1:41 This is done in aviation as well with the addition of what is called winglets. Adding wing-like structures to the wing tips does the same thing as the baffle by preventing the low pressure air from meeting the high pressure air in the best possible manner. Winglets are prevalent on most airliners flying these days because they reduce the drag induced with the lifting motion of the wing. Thank you for the explanation this. I am really amazed. Very well done! Cheers, be safe, and stay healthy! PS, sorry for the double comment!
Huh, neat, yeah I've seen a video of a jet without winglets going through an enormous smoke screen and seeing toroidal vortices the size of the plane itself, without winglets, is crazy, and yeah, I suppose it is an equivalence. One thing would be the time it takes the wing to travel its length would be the tuning frequency, so I'd expect thicker wings to require longer winglets.
0:20 It takes a lot to really catch my attention these days. Just when I thought I had a good grasp of how a speaker worked, here you come along. My mind is blown. I am kind of embarrassed actually. As soon as I saw the beginning of your video and with my background in aviation, I should have known that air movement would circulate around to the back. This air movement happens in aviation when the high pressure coming off the top of the wing providing lift and encountering the low pressure air. This is known as wake turbulence or "jet wash". Why I never thought about this can only be hypothesized as I never have used a speaker other than for signal testing purposes without a baffle or box. You have provided a great epiphany! Thank you!
1:41 This is done in aviation as well with the addition of what is called winglets. Adding wing-like structures to the wing tips does the same thing as the baffle by preventing the low pressure air from meeting the high pressure air in the best possible manner. Winglets are prevalent on most airliners flying these days because they reduce the drag induced with the lifting motion of the wing. Thank you for the explanation this. I am really amazed. Very well done! Cheers, be safe, and stay healthy!
This has solved my latest issue with my build. I want 4 15's in my tiny SUV. 2 pairs in iso-barik in an IB wall will achieve exactly what I've been looking for. Paired with 4 1" 120w RMS bullet tweeters, 2 8 inch midbass woofers, and 2 6.5 inch mid bass woofers, I should have the budget, entry level SQ setup I've been looking for.
Great explanation. I would argue that this presents more objective than subjective information. Good day. Have been subbed for about a year now. Keep it coming.
Yeah, I haven't seen a good explanation of the difference between an acoustic suspension and infinite baffle other than smaller than vas and larger than vas respectively, but driver Qts is an important factor, for determining enclosure Qtc, which is why I think it should be a factor in enclosure choice.
As I consider a pair of large ported enclosures in my living room or cutting holes in my floor for a crawlspace mounted IB setup, I would love to see similar comparison between those two enclosure types.
I maybe wrong, as far as I remember, the so called infinite baffle is simply an iteration of a sealed enclosure where the compliance of air inside the box is larger than that of the driver itself, a closed box then becomes an acoustic suspension design, when the enclosure is made small enough so that the compliance of the box is less than that of the driver by the factor of 3 or more. Qtc values below 0.5 are actually considered over rather than underdamped, the lower the Q the higher the damping, not the other way around. Higher Q means lower damping and larger resonance peak to put it simply, as per resonant circuits theory.
I've just had a good look at the equation for Qts, it seems the reason the Qts increases for smaller boxes is due to the compliance decreasing. If the mechanical resistance isn't altered much by the air, then it does seem the damping goes down with higher Qtc. I believed damping increased due to the restriction of the driver movement below resonance, but this is quite interesting. I originally theorised the air providing damping to the driver, as air (N2 and O2) isn't very springy compared with, say, carbon dioxide and sulfur hexaflouride, and this lack of springyness also contributed to damping. I should mention that I'm mostly self tought, and the Q's are the most recent area of audio I've looked into, but this has inspired a sort of epiphany.
@@Dakoustics A dynamic speaker near its fundamental resonance frequency can be approximated by a weight on a spring analogy. The greater the weight or the softer/more compliant the spring, the lower the resonance frequency. Conversely, the lesser the weight or the stiffer the spring, the higher the Fs. The formula is 1 over 2Pi times square root of Moving mass times Compliance with mass expressed in kilograms and compliance in metres per Newton of force. 10 grams of moving mass with 1mm/N of compliance equates to a fundamental resonance frequency of about 50Hz for example. Note that any combination will yield the same result as long as their product is the same. Air is unfortunately not a very good match for the cone, not a good medium to conduct/transmit the vibrations produced, as it presents very low resistance to its motion. Less than 1% of speaker input power turns into sound actually because of that, the balance turns into hot, not moving, air to put it simply. Air is too thin, too light, hence the invention of the horn enclosure, but that's a topic for another discussion. Mechanical Q or Qms tells you how long it takes for the cone to stop once pushed out of equilibrium. In short the longer it takes the higher the Q (heavyweight cone + soft spring) or low damping. The faster it comes to a halt, the lower the Q (lightweight cone + stiff spring) or high damping. All bass drivers fall somewhere in-between these two extremes. (Please note that listed moving mass values, Mmd and Mms, differ by inclusion of the cone loading for the latter, which is the weight of the air that "sticks" to the cone) Now make the weight out of iron and suspend it in strong magnetic field. If you try to move it abruptly now, that piece of iron will interact with the field and work along the suspension trying to keep the weight still, it will dampen the weight motion. And that's your Qes - the electrical damping, the stronger the magnet, the more turns of the coil wire inside the magnetic field, the lower the Qes, the higher the damping and finally the quicker the dying out of the post impulse cone oscillation. Here's where amplifiers play their part - low output resistance/high damping factor or lots of easily drawn current will considerably impact the cone motion. Considerable output impedance value adds to the speaker Revc value in short. That's also the reason why vacuum tube amplifiers with their impedance matching transformers are not be the best choice for low frequency reproduction in general, as the tubes are excellent voltage, but mediocre current amplifiers, but I'm digressing. Both Qs, both damping systems, then average out and give you the total Qts of the speaker, Qts = Qms x Qes over Qts + Qms). I admit, I have intentionally omitted the mechanical resistance of the suspension, Rms contribution to simplify the picture. It has a direct impact on the Qms value and can be approximated by turning the spring into a full blown car suspension shock absorber. It dissipates the coil vibrational energy, turning it into heat basically, and the higher the losses the lower the Qms, it does not directly impact the Qes value. Neoprene surrounds have high Rms values, pleated textile ones the opposite. Worth mentioning at this stage, that voice coil former material choice may increase total losses considerably due to interaction with magnetic field. So called cabinet losses itself also play its part, but again this a rather complicated subject and requires a lengthy discussion. Three simple equations describe the Qms, Qes and Vas parameters values, with the dynamic speaker equivalent circuit being the foundation for estimating the influence of the enclosure. Ambient air pressure and humidity for example, will also influence the parameters just as dynamic changes in response due to voice coil increase in temperature at higher loading levels. But the above is a gist of it I would think and the more you learn and explore, the less you know actually, as you dig deeper you only uncover layers upon layers of additional considerations. That's what makes it fun. If I may recommend a course of action it is to start at the beginning, familiarize yourself with the equations and books on speakers, beginning with those often published nearly a 100 years ago. This will give you the insight and idea on how our understanding evolved until this day. I've been playing with speakers for 25 years myself and If you asked me, whether I'm a knowledgeable I'd say no - I barely scratched the surface. Oh and btw, the simplest sealed enclosures, infinite baffle in particular, still sound the best to my by now aging ears. Gradual, albeit early roll-off is compensated by real life in room placement to such a degree, that with the right total cones displacement volume available and moderate levels it just sounds right all the way down. Anyways, love your channel and keep up the good work, only a fool thinks he knows it all !
@@paulb4661 Hi Paul... thanks for taking some of my confusion away. Great add on. I'd love to ask some more questions but don't know how to contact you other than via this comment box so if you wouldn't mind dropping me an email to shabixs@gmial.com to which I could reply it'd be much appreciated. Cheers mate. @Dakoustics great vid btw.
@@paulb4661 Good stuff ... Agreed, especially the middle of your comment, electrical damping, especially the amplifier aspect ... The short answer to the ubiquitous question about "fast bass" ... the key to woofer speed is instantaneous current availability. Fast bass in a general sense is a multitude of elements ... primarily a function of LF decay characteristics of the room.
@@FOH3663 Spot on Mate - loudspeakers' interaction with its surroundings is massively understated, placement first of all is of paramount importance and then at least a modest application of damping mats, at least where the first reflection takes place. Then of course concrete vs suspended timber floor, brick wall vs drywall and so on will massively influence low frequency characteristics. Dont you just love modern spaces full of hard surfaces with not a book shelf in sight ? 🤣 That zingy and fluttering echo - perfect .... not.
It seems like you got a bit confused what Qts and Qtc are. Qts and Qtc do show tendency of a driver to oscillate at it's resonance frequency. If Qts(Qtc) is about 0.5 the driver is not underdumped but rather overdumped. Also speakers with high Qts (Qtc) above 1 is not overdumped but underdumped and prone to resonate.
You are spot on, he got it all backwards: higher Q means less damping and not more. A Q of less than 0.7 in it's mounting is considered over-damped and suffers in loss of bass. But if you compensate the loss with a DSP, then you get a very controlled system.
I disagree with a couple points, but I certainly appreciate the content. 1.) Small/Sealed possesses no efficiency advantage over an IB alignment. 2.) I don't understand the variation in group delay IB vis-à-vis Small/Sealed Solid work Much appreciated
1. The efficiency is measured at resonance, so as the stiffness increases the resonance, it leads to it having a higher spl measurement at the new higher resonance, thus "higher efficiency". Maybe higher sensitivity would be more correct, but much of a muchness. 2. Variation in group delay is likely due to phase response wierdness around the resonance also. Cheers for the comment, hopefully this'll clear things up.
It is all about the driver. With a true IB the Q of the entire system will be the same as the Qts of the driver. If that is in your acceptable range and fs is appropriate go for it. The downside is that there is no acoustic loading to protect from over excursion so that has to be taken into consideration. One trick that can be used to help a driver with lowish Qts is a series non-polarized cap. With judicious choice of value it can create a response similar to an extended bass shelf and provide a 1st order HP filter for some protection. Depending on room gain the ideal fs and Qts may not be what you would otherwise expect.
I ran IB for a long time and they sounded great. I now run ported box since newer cars are a pain with IB because the spare tire is in the trunk floor.
Good explanation! An infinite baffle speaker is essentially an in wall speaker. A box is not the same as a baffle. The problem with box speakers and why open baffle sounds a lot better is because box speakers try to contain the bass energy inside the cabinet and fail. They end up resonating like the body of a musical instrument which is bad because that means. you can hear the speaker like you can any other musical instrument and that’s where the illusion of sound stage is destroyed. Also from a bass perspective, anything below 100 hertz radiates as a sphere. So it doesn’t matter which way a woofer driver is facing. And what happens in a box speaker is the woofer loads the pressure of the room creating a mushy boomy bass sound. On the other hand, with open baffle the 90 degree facing waves cancel out and the driver doesn’t load the room like a box speaker and as a result you get really tight, fast, and tone accurate bass. (No boom or mushiness). I recently got a pair of Spatial Audio X5 open baffle speakers and I can attest to this affect first hand. With my old pair of box tower speakers I had major room boom in the bass and it would hit a 50 hertz room mode that would shake my floor and walls. With my new Spatial Audio X5 open baffle speakers 98% of that is now gone. No more room boom and no more 50 hertz room mode! Just really fast, toneful and accurate bass that punches like Bruce Lee is hitting you in the chest.
Not true. Ib gives you faster sharp tones, the reason it does it because it doesn't need any load other than the mechanical load of the driver. You must be using a driver with the wrong parameters.
Group delay is basically an effect where certain frequencies take more or less time to get from the output of an amplifier to our ears, via the speakers. Example- You have speakers against the opposite wall, but the sub is next to the couch. The speakers will have a delay relative to the subwoofer. Example 2, a ported speaker- tuned to 40Hz, plays a 60Hz tone. Sound goes straight from the amp, to the speaker, to your ears, not much delay. But, if you play 40Hz, it goes amp, speaker, then the port absorbs a certain amount of sound before it starts to resonate properly, and this results in the sound taking longer to get to your ears.
Great explanation. I have a 12 with a qtc of .58 & vas about 40. I am building the enclosure to the maximum ported volume of 2.25 cf and ran it through a few calculators that said I should have 2.5 sealed or close to 5 ported to get a .707 qtc. I don’t want to give up more space than I was already planning to but it got me thinking maybe I should try it sealed for a while before I put the port in. I’m not looking for maximum power just something less peaky than the setup I’m currently running which was great in a small car but moving it to an suv certain frequencies don’t hit right. I hope it works out but am mainly doing it for the learning experience
This explains why I had a 1985 Cadillac Fleetwood and everything was electric including the trunk lid. I installed 2 subs in a sealed enclosure in the trunk. Bad thing was when I shut the trunk it killed ALL the low frequency. But unlock the trunk and the bass would explode.... So for a little while there I had to ride around with the lid open and take railroad tracks slowly to keep the lid from flying up in the air 😂😂.... {The things I'd go through just to hear that bass... I'm older now and don't really care anymore 😂}
So you know I went with sealed enclosures for my theater. I've got 5 sealed 18s and 6 sealed 15s, I get tons of response and if I drop the HPF I can get over 100dB at 8Hz! That's insane in a 1200 square foot home theater! That said, I was looking into going IB for my next "big build" which would have incorporated (16) 18" subs. Yes, 16 of them. I have a storage area behind my theater which is 3300 cubic feet (not sure what that is in litres) and that many 18" subs would have REALLY opened up my low frequency response. We're talking 150dB at 10Hz in a house! That'd be obnoxious and I wanted all of it! The thing that stopped me was the tuning (or lack their of) that I would have had to do. The biggest trade off is power handling. Even a 1000w RMS sub has to be ran at a FRACTION of its power to avoid hitting XMAX, or worse XMECH, when going in a space that big. So it's almost like you need 12 to 20 sub drivers in order to get the SPL you want! I may still go for it for the next big build, I know the driver I'd use (I'm in love with the Skar SDR series), I'd pick up 16 of them, and maybe spend a bit and buy a few of the Stereo Integrity 21s or 24 inch drivers to supplement them. I think 3300 cubic feet gives me a lot to work with. Sealed, for now, is the way I chose because I absolutely LOVE ULF. Hitting 10hz with authority is my JAM. I love that you put out videos like these, they always get the wheels in my head turning and make me want to go back down to my theater to build more. I need to do yet another tour of my theater as I've moved things around and re-packaged some of the existing items. I can't wait to see what comes from your channel next and I'm still thinking that you and I need to have a build challenge. Budget Audiophile vs Dakoustics. Let's go for battle of the ULF. Let's see who can hit the lowest notes the hardest, HAHAHA! Love this channel!
Holy crap, 16 18s! I can honestly say I don't know of a car audio build with more than that, except the 40 15" solobarik truck, but that's it. 3300 cubic feet is hard to fathom. Might be time for some structural reinforcement at that point. I've seen a bit on the stereo integrity 24" subs, craziness. I'll keep my eyes open for the next upload.
@@DakousticsI'm going to do a quick video today just showing the updates to the theater's configuration. I'm excited for the next part of my build. Almost as excited as I am to see where your build goes! The world needs more clean, ultra low bass!
Budget Audiophile your goal shouldn’t be to put as much power to the sub as possible. SPL is a product of xmax and cone area. Thats it. So you technically get more out of IB than sealed and you can play way lower
@@JayeBass I see what you're getting at but at the same time, 200w/sub is going to have a lot more headroom than 50w/sub. Digging deeper at a given level requires more wattage for a given driver. It's just electromotive forces in action.
IB is the way to go to get really low frequencies..but.. you can actually damage your house by going too crazy with it. Sound can be incredibly powerful. Do LOTS of research so you really understand it before you start your build. Good luck with your project!
I recently built my own subwoofers for my vehicle. Big into car audio. I built 6 15s with 300 Oz powerful magnets and a lot of excursion. The fs is low at 27hz which I like but the qts is very high at about 1.2. Have them in a 4th order and they sound great with a very large bandwidth from 20-60hz. What could I have done to be able to get the qts lower to be suitable for a 6th order enclosure? Did the suspension need to be stiffer or softer?
I want to do a stupid box where i make a fourth order blowthrough into my truck, but the sealed section is nonexistent/the bed of my truck/IB. I would likely use a sundown xv2 18 or 2 u15s. Any tips, concernes, advice, or reasons why I shouldn't? Il cone control could be an issue, but with a proper hpf, i dont think i need to be concerned with that. Im just not sure how damping would apply to/be an issue in this type of setup.
Maybe I can make a cone shape from the Boom Mat baffle product I purchased for the back speaker I bought, Kenwood, to free up the bass more, and then for the front I can put the baffles but only sealed.
Yes, it'd be infinite baffle. It'd have a low-ish Qtc, so balanced more towards peaks than tones, but main thing is be careful not to over-excursion it. At 17L, too, could be enough for it to be ported if you wanted.
Only real option is a ton of cone area, but to keep the lows not too much cone area or they'll be choked. Like a box more common in the 90s, with 8 12" subs in a 10 cube sealed box.
I am completely confused with qts/qtc values. How is possible for qtc to go down when the box gets smaller, as a smaller box provides more damping and as I have read,the q value is INVERSE PROPORTIONAL to damping ( low q means high damping)
Something I've wondered... How would a speaker perform if you somehow managed to hermetically seal the enclosure and had a vacuum within the enclosure. I'm sure somebody somewhere must have tried this.
I’m no scientist, but I would imagine it wouldn’t perform at all…if a vacuum was present inside the enclosure then it would be pulling the driver inward and would not be able to move to produce sound.
@@brandonhooker4498 Yes, of course the difference in pressure between the inside and outside of the enclosure would create a force pushing against the speaker driver. But this force could be overcome - either by increasing the power of the driver, or mounting an internal spring pushing the driver outwards.
So what sub do i need for small sealed enclosure since i need it in a corner of the car with custom small box,i thought about dd 506 or 608.. love deep high bass but need space for kids chairs and stuff etc..
*Oi mate old vid but i need some help so based off of this my Sundown x15 v1 with a Qts of 0.45 is good for an IB setup? Also cause its fs is 22hz 😅 any help would be appreciated*
I currently have two 10s in a 3.5ft3 enclosure. Available space is 38"w × 14.5"h × 22d. I want to upgrade my sub(s) for more BASS and am leaning toward a single 15" (Incriminator Audio Death Row). It's a SQ system that I do like to crank sometimes. What would you recommend for size/quantity? (1,500 watts RMS amp)
BTW if anyone wants the best Infinite baffle drivers they are made by AEspeakers aka acoustic elegance 15" with world's lowest fs(at least i haven't found anything diy lower than this apart from the 50" sub from ascendo) of just 16hz or the stereo integrity ib24 & ficar audio makes a spl car audio ib sub.
Sealed is not more efficient than IB. You didnt mention how much more power you’d have to send to the sealed box to be louder than the IB design. And WIN ISD is NOT the best way to educate yourself. Build the designs yourself and listen yourself. Sealed is great, so is ported, IB is superior. Less power need to hit same spl and the useable frequency response can often be produced to the single digits
Sealed being described as more efficient than infinite baffle is a reference to their use of the back pressure. IB ignores the back pressure, whereas sealed uses the back pressure to boost output at a higher frequency, so its more conceptual than practical. WinISD is what I muck around with every so often, I do build boxes, but simulations are much easier to muck around with than building a box and having every driver with every possible specification. It's also much easier to describe performance with a clean simulation than buying a couple subs and building boxes for them.
Dakoustics i understand that. It just doesnt always show what really is going on especially with IB. For example i’ve got 2 Tumult 15’s. WinISD would show their response startin to taper off around fs. But in reality they peak around 15hz with the amplifier they’re connected to and could be much lower with an amp that doesnt have a subsonic filter @10hz
@@JayeBass yeah, thats a good point, if you're interested in my "4th order v 6th order" video I mention how cabin gain massively improves the low-end performance of 4th order bandpasses, so although winISD would have you believe band passes are... welll... band passes, they in fact act more like low passes due to the +12dB/octave gain keeping up with the -12dB/octave roll off of the sealed portion of the 4th order. It'd be good if WinISD could process cabin gain, I've seen people comment it can with filters, but I haven't checked it out yet
dude, you keep bringing up new things, like Qtc or tones or whatever without properly defining them. what do the lettrers in Q stand for, as an example. and this whole video have very little direction it just keeps going off on random tangents. you are not alone in this but is a popular trend in speaker builder videos.
You have it backwards, a high Q is less damping, a low Q is high damped. You obviously do not understand what you are talking about, you mix terms, reverse terms and generally waffle on in your incorrect little world.
@@Dakoustics That totally depends on driver Q, a low Q driver will have no bass output in an infinate baffle where a high Q driver will sound very good. Acoustic suspension use small boxes to lift the Q at the expense of efficiency whereas a more conventional sealed cabinet will be larger and not use such a small box to bring the Q up to required spec with the extreme end being infinite baffle with a very high driver Q that does not require being raised by the cabinet. A low Q driver in a small box will not be peaky, just not efficient compared to a big box higher Q driver with the same F3. Basically the size of the box controls the efficiency/extension equation and you can load that box any way you like, with a ported or passive radiator system yielding lower distortion/ cone movement than any sealed driver.
The best audio explanations on youtube, no talking about subjective stuff. Majority of audiophiles talk about feelings without scientific background.
Because how good something sounds is largely based on your own ears
1:41 This is done in aviation as well with the addition of what is called winglets. Adding wing-like structures to the wing tips does the same thing as the baffle by preventing the low pressure air from meeting the high pressure air in the best possible manner. Winglets are prevalent on most airliners flying these days because they reduce the drag induced with the lifting motion of the wing. Thank you for the explanation this. I am really amazed. Very well done! Cheers, be safe, and stay healthy!
PS, sorry for the double comment!
Huh, neat, yeah I've seen a video of a jet without winglets going through an enormous smoke screen and seeing toroidal vortices the size of the plane itself, without winglets, is crazy, and yeah, I suppose it is an equivalence. One thing would be the time it takes the wing to travel its length would be the tuning frequency, so I'd expect thicker wings to require longer winglets.
0:20 It takes a lot to really catch my attention these days. Just when I thought I had a good grasp of how a speaker worked, here you come along. My mind is blown. I am kind of embarrassed actually. As soon as I saw the beginning of your video and with my background in aviation, I should have known that air movement would circulate around to the back. This air movement happens in aviation when the high pressure coming off the top of the wing providing lift and encountering the low pressure air. This is known as wake turbulence or "jet wash". Why I never thought about this can only be hypothesized as I never have used a speaker other than for signal testing purposes without a baffle or box. You have provided a great epiphany! Thank you!
1:41 This is done in aviation as well with the addition of what is called winglets. Adding wing-like structures to the wing tips does the same thing as the baffle by preventing the low pressure air from meeting the high pressure air in the best possible manner. Winglets are prevalent on most airliners flying these days because they reduce the drag induced with the lifting motion of the wing. Thank you for the explanation this. I am really amazed. Very well done! Cheers, be safe, and stay healthy!
The only thing I’d add is that you get 6db roll off per acoustic order:
6db per octave for IB
12db for sealed
24db for ported (4th order)
Etc
I agree gents, totally under rated and under appreciated.
Excellent explanation mate, since i'm watching your videos I'm starting to grasp the basics
This has solved my latest issue with my build. I want 4 15's in my tiny SUV. 2 pairs in iso-barik in an IB wall will achieve exactly what I've been looking for. Paired with 4 1" 120w RMS bullet tweeters, 2 8 inch midbass woofers, and 2 6.5 inch mid bass woofers, I should have the budget, entry level SQ setup I've been looking for.
4 15's for SQ is crazy
Entry level SQ setup without dedicated midranges? Not likely.
Wow, this is EXACTLY the type of information I was searching for! Kudos, thank you so much.
Great explanation. I would argue that this presents more objective than subjective information. Good day. Have been subbed for about a year now. Keep it coming.
Yeah, I haven't seen a good explanation of the difference between an acoustic suspension and infinite baffle other than smaller than vas and larger than vas respectively, but driver Qts is an important factor, for determining enclosure Qtc, which is why I think it should be a factor in enclosure choice.
@@Dakoustics Agreed.
As I consider a pair of large ported enclosures in my living room or cutting holes in my floor for a crawlspace mounted IB setup, I would love to see similar comparison between those two enclosure types.
I maybe wrong, as far as I remember, the so called infinite baffle is simply an iteration of a sealed enclosure where the compliance of air inside the box is larger than that of the driver itself, a closed box then becomes an acoustic suspension design, when the enclosure is made small enough so that the compliance of the box is less than that of the driver by the factor of 3 or more. Qtc values below 0.5 are actually considered over rather than underdamped, the lower the Q the higher the damping, not the other way around. Higher Q means lower damping and larger resonance peak to put it simply, as per resonant circuits theory.
I've just had a good look at the equation for Qts, it seems the reason the Qts increases for smaller boxes is due to the compliance decreasing. If the mechanical resistance isn't altered much by the air, then it does seem the damping goes down with higher Qtc. I believed damping increased due to the restriction of the driver movement below resonance, but this is quite interesting. I originally theorised the air providing damping to the driver, as air (N2 and O2) isn't very springy compared with, say, carbon dioxide and sulfur hexaflouride, and this lack of springyness also contributed to damping. I should mention that I'm mostly self tought, and the Q's are the most recent area of audio I've looked into, but this has inspired a sort of epiphany.
@@Dakoustics A dynamic speaker near its fundamental resonance frequency can be approximated by a weight on a spring analogy.
The greater the weight or the softer/more compliant the spring, the lower the resonance frequency.
Conversely, the lesser the weight or the stiffer the spring, the higher the Fs.
The formula is 1 over 2Pi times square root of Moving mass times Compliance with mass expressed in kilograms and compliance in metres per Newton of force.
10 grams of moving mass with 1mm/N of compliance equates to a fundamental resonance frequency of about 50Hz for example.
Note that any combination will yield the same result as long as their product is the same.
Air is unfortunately not a very good match for the cone, not a good medium to conduct/transmit the vibrations produced, as it presents very low resistance to its motion.
Less than 1% of speaker input power turns into sound actually because of that, the balance turns into hot, not moving, air to put it simply. Air is too thin, too light, hence the invention of the horn enclosure, but that's a topic for another discussion.
Mechanical Q or Qms tells you how long it takes for the cone to stop once pushed out of equilibrium.
In short the longer it takes the higher the Q (heavyweight cone + soft spring) or low damping.
The faster it comes to a halt, the lower the Q (lightweight cone + stiff spring) or high damping.
All bass drivers fall somewhere in-between these two extremes.
(Please note that listed moving mass values, Mmd and Mms, differ by inclusion of the cone loading for the latter, which is the weight of the air that "sticks" to the cone)
Now make the weight out of iron and suspend it in strong magnetic field.
If you try to move it abruptly now, that piece of iron will interact with the field and work along the suspension trying to keep the weight still, it will dampen the weight motion.
And that's your Qes - the electrical damping, the stronger the magnet, the more turns of the coil wire inside the magnetic field, the lower the Qes, the higher the damping and finally the quicker the dying out of the post impulse cone oscillation.
Here's where amplifiers play their part - low output resistance/high damping factor or lots of easily drawn current will considerably impact the cone motion.
Considerable output impedance value adds to the speaker Revc value in short.
That's also the reason why vacuum tube amplifiers with their impedance matching transformers are not be the best choice for low frequency reproduction in general, as the tubes are excellent voltage, but mediocre current amplifiers, but I'm digressing.
Both Qs, both damping systems, then average out and give you the total Qts of the speaker, Qts = Qms x Qes over Qts + Qms).
I admit, I have intentionally omitted the mechanical resistance of the suspension, Rms contribution to simplify the picture.
It has a direct impact on the Qms value and can be approximated by turning the spring into a full blown car suspension shock absorber.
It dissipates the coil vibrational energy, turning it into heat basically, and the higher the losses the lower the Qms, it does not directly impact the Qes value.
Neoprene surrounds have high Rms values, pleated textile ones the opposite.
Worth mentioning at this stage, that voice coil former material choice may increase total losses considerably due to interaction with magnetic field.
So called cabinet losses itself also play its part, but again this a rather complicated subject and requires a lengthy discussion.
Three simple equations describe the Qms, Qes and Vas parameters values, with the dynamic speaker equivalent circuit being the foundation for estimating the influence of the enclosure.
Ambient air pressure and humidity for example, will also influence the parameters just as dynamic changes in response due to voice coil increase in temperature at higher loading levels.
But the above is a gist of it I would think and the more you learn and explore, the less you know actually, as you dig deeper you only uncover layers upon layers of additional considerations.
That's what makes it fun.
If I may recommend a course of action it is to start at the beginning, familiarize yourself with the equations and books on speakers, beginning with those often published nearly a 100 years ago.
This will give you the insight and idea on how our understanding evolved until this day.
I've been playing with speakers for 25 years myself and If you asked me, whether I'm a knowledgeable I'd say no - I barely scratched the surface.
Oh and btw, the simplest sealed enclosures, infinite baffle in particular, still sound the best to my by now aging ears.
Gradual, albeit early roll-off is compensated by real life in room placement to such a degree, that with the right total cones displacement volume available and moderate levels it just sounds right all the way down.
Anyways, love your channel and keep up the good work, only a fool thinks he knows it all !
@@paulb4661 Hi Paul... thanks for taking some of my confusion away. Great add on. I'd love to ask some more questions but don't know how to contact you other than via this comment box so if you wouldn't mind dropping me an email to shabixs@gmial.com to which I could reply it'd be much appreciated. Cheers mate. @Dakoustics great vid btw.
@@paulb4661
Good stuff ...
Agreed, especially the middle of your comment, electrical damping, especially the amplifier aspect ...
The short answer to the ubiquitous question about "fast bass" ... the key to woofer speed is instantaneous current availability.
Fast bass in a general sense is a multitude of elements ... primarily a function of LF decay characteristics of the room.
@@FOH3663 Spot on Mate - loudspeakers' interaction with its surroundings is massively understated, placement first of all is of paramount importance and then at least a modest application of damping mats, at least where the first reflection takes place. Then of course concrete vs suspended timber floor, brick wall vs drywall and so on will massively influence low frequency characteristics. Dont you just love modern spaces full of hard surfaces with not a book shelf in sight ? 🤣 That zingy and fluttering echo - perfect .... not.
Lost before the Qtc/qts.. i try hard but even in french i don't understand everything😔
It seems like you got a bit confused what Qts and Qtc are. Qts and Qtc do show tendency of a driver to oscillate at it's resonance frequency. If Qts(Qtc) is about 0.5 the driver is not underdumped but rather overdumped. Also speakers with high Qts (Qtc) above 1 is not overdumped but underdumped and prone to resonate.
Yeah, got that backwards, was taught backwards.
I'm so confused now
You are spot on, he got it all backwards: higher Q means less damping and not more. A Q of less than 0.7 in it's mounting is considered over-damped and suffers in loss of bass. But if you compensate the loss with a DSP, then you get a very controlled system.
I disagree with a couple points, but I certainly appreciate the content.
1.) Small/Sealed possesses no efficiency advantage over an IB alignment.
2.) I don't understand the variation in group delay IB vis-à-vis Small/Sealed
Solid work
Much appreciated
1. The efficiency is measured at resonance, so as the stiffness increases the resonance, it leads to it having a higher spl measurement at the new higher resonance, thus "higher efficiency". Maybe higher sensitivity would be more correct, but much of a muchness.
2. Variation in group delay is likely due to phase response wierdness around the resonance also.
Cheers for the comment, hopefully this'll clear things up.
Thanks for the video! Perhaps you can make a video about cone vs dome drivers. Thanks
It is all about the driver. With a true IB the Q of the entire system will be the same as the Qts of the driver. If that is in your acceptable range and fs is appropriate go for it. The downside is that there is no acoustic loading to protect from over excursion so that has to be taken into consideration.
One trick that can be used to help a driver with lowish Qts is a series non-polarized cap. With judicious choice of value it can create a response similar to an extended bass shelf and provide a 1st order HP filter for some protection.
Depending on room gain the ideal fs and Qts may not be what you would otherwise expect.
I ran IB for a long time and they sounded great. I now run ported box since newer cars are a pain with IB because the spare tire is in the trunk floor.
Good explanation! An infinite baffle speaker is essentially an in wall speaker. A box is not the same as a baffle. The problem with box speakers and why open baffle sounds a lot better is because box speakers try to contain the bass energy inside the cabinet and fail. They end up resonating like the body of a musical instrument which is bad because that means. you can hear the speaker like you can any other musical instrument and that’s where the illusion of sound stage is destroyed. Also from a bass perspective, anything below 100 hertz radiates as a sphere. So it doesn’t matter which way a woofer driver is facing. And what happens in a box speaker is the woofer loads the pressure of the room creating a mushy boomy bass sound. On the other hand, with open baffle the 90 degree facing waves cancel out and the driver doesn’t load the room like a box speaker and as a result you get really tight, fast, and tone accurate bass. (No boom or mushiness). I recently got a pair of Spatial Audio X5 open baffle speakers and I can attest to this affect first hand. With my old pair of box tower speakers I had major room boom in the bass and it would hit a 50 hertz room mode that would shake my floor and walls. With my new Spatial Audio X5 open baffle speakers 98% of that is now gone. No more room boom and no more 50 hertz room mode! Just really fast, toneful and accurate bass that punches like Bruce Lee is hitting you in the chest.
Not true. Ib gives you faster sharp tones, the reason it does it because it doesn't need any load other than the mechanical load of the driver. You must be using a driver with the wrong parameters.
@@dooflydetailguuy4349 i dont think he was referring to IB in either case here. OB vs box (AS, ported)
Hey, love all your content. Can you or any briefly explain group delay?
Thank you
Group delay is basically an effect where certain frequencies take more or less time to get from the output of an amplifier to our ears, via the speakers.
Example- You have speakers against the opposite wall, but the sub is next to the couch. The speakers will have a delay relative to the subwoofer.
Example 2, a ported speaker- tuned to 40Hz, plays a 60Hz tone. Sound goes straight from the amp, to the speaker, to your ears, not much delay.
But, if you play 40Hz, it goes amp, speaker, then the port absorbs a certain amount of sound before it starts to resonate properly, and this results in the sound taking longer to get to your ears.
good on ya mate. i'm trying to do a crash course in speaker drivers and this is bang on what i needed.
Great explanation. I have a 12 with a qtc of .58 & vas about 40. I am building the enclosure to the maximum ported volume of 2.25 cf and ran it through a few calculators that said I should have 2.5 sealed or close to 5 ported to get a .707 qtc. I don’t want to give up more space than I was already planning to but it got me thinking maybe I should try it sealed for a while before I put the port in. I’m not looking for maximum power just something less peaky than the setup I’m currently running which was great in a small car but moving it to an suv certain frequencies don’t hit right. I hope it works out but am mainly doing it for the learning experience
How did it go?
I tried it sealed and then added a port. It worked pretty well sealed and had a nice wide range but I prefer the sound of a ported enclosure.
@@gregblau8082 Roger that; to what did you tune?
31
This explains why
I had a 1985 Cadillac Fleetwood and everything was electric including the trunk lid. I installed 2 subs in a sealed enclosure in the trunk. Bad thing was when I shut the trunk it killed ALL the low frequency. But unlock the trunk and the bass would explode.... So for a little while there I had to ride around with the lid open and take railroad tracks slowly to keep the lid from flying up in the air 😂😂.... {The things I'd go through just to hear that bass... I'm older now and don't really care anymore 😂}
If I make a sealed box for two twelves total RMS 2400 watts can I make a box a Lil bit bigger from spec??
This video is a breath of fresh air after watching all these others dudes who are basically paid advertising for audio companies
What if the driver is mounted in a vehicle with one side of the driver outside the vehicle?
So you know I went with sealed enclosures for my theater. I've got 5 sealed 18s and 6 sealed 15s, I get tons of response and if I drop the HPF I can get over 100dB at 8Hz! That's insane in a 1200 square foot home theater! That said, I was looking into going IB for my next "big build" which would have incorporated (16) 18" subs. Yes, 16 of them. I have a storage area behind my theater which is 3300 cubic feet (not sure what that is in litres) and that many 18" subs would have REALLY opened up my low frequency response. We're talking 150dB at 10Hz in a house! That'd be obnoxious and I wanted all of it! The thing that stopped me was the tuning (or lack their of) that I would have had to do. The biggest trade off is power handling. Even a 1000w RMS sub has to be ran at a FRACTION of its power to avoid hitting XMAX, or worse XMECH, when going in a space that big. So it's almost like you need 12 to 20 sub drivers in order to get the SPL you want!
I may still go for it for the next big build, I know the driver I'd use (I'm in love with the Skar SDR series), I'd pick up 16 of them, and maybe spend a bit and buy a few of the Stereo Integrity 21s or 24 inch drivers to supplement them. I think 3300 cubic feet gives me a lot to work with. Sealed, for now, is the way I chose because I absolutely LOVE ULF. Hitting 10hz with authority is my JAM.
I love that you put out videos like these, they always get the wheels in my head turning and make me want to go back down to my theater to build more. I need to do yet another tour of my theater as I've moved things around and re-packaged some of the existing items. I can't wait to see what comes from your channel next and I'm still thinking that you and I need to have a build challenge. Budget Audiophile vs Dakoustics. Let's go for battle of the ULF. Let's see who can hit the lowest notes the hardest, HAHAHA!
Love this channel!
Holy crap, 16 18s! I can honestly say I don't know of a car audio build with more than that, except the 40 15" solobarik truck, but that's it. 3300 cubic feet is hard to fathom. Might be time for some structural reinforcement at that point. I've seen a bit on the stereo integrity 24" subs, craziness. I'll keep my eyes open for the next upload.
@@DakousticsI'm going to do a quick video today just showing the updates to the theater's configuration. I'm excited for the next part of my build. Almost as excited as I am to see where your build goes!
The world needs more clean, ultra low bass!
Budget Audiophile your goal shouldn’t be to put as much power to the sub as possible. SPL is a product of xmax and cone area. Thats it. So you technically get more out of IB than sealed and you can play way lower
@@JayeBass I see what you're getting at but at the same time, 200w/sub is going to have a lot more headroom than 50w/sub.
Digging deeper at a given level requires more wattage for a given driver. It's just electromotive forces in action.
IB is the way to go to get really low frequencies..but.. you can actually damage your house by going too crazy with it. Sound can be incredibly powerful. Do LOTS of research so you really understand it before you start your build. Good luck with your project!
I recently built my own subwoofers for my vehicle. Big into car audio. I built 6 15s with 300 Oz powerful magnets and a lot of excursion. The fs is low at 27hz which I like but the qts is very high at about 1.2. Have them in a 4th order and they sound great with a very large bandwidth from 20-60hz. What could I have done to be able to get the qts lower to be suitable for a 6th order enclosure? Did the suspension need to be stiffer or softer?
So a higher Qts and higher Vas is better for infinite baffle.
Awesome video. Thank you for all the knowledge and science. I love subwoofers.
I want to do a stupid box where i make a fourth order blowthrough into my truck, but the sealed section is nonexistent/the bed of my truck/IB. I would likely use a sundown xv2 18 or 2 u15s. Any tips, concernes, advice, or reasons why I shouldn't? Il cone control could be an issue, but with a proper hpf, i dont think i need to be concerned with that. Im just not sure how damping would apply to/be an issue in this type of setup.
Maybe I can make a cone shape from the Boom Mat baffle product I purchased for the back speaker I bought, Kenwood, to free up the bass more, and then for the front I can put the baffles but only sealed.
how about a 8 inch sub driver with Qtc 0,5 and 9mm x-max and 10,5 lieter Vas in a 17 liter box ...would be infinite baffle is that ideal?
Yes, it'd be infinite baffle. It'd have a low-ish Qtc, so balanced more towards peaks than tones, but main thing is be careful not to over-excursion it. At 17L, too, could be enough for it to be ported if you wanted.
So how do I SLAM the lows AND get loud AF without porting or bandpassing?
Only real option is a ton of cone area, but to keep the lows not too much cone area or they'll be choked. Like a box more common in the 90s, with 8 12" subs in a 10 cube sealed box.
@@Dakoustics I just saw a video where two infinite baffle 18's on 400W total did a hair trick at 18hz.
I am completely confused with qts/qtc values. How is possible for qtc to go down when the box gets smaller,
as a smaller box provides more damping and as I have read,the q value is INVERSE PROPORTIONAL to damping ( low q means high damping)
Will a ib setup distort or mess with rear deck speakers? (6x9) and also can you mix ported 6x9s with a ib setup? Or it’s different responses?
Isn’t sealed and infinite baffle the same thing,ie,no hole in the box?
Something I've wondered...
How would a speaker perform if you somehow managed to hermetically seal the enclosure and had a vacuum within the enclosure.
I'm sure somebody somewhere must have tried this.
I’m no scientist, but I would imagine it wouldn’t perform at all…if a vacuum was present inside the enclosure then it would be pulling the driver inward and would not be able to move to produce sound.
@@brandonhooker4498 Yes, of course the difference in pressure between the inside and outside of the enclosure would create a force pushing against the speaker driver.
But this force could be overcome - either by increasing the power of the driver, or mounting an internal spring pushing the driver outwards.
So what sub do i need for small sealed enclosure since i need it in a corner of the car with custom small box,i thought about dd 506 or 608.. love deep high bass but need space for kids chairs and stuff etc..
Isobaric (1/2 vas)
*Oi mate old vid but i need some help so based off of this my Sundown x15 v1 with a Qts of 0.45 is good for an IB setup? Also cause its fs is 22hz 😅 any help would be appreciated*
I currently have two 10s in a 3.5ft3 enclosure. Available space is 38"w × 14.5"h × 22d. I want to upgrade my sub(s) for more BASS and am leaning toward a single 15" (Incriminator Audio Death Row). It's a SQ system that I do like to crank sometimes. What would you recommend for size/quantity? (1,500 watts RMS amp)
Are there any good books on sub speakers and boxes you could recommend? Thanx for all the great content 👍👍
Loudspeaker Design Cookbook is good from what I've heard, I should pick up a copy.
Crutchfield..
BTW if anyone wants the best Infinite baffle drivers they are made by AEspeakers aka acoustic elegance 15" with world's lowest fs(at least i haven't found anything diy lower than this apart from the 50" sub from ascendo) of just 16hz or the stereo integrity ib24 & ficar audio makes a spl car audio ib sub.
How can I download winisd for free?
WinISD Pro Alpha should be free off the website
Sealed is not more efficient than IB. You didnt mention how much more power you’d have to send to the sealed box to be louder than the IB design. And WIN ISD is NOT the best way to educate yourself. Build the designs yourself and listen yourself. Sealed is great, so is ported, IB is superior. Less power need to hit same spl and the useable frequency response can often be produced to the single digits
Sealed being described as more efficient than infinite baffle is a reference to their use of the back pressure. IB ignores the back pressure, whereas sealed uses the back pressure to boost output at a higher frequency, so its more conceptual than practical.
WinISD is what I muck around with every so often, I do build boxes, but simulations are much easier to muck around with than building a box and having every driver with every possible specification. It's also much easier to describe performance with a clean simulation than buying a couple subs and building boxes for them.
Dakoustics i understand that. It just doesnt always show what really is going on especially with IB. For example i’ve got 2 Tumult 15’s. WinISD would show their response startin to taper off around fs. But in reality they peak around 15hz with the amplifier they’re connected to and could be much lower with an amp that doesnt have a subsonic filter @10hz
@@JayeBass yeah, thats a good point, if you're interested in my "4th order v 6th order" video I mention how cabin gain massively improves the low-end performance of 4th order bandpasses, so although winISD would have you believe band passes are... welll... band passes, they in fact act more like low passes due to the +12dB/octave gain keeping up with the -12dB/octave roll off of the sealed portion of the 4th order. It'd be good if WinISD could process cabin gain, I've seen people comment it can with filters, but I haven't checked it out yet
Ib is the best, never heard anything in a box sound good
dude, you keep bringing up new things, like Qtc or tones or whatever without properly defining them. what do the lettrers in Q stand for, as an example. and this whole video have very little direction it just keeps going off on random tangents.
you are not alone in this but is a popular trend in speaker builder videos.
thank you :D
no problem heh
Thx !
It took me 3 minutes to realize that you weren't talking about the driver of the car...
yeah, talking about windows audio drivers, I know it gets confusing, one guy got my submarine video confused with subway, the sandwich lmao
😆
Neither. Open buffle is an only architecture that does not add an artificial sound.
They don’t look the same a sealed box will get HOT
too much damping is "overdamped", not "underdamped". A Q of 0.5 is overdamped.
Yeah a infinite baffle is quite hard to reach in a car.
You have it backwards, a high Q is less damping, a low Q is high damped.
You obviously do not understand what you are talking about, you mix terms, reverse terms and generally waffle on in your incorrect little world.
Yeah, got Q's backwards lmao, but yeah main point still comes across, small sealed tunes high/is peaky, big IB tunes low and smooth.
@@Dakoustics That totally depends on driver Q, a low Q driver will have no bass output in an infinate baffle where a high Q driver will sound very good.
Acoustic suspension use small boxes to lift the Q at the expense of efficiency whereas a more conventional sealed cabinet will be larger and not use such a small box to bring the Q up to required spec with the extreme end being infinite baffle with a very high driver Q that does not require being raised by the cabinet.
A low Q driver in a small box will not be peaky, just not efficient compared to a big box higher Q driver with the same F3.
Basically the size of the box controls the efficiency/extension equation and you can load that box any way you like, with a ported or passive radiator system yielding lower distortion/ cone movement than any sealed driver.