IMF TLS80's were the absolute best sounding speakers I have ever owned. Tympani drums and cathedral organs were right there in your living room.....best natural uncompressed bass ever!
PMC does TL absolutely right. Their midrange and mid bass are superb and clean because the line is designed properly and dampened correctly. Few speakers can match the clarity and extension. Most manufacturers just can’t stomach the time, effort and cost to build the cabinets. Still love my GB1i’s!!
I actually knew Bud Fried. A client of mine in public accounting has a son that bought his company. Bud was often there consulting on design. He was an interesting guy to say the least. A real legend in the business
Still rocking the pair of TL speakers I designed and built about 40 years ago. I had to re-foam the woofers about 10 years ago. I recall spending at least as much time tuning, using some equipment I borrowed from work, them as I did building them. I was just out of college and told my parents I wanted 4 sheets of 3/4 in. particle board for Christmas. When I made it home for the holiday, fired up my dad's table saw and cut all the pieces and packed that into my car and drove ~1000 miles back home. Then assembled the parts in my apartment. A few years later, I made a spur of the moment drive from the SF Bay Area to Seattle to grab 4 - 10" TL drivers from Speaker Lab, I think that was the last 4 they had in stock. These replace the original 8" drivers I originally used. All the crossover coils were hand wound out of 14AWG enameled wire. They are large, 2 feet square and 4 feet tall, sized for the 4x8 foot sheet of particle board.
Thanks Chris. Transmission lines got me into speaker building. There was one at the hi-fi shop in Pullman where I went to school. It would shake the tiles in the suspended ceiling which was totally amazing to me. I've built a few over the years but am more of a ported box guy these days, mainly due to the more reasonable enclosure size.
Always learn something useful when Chris and Paul share their lunch conversation. I have been hearing folks rave about some diyaudio TL speakers. Good to know something about them.
I remember meeting Irving Fred at in New Jersey Audio salon over 45 years ago when I was looking for a new pair of speakers. I was never a giant fan of IMF. I wound up buying Dahlquist DQ-10's. Never regretted that purchase for one minute. I would've never been happy with Fried boxes Not after hearing the Dahlquists. You guys keep up the great job you're doing with detailing us on speaker design.
John Wright designed the transmission-line designs of IMF. Bud brokered the marketing deal by setting IMF (and John Wright) up in the UK and importing/distributing them. TL designs can fail terribly in the wrong room acoustic. The Dahlquist was and is still regarded highly by engineers over here too.
I first heard Rega ELA transmission lines in the early 90's using the Naim Nait and was amazed at how natural and smooth bass notes were over a variety of frequencies. Not 'clumpy' bass kicks and booming in one area, they just 'breathe' music in a way I've never found before. Now I'm using an IPL kit and very happy. All things have pros and cons and it's down to individual tastes but I love TLs!
I really enjoy Chris's insights on speaker design. I still have my DCM TF600 speakers, an interesting design with transmission line bass, coaxial design with the tweeter mounted over the mid bass driver and two rear firing tweeters working at a lower volume. They have a very natural sound with a holographic midrange. How the heck DCM got this design to work is a mystery. lol
The RTL range are actually reflex/transmission line but still good. If you ever get the chance to hear their earlier Studio 3, Studio 4, Monitor, or Reference Standard, then do! They are true transmission lines.
I have worked my way up from RTL 2's, RTL 3's, to Studio 1's, the better version with the rebated cones. They don't kick butt like the Tannoy DC3000's in the living room, but with the volume low, as I have to have it in the evenings, when my wife is in bed, they loose none of the bass. Like the Tannoy's, they'll probably see me out :).
I have the Meadowlark Kestrel. They are astounding sounding and really getting them placed properly is a big part. The base reproduction belies their size. Time coherent on top of that. Just amazing.
Cool subject and nice to hear that Chris is also following the single driver developments that are mainly self build speakers. Now that we are talking about transmission lines, just for the heck of it it would be great to get a talk about Karlsson resonators. Can they be considered wide band transmission lines? can the colouring be mitigated? I have always been fascinated by them.
I worked with Pete Thomas at the BBC before he left to start PMC (in the UK). His former employer therefore became a purchaser of a huge number of his firm's speakers.
I built a pair of Curt Campbell Invictus mass loaded transmission line speakers: Invictus. Nothing special in the box other than bracing (and driver$). And apparently super important audiophile pillow stuffing! They sound awesome!
I like him a lot. However, I wish PS Audio would have not developed their own drivers this early on, and already had their speakers on sale for two years. Version 1 would have been significantly cheaper, and custom designed drivers would have been the project for the MkII versions. Getting dispersion, the crossover, and namely the unique tonal characteristics achieved is a tall order even when you have the luxury of picking and choosing from hundreds of off the shelf drivers. I would imagine custom made drivers dials in the thiele/small parameters to exactly what you need, but tonal qualities are more elusive. I could foresee a custom made driver appearing to be perfect for a specific job, but it just doesn't sound right. Then you're waiting for the production of another custom designed driver. Delays abound and no one gets speakers with such an approach. Version 1 would have been on sale for 2 years at about $6,000 cheaper. The MkII could then be offered to early adopters of version 1, if they wished to upgrade, at a 20% discount. Version 1 could then be sold to first time buyers under a certified used program and knock off 5%. And PS Audio could be upfront and say, "We want to do our hifi family right and get them an amazing speaker, and at a fair price. As speaker development and refinement marches on at PS Audio, we want to make sure everyone who purchases our speakers can remain up to date, if they so choose. And the best way to achieve this is by making a trade in/upgrade program seemless and at a discount."
I had a pair of IMF SPEAKERS, I loved the the sound, fast and they seemed to load the room differently than others box speakers, more like a dipole. Vandersteen uses a TL in its mid bass. I am building a ten foot pipe TL using three 8 inch drivers, with some magnepans, when finished will see if the Vandersteen 5 stay or go. Bass will be eq below 80hz.
I had a pair of IMF TLs years ago - my first floor standing speakers. Unfortunately my apt was burglarized and they were stolen. I replaced them with a pair of KM towers that had another interesting approach to loading the woofer. The cabinet was fairly large, also floor standing, and was filled with sulfur hexafluoride gas (SF6) which is about six times denser than air and supposedly was equivalent to making the volume of the enclosure six times larger. It would be interesting to hear Chris's comments about that design approach.
The quarter wave principle can be noted in vented tower speakers as well, in the form of an MLTL arrangement, because of their height. If any of you guys want to model horns/transmission lines, download HornResp. Steep learning curve, but a powerful program.
the TriTrix MTM Transmission Line Speaker DIY kit from PartsExpress is a fine sounding speaker especially with a few parts upgrades. And if you don't mind assembling it yourself, a great buy for the money. Also, the Seas "Thor" MTM Transmission Line Kit from Madisound is a premium version of a TL speaker kit.
After 5 designs Lynn Olson's Ariel 6e TL speaker has to be one of the best out there. Even tho I am an accomplished woodworker these were a difficult build and expensive. I built them in 2016 and even then with a mid-grade xover I had about $1800 in the project. But OMG the sound!! With separate 6ft TLs for each 5 1/2" woofer the bass extended down to where no sub was needed.
Actually, the most common transmission line design that many people will readily know is the Bose Wave radio. I like how P.S. Audio is going about using Chris in these videos. At first people were often complaining about him but now that he gets to show that he really knows his business it seems there's more respect in the comments. He'll never be as charismatic as Paul but that's not why he was hired.
@@mattuw82 Yes, something like that. It's very much Bose's patented take on a transmission line. It's quite short compared to a tranditional transmission line and also happens to be made of plastic. For what is essentially a radio it could do a good job but I cannot understand why Bose choose to then boost the bass electronically while also suppresing the treble to leave an over heavy sound that lacks detail.
@@johnr6168 Because without that order of curve, the Bose would sound saddle-backed in response to an even more detrimental effect, plus the wider market of non-audiophiles worship bass in their boogie coming from something small, so that was likely their remit for design from the thrusty marketing department. My two Porsche''s had dreadfully overblown sound and only worked with bass and treble pulled almost right back with rearward bias on the fader. Anything more and it was a claustrophobic cavern of bass emphasis.
My German T+A Criterion TCD 210 S, designed by Jochen Fabricius, are transmission-line speakers that are fitted with a very long transmission line (I have an picture of the internal construction I wish I could post). They have two 8.66" low frequency drivers, two 6.69" mid-range units in an D’Appolito configuration, and a 1" dome tweeter with waveguide. They are a 4 ohm speaker with a frequency range of 25 - 35,000 and sensitivity of 88db. To me, they have a natural sound, with powerful, high-quality bass and highly detailed imaging.
We in the UK still have company's that make kits of transmission line speakers in kit form IPL Acoustics also you can get second hand ones made by TDL Electronics those were also made here in the UK..:-)
I have the TDL Monitor and also Studio 3 in another room. They have an immense soundstage and effortless bass to below 20Hz. It's almost like having the musicians in the lounge with me.
I still have a pair of Meadowlark Kestrel transmission line speakers in my listening room. They were a great value and sound pretty darn good, although a little soft in the treble.
I almost bought a pair of Celestion 300 speakers, I though they were interesting because of their TML design. Some other speakers came on my path, still would want to try a pair of those 300 's
I still have a pair of IMF TLS-50/II in my collection, haven’t listen to them in over a decade, but they remind me of the polite 70s-80s British sound, like Rodgers LS3/5as which I had in the 80s. I had sold this pair numerous times to buddies who would want something else I had and I’d take them back in trade, they came back when I sold/traded my Tympani 1Ds. My Beveridge BSSS Model 2 had a similar easy not explosive signature. It was when 8 bought a pair of Altec 755as that I switched from my previous lov3 affair of electrostatics, I had 3 pairs of 57s all at the same time, had Sound Labs R1s and Beveridges, now it’s strictly into the Altec sound, especially the front loaded horns, like 821 and 211 bass cabinets.
infinity made the WTLC a very fine speaker which was a TLS. The WTLC with the Walsh tweeter had superior imaging and presence with an excellent mid-range cone covering all freq. A Simply Amazing speaker with a unique design from Arnie N.
A lot has to do with the Small-Thiele parameters of the speaker, particularly the Qts (if I remember correctly) which to a speaker is kind of like the compliancy of a phono cartridge. I think optimally, it should be between .45 and .6. You may get speakers outside that range to work, but you would really have to pay attention to the details such as stuffing, air losses, possibly the taper of the line. Also, whether it’s a folded or straight line would come into play. I used to know all this decades ago, but haven’t delved into speaker design for at least three decades, so I’m a bit rusty. Please forgive me.
The main principe of a TL is demping the resonance frequency of the woofer with an air column with a specific length and diameter. For technical details see The Rogers Domestic monitor.
My dad built a pair of TL speakers using KEFB139 LF drivers in an 89 inch damped tapered line. He stuffed it with Dr Bailey's long hair fibre wool ... they had a crossover at 200Hz at 12 dB / Oct and sounded magnificent ... better than the commercial Redford R50 model
Here's an idea: Why don't you make a pair of them? Falcon Acoustics have re-created the original B139, B110 and T27. Their version of the B139 has improved power handling and longer excursion. I'd say it's a fine COVID project involving plenty of woodworking and lots of lambswool and done right, could complement your listening room experiences. Might well be a baseline comparing 1960s technology with the current one, 60 years later, when your loudspeakers are finalized.
The "giant pyramid" design Chris mentions at the end is a Voigt pipe or Voigt tube design, invented in the 1930's by Paul Voigt. They're generally thought to be the most efficient design of speaker though they do look quite strange. With newer damping technologies and materials available today they can sound amazing if done right.
i owned TDL Reference Standards, very large and I chose them over B&Ws, Wilson Watt puppies at the time bought them from Simon in at Stereo Store in Chicago.
I am making a classic /straight T-line with a 12" woofer. The cabinet/waveguide is now at 240 lenght and is around 155 liters. Someone i know say i should try to make the T-line closer to VAS of the driver(85 Liter) Should i worry about VAS when making a classic T-line? I dont se how since the line area should equal or exceed slighty the cone area of the driver used and the line length should be 1/4 wavelength tuned to the resonant frequency of the chosen speaker. Can someone help me out? Thx
I don't get the size argument against TL speakers. There are plenty of other large speakers using conventional ported design. In any case, I adore my B139-based TLs. Big, open bass that breathes and sounds pretty natural to me.
I once asked Vince Bruzzese of Totem speakers if his floorstanding designs were transmission line. He looked at me like I just farted and said... "absolutely not... transmission line speakers are slo-o-o-o-o-o-w-w-w-w". Then he went on to extol the virtues of his aluminum "beaks" sitting atop his speakers.
I used to have Transmission Line speakers. I don't think the company TDL exists any more; I used to have TDL RTL2 speakers and really enjoyed them, the RTL3 I thought were even better. They were enormous though; not very tall or wide, but exceptionally deep...I would say 3-4x deeper than the typical floorstanding speaker of the time.
TDL folded up in about 1995. John Wright, one of the founders died soon after. The RTL range were reflex/transmission lines. They replaced the earlier but more costly trandtional transmission lines range, - the Studios plus a couple of others models. They were even deeper. I have the Monitors which are 47cm deep, 30cm wide and 115cm high. In other words, big, but very nice to look at especially with the grills on. Their sound is awesome.
I’ve heard many a claim the rtl2 are preferred over the 3’s due to overall delivery and slightly deeper bass, I really would like to see the difference in “Original TL” against the “Reflex TL” hmmmm 🤔
I instantly regretted selling mine, the RTL-2's. My wife nagged me for less obtrusive speakers. As "Joe" at Huddersfield Hi-Fi referred to them as being "creamy" which was a perfect analogy to describe them. They were best suited to jazz and acoustic I found. The vinyl wrap just set them off nicely. I still miss them after nearly 30 years.
The TDL Reference Standard, as highly rated by UK's Noel Keywood in Hi-fi World in around the early 1990's was a remarkable swan-song achievement. Dual racetrack bass units in what was a colossal enclosure. I often wonder how many were made.
LS50 "Meta" addresses the back wave in a different way. Very innovative to address mid and high frequency issues but unlikely to provide the same benefits in the bass region.
A legit transmission line is in effect an acoustic waveguide that requires a much larger cabinet than a sealed or ported box design. The LS50 driver in TL would require a cabinet the size of a large floor-standing design.
Thanks for the clarification. I saw a response referencing Klipsch LaScalas being transmission line. Would the folded bass horn fit the design criteria?
Yes, I remember the t-linespeakers website. I recall some of the math on there being old/wrong, though it’s been many years since I looked into it . I sometimes forget to mention things speaking off the cuff. Things like david mcbeans freeware horn respone program does a great job or things like AKABAK for more complex things.
After being much abused by DIYers and unscrupulous small manufacturers declining to pay his very modest licensing fees , I think Martin withdrew distribution and support for his MathCad worksheets. There are literally dozens of excellent enclosures designed using his worksheets - before my recent retirement from active building I constructed more than a few prototypes modelled by others, including many that utilized small “Full Range” drivers of the type to which Chris refers. In fact, I’m still living with two pairs of MLTL (mass loaded transmission line) - one a single driver system, and the other a 2 way MTM.
@@cbrunhaver Fascinating perspective from one who clearly has researched the back history on TL designs. John Wright (over here in England) was one of our handful of unsung heroes in hi-fi; both studio and commercially. Bud Fried identified this and took to setting it all into motion. PS Audio would surely make an ultimate version of this loading one day?
There was a subwoofer demonstrated, or, offered in the 70's that was tagged "The Coffin". That due to it's resemblance to a real coffin in size. It used two KEF B139's, one for each channel. There were two tunnels folded back once. One tunnel for each speaker. I can't rememeber if it was ported. It was a subwoofer therefore the external active crossover had to be rolled off at a 24db slope at or below 80Hz. It doubled as a coffee table and was meant, and demonstrated, positioned somewhere more towards the middle of the room not against a wall or corner. I only heard it once but remember being impressed.
Chris is a brain on legs. I'm surprised he hasn't built a rocket ship yet. Transmission lines speakers are fascinating because it seems like the bass comes from nowhere.
@@KingOath That is so true! Just read a white paper that confers such between our hearing faculty and the relevance of subjective high-end audio performance from a world authority on the sciences within this field.
@@britishcomposers Man, the amount of filters your brain adds to your senses is incredible, people just don’t recognize this is going on or give it enough credit. What you perceive has little to do with what’s actually happening and a hell of a lot to do with your personal life experience and personal preferences as a result. I’m no longer interested in being told by the Hifi community what I should like and what is correct, I stopped caring about their rules and started enjoying my music the way I felt like doing so and I’ve never felt so connected to the music.
@@KingOath It's always about the music for me and clawing-back as much of what I enjoy from attending recitals, gigs, and concerts when back at home. Such a tall order is never fully realised, but I baulk at the obsession over statistics being so 'key' to some engineers when it is the brain's processing with added bias from previous experiences that inform how far an experience can actually go. Great approach you take.
Some day soon somebody is going to come up with a non resonating structural composite material that can also be 3d printed. At that moment speaker design is going to explode with possibilities.
For every day that passes, people are spending money on new speakers without the benefit of even considering the PSA variant. I love these videos! Chris obviously is very knowledgeable and loves what he does, but lets put the pencil down and get to making some money er.. music.....
TQWT also has crushingly low sensitivity for any given driver/cabinet size and f3 combination. The trade off is HUGE. Why do a dual 6.5" MTM with a 26hz f3 at 84dB when one could employ a critically damped vented alignment in the EXACT same enclosure dimensions and net another 5-7dB of broadband sensitivity while "only" having an f3 of the low 40hz range? That's tantamount to doubling/quadrupling your amp output wattage for a few hz down low. A trade most would happily make. Oh and that QWT will never make bass as well as even a moderately sized subwoofer, properly positioned and time aligned.
Good video. Let me add that 1/4-wavelength effects are far-reaching. They can be applied to transmission lines and antennas in electronics... and also apply to light/optics!
Look, I want some damn PS Audio speakers in my music room now. The thing is I see none to buy/for sale? ZERO / NADA / ZILCH - NOW PAUL or my money could get locked up by the wife....
"Possibly the best solution between ported and sealed speakers". Yes it is. (All this was very generic). Things have moved a lot since then. We can model TLs pretty accurately now. The results put everything else to shame. The only issue is speaker volume.
Well cube audio use a loaded horn transmission line what is similar to what he's saying but I don't think it's the same. Is a lot of speaker kits that use transmission line damping materials you have to use numerous types. transmission line is a better thing but more complex to build
Ports and transmission lines might sound subjectively good, but it runs counter to the fact most claim they're all about "purity of sound", and they are "merely attempting to hear the recording as it exists." Ports and transmission lines cause you to hear delayed reinforcement waves. The phase alignment results suffer. Eeek ;)
Often simpler is better. A speaker with a flat frequency response and extended bass might not actually sound good due to too slow decay and distortion. I've never found transmission line bass to sound good, but maybe I missed something.
@@petersouthernboy6327 I didn't say distortion is due to transmission line. The point is that many speakers are optimized more towards making much bass than making clean bass. The transmission line design introduces a delayed ring. The only approach of a woofer design that is time-accurate is the sealed enclosure. I very much prefer a sealed cabinet, possibly with servo feedback to further enhance the decay and minimize distortion incl. anything related to damping issues, thermal coil coefficient issues, and voice coil motion linearity. But surely a servo subwoofer is much more complex as it involves synergic design between the speaker and amp.
Jerry Rutten - I think that is more an issue for a full range driver with a whizzer cone (Lowther). If you’ve correctly tuned your TL design, your standing wave resonance range is going to be filtered out by your crossover.
It’s always annoyed me that the Powersoft IPAL system never gained more widespread OEM use. And they never made it directly available to consumers on the components market.
IMF TLS80's were the absolute best sounding speakers I have ever owned. Tympani drums and cathedral organs were right there in your living room.....best natural uncompressed bass ever!
Had my PMC FB1s for over 15 years and they still sound superb!
PMC does TL absolutely right. Their midrange and mid bass are superb and clean because the line is designed properly and dampened correctly. Few speakers can match the clarity and extension. Most manufacturers just can’t stomach the time, effort and cost to build the cabinets. Still love my GB1i’s!!
I actually knew Bud Fried. A client of mine in public accounting has a son that bought his company. Bud was often there consulting on design. He was an interesting guy to say the least. A real legend in the business
Still rocking the pair of TL speakers I designed and built about 40 years ago. I had to re-foam the woofers about 10 years ago. I recall spending at least as much time tuning, using some equipment I borrowed from work, them as I did building them. I was just out of college and told my parents I wanted 4 sheets of 3/4 in. particle board for Christmas. When I made it home for the holiday, fired up my dad's table saw and cut all the pieces and packed that into my car and drove ~1000 miles back home. Then assembled the parts in my apartment. A few years later, I made a spur of the moment drive from the SF Bay Area to Seattle to grab 4 - 10" TL drivers from Speaker Lab, I think that was the last 4 they had in stock. These replace the original 8" drivers I originally used. All the crossover coils were hand wound out of 14AWG enameled wire. They are large, 2 feet square and 4 feet tall, sized for the 4x8 foot sheet of particle board.
Thanks Chris. Transmission lines got me into speaker building. There was one at the hi-fi shop in Pullman where I went to school. It would shake the tiles in the suspended ceiling which was totally amazing to me. I've built a few over the years but am more of a ported box guy these days, mainly due to the more reasonable enclosure size.
Always learn something useful when Chris and Paul share their lunch conversation. I have been hearing folks rave about some diyaudio TL speakers. Good to know something about them.
I built my transmission lines with the B139 he mentions-46 years ago- they have just had a x-over upgrade.
That speaks for itself! Continued usage of a most successful and highly relevant enclosure design.
This was a very interesting episode. Thanks!
Thanks for the talk.👍
I remember meeting Irving Fred at in New Jersey Audio salon over 45 years ago when I was looking for a new pair of speakers. I was never a giant fan of IMF. I wound up buying Dahlquist DQ-10's. Never regretted that purchase for one minute. I would've never been happy with Fried boxes Not after hearing the Dahlquists.
You guys keep up the great job you're doing with detailing us on speaker design.
John Wright designed the transmission-line designs of IMF. Bud brokered the marketing deal by setting IMF (and John Wright) up in the UK and importing/distributing them. TL designs can fail terribly in the wrong room acoustic. The Dahlquist was and is still regarded highly by engineers over here too.
I first heard Rega ELA transmission lines in the early 90's using the Naim Nait and was amazed at how natural and smooth bass notes were over a variety of frequencies. Not 'clumpy' bass kicks and booming in one area, they just 'breathe' music in a way I've never found before. Now I'm using an IPL kit and very happy. All things have pros and cons and it's down to individual tastes but I love TLs!
I really enjoy Chris's insights on speaker design. I still have my DCM TF600 speakers, an interesting design with transmission line bass, coaxial design with the tweeter mounted over the mid bass driver and two rear firing tweeters working at a lower volume. They have a very natural sound with a holographic midrange. How the heck DCM got this design to work is a mystery. lol
Dcm 600's are hidden jewels!
Thanks for taking the time to make this
I have TDL RTL 4 since the mid 90' and still rocking.
The RTL range are actually reflex/transmission line but still good. If you ever get the chance to hear their earlier Studio 3, Studio 4, Monitor, or Reference Standard, then do! They are true transmission lines.
I have worked my way up from RTL 2's, RTL 3's, to Studio 1's, the better version with the rebated cones. They don't kick butt like the Tannoy DC3000's in the living room, but with the volume low, as I have to have it in the evenings, when my wife is in bed, they loose none of the bass. Like the Tannoy's, they'll probably see me out :).
@@johnr6168 I used to sell TDL in Chelsea 35-years ago, (not the Reference sadly - too big for the dem room) but they were each superb.
I have the Meadowlark Kestrel. They are astounding sounding and really getting them placed properly is a big part. The base reproduction belies their size. Time coherent on top of that. Just amazing.
Cool subject and nice to hear that Chris is also following the single driver developments that are mainly self build speakers. Now that we are talking about transmission lines, just for the heck of it it would be great to get a talk about Karlsson resonators. Can they be considered wide band transmission lines? can the colouring be mitigated? I have always been fascinated by them.
I like this guy keeping it real. 👍
I worked with Pete Thomas at the BBC before he left to start PMC (in the UK). His former employer therefore became a purchaser of a huge number of his firm's speakers.
I built a pair of Curt Campbell Invictus mass loaded transmission line speakers: Invictus. Nothing special in the box other than bracing (and driver$). And apparently super important audiophile pillow stuffing! They sound awesome!
Chris is the right guy for the job. His knowledge in all things speakers is quite detailed.
I like him a lot. However, I wish PS Audio would have not developed their own drivers this early on, and already had their speakers on sale for two years.
Version 1 would have been significantly cheaper, and custom designed drivers would have been the project for the MkII versions.
Getting dispersion, the crossover, and namely the unique tonal characteristics achieved is a tall order even when you have the luxury of picking and choosing from hundreds of off the shelf drivers.
I would imagine custom made drivers dials in the thiele/small parameters to exactly what you need, but tonal qualities are more elusive. I could foresee a custom made driver appearing to be perfect for a specific job, but it just doesn't sound right. Then you're waiting for the production of another custom designed driver. Delays abound and no one gets speakers with such an approach.
Version 1 would have been on sale for 2 years at about $6,000 cheaper. The MkII could then be offered to early adopters of version 1, if they wished to upgrade, at a 20% discount. Version 1 could then be sold to first time buyers under a certified used program and knock off 5%.
And PS Audio could be upfront and say, "We want to do our hifi family right and get them an amazing speaker, and at a fair price. As speaker development and refinement marches on at PS Audio, we want to make sure everyone who purchases our speakers can remain up to date, if they so choose. And the best way to achieve this is by making a trade in/upgrade program seemless and at a discount."
I had a pair of IMF SPEAKERS, I loved the the sound, fast and they seemed to load the room differently than others box speakers, more like a dipole. Vandersteen uses a TL in its mid bass.
I am building a ten foot pipe TL using three 8 inch drivers, with some magnepans, when finished will see if the Vandersteen 5 stay or go. Bass will be eq below 80hz.
I own dual transmission line speakers in a MTM arrangement by Role Audio. Love them.
I could listen to Chris talking all day long such a good approach to explaining the difficult but fascinating stuff
I had a pair of IMF TLs years ago - my first floor standing speakers. Unfortunately my apt was burglarized and they were stolen. I replaced them with a pair of KM towers that had another interesting approach to loading the woofer. The cabinet was fairly large, also floor standing, and was filled with sulfur hexafluoride gas (SF6) which is about six times denser than air and supposedly was equivalent to making the volume of the enclosure six times larger. It would be interesting to hear Chris's comments about that design approach.
Are you talking about Cerwin Vega's S-1 ''Thermo Vapor'' technology?
The quarter wave principle can be noted in vented tower speakers as well, in the form of an MLTL arrangement, because of their height.
If any of you guys want to model horns/transmission lines, download HornResp. Steep learning curve, but a powerful program.
the TriTrix MTM Transmission Line Speaker DIY kit from PartsExpress is a fine sounding speaker especially with a few parts upgrades. And if you don't mind assembling it yourself, a great buy for the money. Also, the Seas "Thor" MTM Transmission Line Kit from Madisound is a premium version of a TL speaker kit.
After 5 designs Lynn Olson's Ariel 6e TL speaker has to be one of the best out there. Even tho I am an accomplished woodworker these were a difficult build and expensive. I built them in 2016 and even then with a mid-grade xover I had about $1800 in the project. But OMG the sound!! With separate 6ft TLs for each 5 1/2" woofer the bass extended down to where no sub was needed.
Troels has some designs that involve either a TL woofer and stuffed port mid (separate enclosure) or a different TL for the mid box.
A great resource he is on loudspeaker design. I must see what he's been up to lately.
Actually, the most common transmission line design that many people will readily know is the Bose Wave radio.
I like how P.S. Audio is going about using Chris in these videos. At first people were often complaining about him but now that he gets to show that he really knows his business it seems there's more respect in the comments. He'll never be as charismatic as Paul but that's not why he was hired.
This is true! I think in the case of the Bose Wave Radio they use transmission lines to make a dual chamber band pass.
@@mattuw82 Yes, something like that. It's very much Bose's patented take on a transmission line. It's quite short compared to a tranditional transmission line and also happens to be made of plastic. For what is essentially a radio it could do a good job but I cannot understand why Bose choose to then boost the bass electronically while also suppresing the treble to leave an over heavy sound that lacks detail.
@@johnr6168 Because without that order of curve, the Bose would sound saddle-backed in response to an even more detrimental effect, plus the wider market of non-audiophiles worship bass in their boogie coming from something small, so that was likely their remit for design from the thrusty marketing department. My two Porsche''s had dreadfully overblown sound and only worked with bass and treble pulled almost right back with rearward bias on the fader. Anything more and it was a claustrophobic cavern of bass emphasis.
My German T+A Criterion TCD 210 S, designed by Jochen Fabricius, are transmission-line speakers that are fitted with a very long transmission line (I have an picture of the internal construction I wish I could post). They have two 8.66" low frequency drivers, two 6.69" mid-range units in an D’Appolito configuration, and a 1" dome tweeter with waveguide. They are a 4 ohm speaker with a frequency range of 25 - 35,000 and sensitivity of 88db. To me, they have a natural sound, with powerful, high-quality bass and highly detailed imaging.
We in the UK still have company's that make kits of transmission line speakers in kit form IPL Acoustics also you can get second hand ones made by TDL Electronics those were also made here in the UK..:-)
I've built a pair of ipl.
They sound great
@@robertt6430 Great Blessings...:-)
I have the TDL Monitor and also Studio 3 in another room. They have an immense soundstage and effortless bass to below 20Hz. It's almost like having the musicians in the lounge with me.
@@johnr6168 Yes ! that is what i would say about them too...Happy listening and have a great new year..:-)
I still have a pair of Meadowlark Kestrel transmission line speakers in my listening room. They were a great value and sound pretty darn good, although a little soft in the treble.
I almost bought a pair of Celestion 300 speakers, I though they were interesting because of their TML design. Some other speakers came on my path, still would want to try a pair of those 300 's
I still have my homebuilt knock off IMF Mark IVs. I was never a big fan of the T27 but they were a fun 70s project.
I still have a pair of IMF TLS-50/II in my collection, haven’t listen to them in over a decade, but they remind me of the polite 70s-80s British sound, like Rodgers LS3/5as which I had in the 80s. I had sold this pair numerous times to buddies who would want something else I had and I’d take them back in trade, they came back when I sold/traded my Tympani 1Ds. My Beveridge BSSS Model 2 had a similar easy not explosive signature. It was when 8 bought a pair of Altec 755as that I switched from my previous lov3 affair of electrostatics, I had 3 pairs of 57s all at the same time, had Sound Labs R1s and Beveridges, now it’s strictly into the Altec sound, especially the front loaded horns, like 821 and 211 bass cabinets.
Master class thanks
infinity made the WTLC a very fine speaker which was a TLS. The WTLC with the Walsh tweeter had superior imaging and presence with an excellent mid-range cone covering all freq. A Simply Amazing speaker with a unique design from Arnie N.
Alta speakers...Excellent transmission line speakers that are worth a listen.
A lot has to do with the Small-Thiele parameters of the speaker, particularly the Qts (if I remember correctly) which to a speaker is kind of like the compliancy of a phono cartridge. I think optimally, it should be between .45 and .6. You may get speakers outside that range to work, but you would really have to pay attention to the details such as stuffing, air losses, possibly the taper of the line. Also, whether it’s a folded or straight line would come into play. I used to know all this decades ago, but haven’t delved into speaker design for at least three decades, so I’m a bit rusty. Please forgive me.
The main principe of a TL is demping the resonance frequency of the woofer with an air column with a specific length and diameter. For technical details see The Rogers Domestic monitor.
This is awesome.
My dad built a pair of TL speakers using KEFB139 LF drivers in an 89 inch damped tapered line. He stuffed it with Dr Bailey's long hair fibre wool ... they had a crossover at 200Hz at 12 dB / Oct and sounded magnificent ... better than the commercial Redford R50 model
Here's an idea: Why don't you make a pair of them? Falcon Acoustics have re-created the original B139, B110 and T27. Their version of the B139 has improved power handling and longer excursion. I'd say it's a fine COVID project involving plenty of woodworking and lots of lambswool and done right, could complement your listening room experiences. Might well be a baseline comparing 1960s technology with the current one, 60 years later, when your loudspeakers are finalized.
Love my IMFtls 80 mark1,s.They go low,17 hz.
Anthony Gallo Classico CL4s......transmission line with rear slot....wonderful sound top to bottom
The "giant pyramid" design Chris mentions at the end is a Voigt pipe or Voigt tube design, invented in the 1930's by Paul Voigt. They're generally thought to be the most efficient design of speaker though they do look quite strange. With newer damping technologies and materials available today they can sound amazing if done right.
i owned TDL Reference Standards, very large and I chose them over B&Ws, Wilson Watt puppies at the time bought them from Simon in at Stereo Store in Chicago.
What kind of microphone are you using to record these interviews? I find myself looking around as if someone's in my room from the background chatter.
I have a pair of Cain & Cain Abby's on Stellar S300 and sounds great
I am making a classic /straight T-line with a 12" woofer. The cabinet/waveguide is now at 240 lenght and is around 155 liters. Someone i know say i should try to make the T-line closer to VAS of the driver(85 Liter) Should i worry about VAS when making a classic T-line? I dont se how since the line area should equal or exceed slighty the cone area of the driver used and the line length should be 1/4 wavelength tuned to the resonant frequency of the chosen speaker. Can someone help me out? Thx
I don't get the size argument against TL speakers. There are plenty of other large speakers using conventional ported design. In any case, I adore my B139-based TLs. Big, open bass that breathes and sounds pretty natural to me.
Voigt pipe is a transmission line right?
I have a pair of JMLab Daline 6.1, they sound awesome!
These lunch-questions with Chris are very interestring but way too short ;-)
Transmission line is best IMO.
Btw, I think that B&W "Snail" is called the nautilus.
Can you comment on synergy horn speakers?
I once asked Vince Bruzzese of Totem speakers if his floorstanding designs were transmission line.
He looked at me like I just farted and said... "absolutely not... transmission line speakers are slo-o-o-o-o-o-w-w-w-w". Then he went on to extol the virtues of his aluminum "beaks" sitting atop his speakers.
Strange, because Roger Sanders uses transmission line bass for speed (and other reasons too) to match the electrostatic panel.
I used to have Transmission Line speakers. I don't think the company TDL exists any more; I used to have TDL RTL2 speakers and really enjoyed them, the RTL3 I thought were even better. They were enormous though; not very tall or wide, but exceptionally deep...I would say 3-4x deeper than the typical floorstanding speaker of the time.
TDL folded up in about 1995. John Wright, one of the founders died soon after. The RTL range were reflex/transmission lines. They replaced the earlier but more costly trandtional transmission lines range, - the Studios plus a couple of others models. They were even deeper. I have the Monitors which are 47cm deep, 30cm wide and 115cm high. In other words, big, but very nice to look at especially with the grills on. Their sound is awesome.
I’ve heard many a claim the rtl2 are preferred over the 3’s due to overall delivery and slightly deeper bass, I really would like to see the difference in “Original TL” against the “Reflex TL” hmmmm 🤔
I instantly regretted selling mine, the RTL-2's. My wife nagged me for less obtrusive speakers. As "Joe" at Huddersfield Hi-Fi referred to them as being "creamy" which was a perfect analogy to describe them. They were best suited to jazz and acoustic I found. The vinyl wrap just set them off nicely. I still miss them after nearly 30 years.
The TDL Reference Standard, as highly rated by UK's Noel Keywood in Hi-fi World in around the early 1990's was a remarkable swan-song achievement. Dual racetrack bass units in what was a colossal enclosure. I often wonder how many were made.
Interesting interview and topic. Thanks! Is the new KEF LS50 Meta transmission line?
No.
LS50 "Meta" addresses the back wave in a different way. Very innovative to address mid and high frequency issues but unlikely to provide the same benefits in the bass region.
A legit transmission line is in effect an acoustic waveguide that requires a much larger cabinet than a sealed or ported box design. The LS50 driver in TL would require a cabinet the size of a large floor-standing design.
Thanks for the clarification. I saw a response referencing Klipsch LaScalas being transmission line. Would the folded bass horn fit the design criteria?
Michael Westerlund - Klipsch LaScala (and Klipschorn) are NOT transmission lines. They are folded horns - completely different design and outcome.
there is and UK company called Castle who make tml speakers
Here's me expecting a talk about cables used on power poles 🤣
I made a T-line box for my subwoofer. Wow.
I would suggest mention of Martin J. King, his heuristics optimized MathCad worksheet models, and the information that he provides on his website.
Yes, I remember the t-linespeakers website. I recall some of the math on there being old/wrong, though it’s been many years since I looked into it . I sometimes forget to mention things speaking off the cuff. Things like david mcbeans freeware horn respone program does a great job or things like AKABAK for more complex things.
After being much abused by DIYers and unscrupulous small manufacturers declining to pay his very modest licensing fees , I think Martin withdrew distribution and support for his MathCad worksheets. There are literally dozens of excellent enclosures designed using his worksheets - before my recent retirement from active building I constructed more than a few prototypes modelled by others, including many that utilized small “Full Range” drivers of the type to which Chris refers. In fact, I’m still living with two pairs of MLTL (mass loaded transmission line) - one a single driver system, and the other a 2 way MTM.
@@cbrunhaver Fascinating perspective from one who clearly has researched the back history on TL designs. John Wright (over here in England) was one of our handful of unsung heroes in hi-fi; both studio and commercially. Bud Fried identified this and took to setting it all into motion. PS Audio would surely make an ultimate version of this loading one day?
In the Netherlands we had very good TL speakers from Hans Baan round 1980 but not wife frendly becourse very big
There was a subwoofer demonstrated, or, offered in the 70's that was tagged "The Coffin". That due to it's resemblance to a real coffin in size. It used two KEF B139's, one for each channel. There were two tunnels folded back once. One tunnel for each speaker. I can't rememeber if it was ported. It was a subwoofer therefore the external active crossover had to be rolled off at a 24db slope at or below 80Hz. It doubled as a coffee table and was meant, and demonstrated, positioned somewhere more towards the middle of the room not against a wall or corner. I only heard it once but remember being impressed.
Bill Kenney That would have been one of of Bud’s signature designs - Model H.
www.t-linespeakers.org/classics/friedH/fried_H.html
Yes lmf were magnificent. Anyway l prefer trasmissione line, over bass reflex, the back air produced by the woofer Is treated much more Naturally.
Chris is a brain on legs. I'm surprised he hasn't built a rocket ship yet. Transmission lines speakers are fascinating because it seems like the bass comes from nowhere.
That’s right. It’s not about quantifiable performance, it’s about the subjective experience of listening to them.
@@KingOath That is so true! Just read a white paper that confers such between our hearing faculty and the relevance of subjective high-end audio performance from a world authority on the sciences within this field.
@@britishcomposers Man, the amount of filters your brain adds to your senses is incredible, people just don’t recognize this is going on or give it enough credit. What you perceive has little to do with what’s actually happening and a hell of a lot to do with your personal life experience and personal preferences as a result. I’m no longer interested in being told by the Hifi community what I should like and what is correct, I stopped caring about their rules and started enjoying my music the way I felt like doing so and I’ve never felt so connected to the music.
@@KingOath It's always about the music for me and clawing-back as much of what I enjoy from attending recitals, gigs, and concerts when back at home. Such a tall order is never fully realised, but I baulk at the obsession over statistics being so 'key' to some engineers when it is the brain's processing with added bias from previous experiences that inform how far an experience can actually go. Great approach you take.
Some day soon somebody is going to come up with a non resonating structural composite material that can also be 3d printed. At that moment speaker design is going to explode with possibilities.
They already have this MeTa material at KEF speaker
For every day that passes, people are spending money on new speakers without the benefit of even considering the PSA variant. I love these videos! Chris obviously is very knowledgeable and loves what he does, but lets put the pencil down and get to making some money er.. music.....
Given this gentleman's age, his knowledge is staggering. But can he listen? We'll find out.
You might enjoy watching the video of my Fried satellite and subwoofer transmission lines.
😊
TQWT also has crushingly low sensitivity for any given driver/cabinet size and f3 combination. The trade off is HUGE. Why do a dual 6.5" MTM with a 26hz f3 at 84dB when one could employ a critically damped vented alignment in the EXACT same enclosure dimensions and net another 5-7dB of broadband sensitivity while "only" having an f3 of the low 40hz range? That's tantamount to doubling/quadrupling your amp output wattage for a few hz down low. A trade most would happily make.
Oh and that QWT will never make bass as well as even a moderately sized subwoofer, properly positioned and time aligned.
Good video. Let me add that 1/4-wavelength effects are far-reaching. They can be applied to transmission lines and antennas in electronics... and also apply to light/optics!
Next lunch topic: Karlson Couplers
Look, I want some damn PS Audio speakers in my music room now. The thing is I see none to buy/for sale? ZERO / NADA / ZILCH - NOW PAUL or my money could get locked up by the wife....
"Possibly the best solution between ported and sealed speakers". Yes it is. (All this was very generic). Things have moved a lot since then. We can model TLs pretty accurately now. The results put everything else to shame. The only issue is speaker volume.
Only for the wives, if speaking about cabinet enclosure volume.
Try Trolls G
Well cube audio use a loaded horn transmission line what is similar to what he's saying but I don't think it's the same.
Is a lot of speaker kits that use transmission line damping materials you have to use numerous types. transmission line is a better thing but more complex to build
For damping: Meta materials are the new way to go...
Ports and transmission lines might sound subjectively good, but it runs counter to the fact most claim they're all about "purity of sound", and they are "merely attempting to hear the recording as it exists."
Ports and transmission lines cause you to hear delayed reinforcement waves. The phase alignment results suffer. Eeek ;)
Bose.
Often simpler is better. A speaker with a flat frequency response and extended bass might not actually sound good due to too slow decay and distortion. I've never found transmission line bass to sound good, but maybe I missed something.
How does a Transmission Line “introduce” distortion, exactly ?
@@petersouthernboy6327 Chris said an uneven load on the driver, depending on frequency.
@@petersouthernboy6327 I didn't say distortion is due to transmission line. The point is that many speakers are optimized more towards making much bass than making clean bass. The transmission line design introduces a delayed ring. The only approach of a woofer design that is time-accurate is the sealed enclosure. I very much prefer a sealed cabinet, possibly with servo feedback to further enhance the decay and minimize distortion incl. anything related to damping issues, thermal coil coefficient issues, and voice coil motion linearity. But surely a servo subwoofer is much more complex as it involves synergic design between the speaker and amp.
Jerry Rutten - I think that is more an issue for a full range driver with a whizzer cone (Lowther). If you’ve correctly tuned your TL design, your standing wave resonance range is going to be filtered out by your crossover.
It’s always annoyed me that the Powersoft IPAL system never gained more widespread OEM use. And they never made it directly available to consumers on the components market.
A sealed tube is no longer a Transmission Line. Ridiculous.
I've never heard a TL speaker I like. Too much expense for too little possible return even when done right.
It's supposed to give the widest and flattest response from the driver installed, but it takes alot of space and will be heavy
Not a good video
The guy looks like Woody Harrelson. #
PMC Fenestria , awesome 60K$ speakers! Dismantled Wilson Sasha V… In every point…