers is challenging for a small, non-optimal room. I am strongly considering room correction as a first option (and possibly some minor acoustic treatment). If I contacted you/Gene at a later date, would you be open to helping me with this on a consultancy basis? Hoping you will say yes!
Marc Foss yes. Contact me through Poesacoustics(at)gmail.com. Eventually this will be something we can offer right through the Audioholics website but for now you can contact me directly. I have various consulting packages depending on your needs.
@@PoesAcoustics Thank you. It may not be for a while as I still have to purchase my music system and move into the new apartment/listening room, but I definitely look forward to being in contact.
Truly excellent video, thank you both for your time and effort and expertise in making it. Congrats Matt on owning the GedLee Abbeys.
You taught me something I didn't realize: That absorption affects the frequency spectrum of specific individual reflections differently depending on their angle of incidence. Thank you!
Matt, in your opinion, what are the acoustic/psychoacoustic mechanisms which give rise to greater apparent source width (ASW) for wide-pattern speakers? I am under the impression that early same-side-wall reflections contribute, which implies that the Haas effect isn't 100% effective. But I may be mistaken, and/or unaware of other factors.
Thanks!
D L all lateral reflections, not same side. Both sides matter.
@@PoesAcoustics In your video "Optimizing Small Room Acoustics", at 31:10 to 31:55, you talk about early sidewall reflections being like a mirror image reflection of the speaker's output, and say that it "tends to smear the soundstage. " I agree with you. So here is my question: Is this "smearing of the soundstage" from this early sidewall reflection PART OF what creates Toole's "apparent source width", which wide dispersion speakers have more of? Or am I confused, and they are two different things?
Thanks!
D L hi DL, I wasn’t talking about that but it is the same thing. ASW our apparent source width is caused by lateral reflections and gives us the perception of width. Our auditory system is not fast enough to perceive those lateral reflections as discrete. As such the brain integrates them and it forms a widening or smearing of the image.
This is typically a desirable thing but in the example I was giving, I was suggesting that particular form of widening would be undesirable. Those very early lateral reflections also cause a lot of comb filtering which messes up the response and causes colorations. It also smears the image in a more unnatural way. When a speaker is placed right against a wall the reflections are so early that while they do cause a widening/smearing perceived as ASW, it’s not how we would hear such a thing if this was a real performance space. That is why you generally would prefer speakers farther from the side walls. At least a little gap is desirable to increase ASW sufficiently and in a more desirable way.
Of course another argument is we are all wet here and ASW is being misused in this context. It’s origins and majority of research has been in large symphonic halls, not homes. There are studies of small acoustic spaces to test hearing aid DSP and this gives us clues that the ASW effect remains present in small rooms and by 2 speakers. We also have anechoic chamber studies that show how it works even when the reflections are short. From that I like to think it all applies still just fine. But I know many of the measures like IACC tend to get messier in small rooms. I do binaural impulse measurements of rooms and calculate IACC sometimes and find the value fluctuates in strange ways in small rooms. Something I never had seen in large acoustic spaces before. There are also no standards to assess a small rooms quality based on its IACC due to a lack of research in this.
@@PoesAcoustics Thank you very much Matt for taking the time to reply in depth. I'm still a little confused as to the relationship between the Haas effect and apparent source width from lateral reflections, as they seem to both be in play at the same time.
Maybe I'm misusing the term "apparent source width", as I have been thinking of it in terms of "how wide the soundstage seems to be" but not in terms of "spaciousness" and "envelopment".
If I understand him correctly, Geddes finds that the early same-side-wall reflection is particularly detrimental, but can be essentially avoided with controlled directivity and aggressive toe-in. This results in the first significant lateral reflection of the left-hand speaker being the across-the-room bounce off the right-hand wall (and vice-versa), and because it arrives at the opposite ear from the first-arrival sound, the ear can process it as discrete. In his room his left and right main speakers are very close to the side walls, and toed in maybe 45 degrees.
At any rate Geddes advocates minimizing reflections arriving within 10 milliseconds of the direct sound, and my experience with a fairly wide range of dispersion patterns (including dipole, bipole, and other polydirectionals) agrees with that. Linkiwitz suggested 6 milliseconds, but ime there is worthwhile benefit from pushing it back to 10 milliseconds.
By the way I absolutely love something you said in that "Small Room Acoustics" video: “A speaker that has controlled dispersion does basically the same thing you'd expect an acoustic panel to do, but it does a better job. And it allows you to get away with no panels on the wall.”
Wish I'd been following these videos you've been making with Gene from the beginning. Just found you recently, so making up for lost time as I'm able to.
D L well so the HAAS effect is the psychoacoustical name for the precedence effect that I noted here. The first arriving sound dominates over the latter sound. The later reflection still impacts how we perceive the location of the sound source but is drowned out by the first arriving sound. So with that in mind, ASW is the widening of the sound image caused by those secondary lateral reflections. With binaural hearing, if the brain receives two equally spaced and timed direct sound waves and two equally spaced and delayed secondary waves it perceived that as one tone. It integrates them. But the secondary tones have the effect of widening the image. Haas actually goes into great detail of this including ASW.
I would argue that maybe saying Geddes is advocating for 10ms is putting words in his mouth. He states in his paper on ideal speaker directivity that
Thanks so much for this. Coming here from the SBIR discussion, and seeing you've adressed some of the issues I'm trying to wrap my head around. Your whole channel is a gold mine.
A thought on the narrow dispersion for studio recordings vs. wide dispersion for live recordings/classical. Might this also be a question about the character of the music itself?
I've heard rock bands live in very reverberant environments. Doesn't work. I've heard acoustic percussionists in reverberant environments, doesn't work.
I've heard choirs in churches, boy does that work. Brass bands playing christmas carols, the same.
The roles played by legato vs. staccato, bowed strings vs. pizzicato. From one extreme of church organs, voices and similar expressions with big chords and a flowing character, to the other of percussionists, drummers, palm muted strings with strong transients in rytmhically dense and complex works.
I would assume it influences how the music is recorded and mixed, and how we want it reproduced. It even gets me to thinking of how acoustic environments have influenced what kind of musical expressions are created under various circumstances (and recommend reading David Byrne/ How music works).
I don't see how any speakers can cover a "few seats" off axis of the sweet spot and still deliver the center imaging. The center image is created by balanced sound coming from right and left speaker. Maybe you are referring to HT, but music is more nuanced. If I tilt my head to the left, the image moves a bit to the left.
Using the trick he mentioned of towing them in extremely so that they cross in front of you.
I discussed it in this video and will go into it extensively in the next video. The concept is called time intensity trading.
We hear these phantom images or any image placement based on either the delay in the response to one ear vs the other or the difference in level. What is known as the Interaural Time Difference (ITD) and Interaural intensity Difference (IID). When the brain receives conflicting information it will use intensity over timing information and discard the timing difference.
What that means is that a center image is typically created due to a balance of ITD and IID when you are centered between the speakers. However, you can take advantage of the brains time intensity trading phenomena by using a speaker that has carefully controlled dispersion. Because that speaker will get quieter as you move off axis, you can aim them such that as you move to the side, the farther speaker gets louder and the nearer speaker gets quieter. The brain discards they timing difference and maintains a solid center image.
This phenomena as used with speakers has been written up a few times and the phenomena itself is a well known psychoacoustics property. In fact it takes on a different set of characteristics at low frequencies (where by we perceive longer LF tones as being louder). Here is a link to a primer on the topic and my presentation will go farther to explaining this. www.libinst.com/PublicArticles/Setup%20of%20WG%20Speakers.pdf
Matt explained it, so I'll just chime in and say that, given the right kind of speakers and setup, it works and works well.
dipole bass is directional !
Narrow dispersion is like an inverse black hole, wide dispersion is like an inverse red giant, so to speak.
I'm glad that Floyd Toole's work is being questioned. It doesn't tell the entire story.
Dr. Toole's work is excellent in many respects but I do not share the idea that early reflections are beneficial in most music in rooms. I recently heard a stunning example of the benefit of early reflections when Josh Groban was singing in his shower and it sounded much better than when singing in his living room. But when he started just talking in the shower, it was immediately evident how hard it was to understand what he was saying. This demonstrates that the brain considers early reflections with a solo singer (a simple sound source) to be more enjoyable when it is not trying to resolve fine details in the sound, but when it is trying to resolve fine details as in comprehending speech, it is difficult and not enjoyable. This means that for music which is complex (which means most music), we do not want to have early reflections which confuse the brain and make it difficult to resolve details.
That's my two cents.
How about b&w 685?narrow?
Well I would call it wide but the tweeter beams. It’s response isn’t consistent off-axis bower.
Have you ever measured dispersion of a panel speaker like a Martin Logan electrostatic? Do they really avoid ceiling and limit side wall reflections?
I haven’t measured them myself but that is my understanding and theoretically it makes sense. I have measured larger drivers and panel drivers such as large folded motion or planar drivers. I haven’t had the chance to measure an entire ML electrostat or similar. I’d like to some day.
Here is how I understand they measure: they have a dipole radiation pattern with a pinching of the dispersion to the sides where the sound wrapping around the front and back self-interferes and cancels the side radiation. The very wide panel leads to a very focused narrow pattern and the treble beams heavily. The dispersion pattern would look a bit more like a triangle.
ML curves the panel to address this dispersion problem and that helps to reduce the beaming, widen dispersion a bit, while still avoiding strong sidewall reflections.
Which is all to say that yes they shouldn’t have overly strong reflections to the side.
Now having said that, I had a client recently with on-wall ML electrostat speakers. One of them was placed near an object and appeared to be interacting with it. The reason for this was a design problem (and if I were ML I know how I would have fixed it). If you place a typical cardio for dipole radiator against a wall it becomes a monopole. It’s very likely that the midrange and low frequencies were still projecting strongly to the side which is exactly what we saw in a beat pattern in the measurements.
@@PoesAcoustics Thanks. I'm actually considering an all-electrostat ML surround setup, using the on-wall speakers for the surrounds. I won't have objects near the surrounds, but should I be concerned otherwise? Did that client's setup end up sounding good?
Sendu Bala he is still purchasing treatments. We did a test where by he grabbed a lot of pillows and blankets and used them as temporary treatments. I really had him do this to see what was causing what. However he did indicate the sound improving.
I personally believe that a dipole radiator like this against a wall isn’t a great idea. However if you want the best channel to channel consistency it is your only option. What I would probably do is consider mounting them onto an absorber and having an absorber around them if need be.
there should be a gap between the absorption panels a 6 inch gap where the tweeter would lie inline at the first reflection point and at the listening point there should be a 12-inch gap and you want the panels to go behind the speakers not just in front. You want your panels to be away from the wall to catch the deflection bounce back a good materials natural wool fleece just hang it an inch or so away from the wall
The Mbl could be directional if you put two side baffles splitting off between the dispersion from the back and front, the more you slope them more directional they would become. In the future can you mark on the pictures what speaker you talking about! because I can't tell by the picture what speaker you are representing, I'm assuming left to right top to bottom. Turn your mic gain down a little bit down it is over stretching it's parameters getting echoing from your room and sounds like the EQ is a little bit high in the mid to hide turn down a bit Gene
Which one of us was too high? Which one had too much midrange. Gene or me?
While what you say is essentially true for the MBL, why would you. The entire point of that speakers unique driver design is to provide an even flat power response. There are better monopoles if that is what you want.
I’m not really sure what you are saying about the panels. A 6” to 12” gap would be pretty large for most people. In fact 12” is on the verge of the panel not interacting with the wall behind it in a predictable way. It usually would lead to a lot of wobbles in the absorption response. A gap is good but 12” is extreme. If 12” is what you want I would suggest designing the absorber for that purpose.
In my room the curved panels are Vicoustic panels at about 2”-2.5” thick and sitting on a 1x3” frame. That frame is filled with a bonded cotton insulation. It has the equivalent absorption of a typical 6” thick panel.
Those blue free standing panels can’t be placed any closer than 2” from the wall due to the feet. The panel is about 4.5” thick and filled with a core of 8” mineral wool. It’s 4.5” thick on the bottom half and 2” on the top. The rest of the top has that same cotton bonded insulation which has better high frequency absorption.
People can’t see the rest of the treatments in the room
Because they are all hidden in some way. The walls articulate and are highly damped CLD. The front wall and front 30” of the side walls and ceiling have 4” of fiberglass bonded insulation with a film diaphragm layered at 2”. The corners have bass traps made from 6# insulation. The ceiling also has another 2.5” MLS diffuser/absorber that extends over 48” out from the screen and covers the first reflection point.
The rooms acoustics turned out so good that I use its measured result as my example to customers of what we target. Since few customers let me go this far with their rooms I have my own room and just two others I can use examples of near perfection.
@@PoesAcoustics I thought Gene was a bit sibilant lots of gain listing through a tablet
Wow... so much misinformation in this it's hard to know where to start. All the data I know of from AES papers yeild the same result - speakers with Wide smooth frequency response is prefered by listeners in blind trial again and again...
the misinformation is your misunderstanding of our presentation which went over your head.
Audio honks?😂
4 minutes and I stopped caring.... 🤦♂️
There are plenty of Justin Bieber videos on YT to hold your attention.
One reply and you've been owned. HAHA
suck it up buttercup!