In 1977 I built a pair of transmission line loudspeakers, similar to the famous Webb design, but somewhat larger. When I went to graduate school in 1980, they were too bulky to bring along, so I sold them. Now, both myself and a friend from those days want to build a couple of pairs. So I'd like to locate a copy of the plans.
With that as an intro, does anyone here have a catalog or plans from the company that produced the kit? It was called Accurate Sound, and was at 1213 M Street, Lincoln NE 68508. Below, I've reproduced a copy of an advertisement of theirs, from the January 1977 issue of Audio Amateur, page 49.
Does anyone here recognize this, or have an old catalog or plans?
Cheers,
Bruce
With that as an intro, does anyone here have a catalog or plans from the company that produced the kit? It was called Accurate Sound, and was at 1213 M Street, Lincoln NE 68508. Below, I've reproduced a copy of an advertisement of theirs, from the January 1977 issue of Audio Amateur, page 49.
Does anyone here recognize this, or have an old catalog or plans?
Cheers,
Bruce
I saw that ad when my AA arrived.
Historical interest or you want to build one of these antiques?
dave
Historical interest or you want to build one of these antiques?
dave
I want to build one of these again, and so does a friend of mine from that era. Falcon Acoustics UK is still manufacturing the KEF drivers, using improved adhesives, magnets and insulation. The ones I built were the tallest ones shown in the advert (center back) but with a Coles dome tweeters rather than the Decca ribbon shown in the advert.
Why? I wouldn’t builkd any TL from before the time of, and modeled with a modern TL modeler by someone who knows what they are doing..
The only reason would be nostalgia.
dave
The only reason would be nostalgia.
dave
This is not what you are asking for, but these 2 designs (Roger's Monitor and Atkins State of the Art) originally used the same speaker configuration. Both were excellent speakers. The bass of the State of the Art was clearly more extended on the low side.
I don't agree with @planet10 about the modelling. I modelled both in Hornresp, and the response was awful. Not anything I would invest my time in to build. But they sounded awesome.
The only flaw in the design might be that they use a passive crossover. But then again, the imperfect crossover might have contributed to the excellent sound.
I don't agree with @planet10 about the modelling. I modelled both in Hornresp, and the response was awful. Not anything I would invest my time in to build. But they sounded awesome.
The only flaw in the design might be that they use a passive crossover. But then again, the imperfect crossover might have contributed to the excellent sound.
Can't speak for Dave, but I'd guess the modeling he was referring to meant the work of M.J. King. Transmission theory from then to now has changed dramatically, and for the better. (This from someone who, years ago, built a trans line based on Bailey's now disproved theories using those same KEF drivers plus a Coles super tweeter.)
One can not warn enough about these old speaker constructions, using KEF drivers. May them be KEF, TDL or other constructions. They had a legendary reputation, even at the time they were quite new, around 1985.
At that time the average speaker people were used and able to hear to, were really bad in every aspect. Also, hardly anyone had a high quality source, most record players still using crystal pickups.
So when you came from that standard to someone, may it be private or shop, who used a good record player, a MM pickup, a capable amp and such speakers, you were blown away. You never had heard such high and low frequency extention from any audio installation before.
If you, like me, had been spolied with rare large HIFI speakers from JBL, Electro Voice or Altec, to name a few, this stuff usually based around the KEF B139 didn't impress you at all. People created the myth of the "British sound" to justify this kind of reproduction and give it some noblesse. On such "British" chains you always heard the same demo music, usuall not life rock recordings like the stones, but more esotheric stuff.
On the other side, at the mentioned JBL, EV and Altec speaker, you could throw any dynamic, modern music and start to dance.
The acoustic memory is very limited. We usually don't remember the real sound from decades ago, but some feelings we had when we listened to it. The same speaker, auditioned today, will be a huge disapointment. Not only the cult stuff around KEF, but also the US-American power gear.
We have much better source material and amps today, at a price point lower than the cost of a high quality MM pickup of that time. The speakers had to improve too and did. So our basic quality level of audio reproduction is much higher today.
My advice would be to use the space and size of the 80's for a DIYS speaker, if you are so lucky to have the room, but never use the plans from that time. Go active from the start and build some kit with a reputation. You will have an incredible result from todays material at very fair prices. Hunting for vintage drivers is a different hobby, not about absolute quality. You can compare it to collecting Edison wax recordings...
At that time the average speaker people were used and able to hear to, were really bad in every aspect. Also, hardly anyone had a high quality source, most record players still using crystal pickups.
So when you came from that standard to someone, may it be private or shop, who used a good record player, a MM pickup, a capable amp and such speakers, you were blown away. You never had heard such high and low frequency extention from any audio installation before.
If you, like me, had been spolied with rare large HIFI speakers from JBL, Electro Voice or Altec, to name a few, this stuff usually based around the KEF B139 didn't impress you at all. People created the myth of the "British sound" to justify this kind of reproduction and give it some noblesse. On such "British" chains you always heard the same demo music, usuall not life rock recordings like the stones, but more esotheric stuff.
On the other side, at the mentioned JBL, EV and Altec speaker, you could throw any dynamic, modern music and start to dance.
The acoustic memory is very limited. We usually don't remember the real sound from decades ago, but some feelings we had when we listened to it. The same speaker, auditioned today, will be a huge disapointment. Not only the cult stuff around KEF, but also the US-American power gear.
We have much better source material and amps today, at a price point lower than the cost of a high quality MM pickup of that time. The speakers had to improve too and did. So our basic quality level of audio reproduction is much higher today.
My advice would be to use the space and size of the 80's for a DIYS speaker, if you are so lucky to have the room, but never use the plans from that time. Go active from the start and build some kit with a reputation. You will have an incredible result from todays material at very fair prices. Hunting for vintage drivers is a different hobby, not about absolute quality. You can compare it to collecting Edison wax recordings...
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Hard to get your hands one, and as i understand itm not stable but on ancient MathCAD (?).
dave
Hard to get your hands one, and as i understand, not stable but on ancient MathCAD (?).
HornResp is what we mostly see, SpcitTL is interetssing, and someone should take this one and finish it — https://www.diyaudio.com/community/threads/transmission-line-modelling-software.220421/
dave
I grew up in Lincoln, Nebraska and it’s almost certain that these kits were offered by a guy named Richard “Dale” Pitcher who later had a company called Essence Speakers which made transmission line speakers using typically Morel and Dynaudio drivers.
Essence Speakers was in the 80s. For a little while he had a showroom at or near that M St. address. Before that, his products were sold through a local dealer called Sound Dimensions. I also sold my own brand of speakers through that same dealer for a short time. I was 17.
Essence speakers were very good looking; idiosyncratic; had meticulous detail; sounded very good with certain kinds of music, and had a very small and devoted cult following. They had a very lean disciplined sound that was light on bass.
I agree with others in this thread that you can build far better transmission lines with today’s knowledge than anything anybody was doing back in the 70s and 80s. I’ve built a lot of TLs myself.
The mathematical modeling of programs like HornResp takes TLs to a whole new level. I also agree with the comments about KEF drivers. Modern units from leading companies are much better.
Essence Speakers was in the 80s. For a little while he had a showroom at or near that M St. address. Before that, his products were sold through a local dealer called Sound Dimensions. I also sold my own brand of speakers through that same dealer for a short time. I was 17.
Essence speakers were very good looking; idiosyncratic; had meticulous detail; sounded very good with certain kinds of music, and had a very small and devoted cult following. They had a very lean disciplined sound that was light on bass.
I agree with others in this thread that you can build far better transmission lines with today’s knowledge than anything anybody was doing back in the 70s and 80s. I’ve built a lot of TLs myself.
The mathematical modeling of programs like HornResp takes TLs to a whole new level. I also agree with the comments about KEF drivers. Modern units from leading companies are much better.
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Actually a few years earlier, more 1975-1980. And no, MD elements were common, including the legendary Stanton EEE. After 1984 I mostly listened to CD.
True, I did not hear the large HiFi speakers like you did. And true, there was the British sound. But also the German sound (Magnat, outstanding brightness) and the American sound (too much bass, too much treble). That is how I experienced it at the time. Take that literally I am talking about experiences back then. After 1986 I hardly did any listening comparisons anymore.
Totally correct. I don't recall how the sound was, I recall the feeling and experience. I recall that the Roger's Monitor never disappointed on any music style. Neither did the State of the Art. The only thing was the SotA bass extended further in the low range.
I don't know. I am using modern equipment, but it seems I have much more challenges with room resonances and listening position than back then. That is no objective assessment of course. When I still had the Roger's, I recall I hardly experienced those problems. (Note the use of the words "recall" and "experience"). Besides my ears have seriously deteriorated and also my state of mind has matured for another 40 years.
The only thing which did not change is the music from the 1970-ies and 1980-ies which is still as good as it was back then(*). And much better compared to the post-2000 crap. I hope we can agree at least on that. 😀 😀
(*) I should add something here. The 1970-ies and 1980-ies music which had a high position in the charts. When I watch a full music program from that era like ZDF Hitparade, or the Dutch Toppop, it strikes me how much crap was produced and played which never ended up in a high chart position. Obviously, the music that stuck were the hits.
Nostalgia can be a very meaningful design concept. Technology has improved, but good enough is good enough when it comes to enjoying some music. There is nothing wrong, IMHO, with a little reuse and recycling in our hobby. Much like old bicycles, there are countless usable older audio designs and parts out there just waiting for a new home.
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Today we have excelent drivers on the DIYS market, compared to the 80's at ridiculous low prices. In contrast to audio branded parts for passive crossovers, that have not changed and are absolutely overpriced today and make constructions on a try and error base impossible. The good news is, active speaker building with a DSP and measuring systems are much cheaper now. You get a calibrated microphone for the price of a few "made for audio" capacitors. Look for REW, as a free program.
If you are on a budget, a DSP and two stereo D-amps are often cheaper than a passive 2-way crossover. Not to speak from better sound and endless options to tune the DSP. Which for the majority of DIYS enthusiasts sure is simpler than building a passive x-over .
When it comes to more exotic constructions like transmission lines and DIYS horns, simulations will show you how bad those of the time really have been. Horns usually worked quite well when designed by the large players, but any transmission line, as a uncommon principle, was miles away from the optimum. They only worked with complicated damping, hardly to reproduce and ruining most of the theoretical advantages.
Also todays drivers have much more excursion, enabeling very different constructions, which is accompanied by powerfull amps for prices unthinkable at that time.
If you want to build a transmission line, even if you are new to it, maybe do an own construction, based on a free simulation program. http://www.hornresp.net/ will be all you need. You may keep the proportion of a vintage construction, but do it right inside. Even simpler, build a newer construction, based on simulation, documented and measured. Just search a little. For most people the transmission line of today is the tapped horn, the basic construction is hardly much different.
If you are on a budget, a DSP and two stereo D-amps are often cheaper than a passive 2-way crossover. Not to speak from better sound and endless options to tune the DSP. Which for the majority of DIYS enthusiasts sure is simpler than building a passive x-over .
When it comes to more exotic constructions like transmission lines and DIYS horns, simulations will show you how bad those of the time really have been. Horns usually worked quite well when designed by the large players, but any transmission line, as a uncommon principle, was miles away from the optimum. They only worked with complicated damping, hardly to reproduce and ruining most of the theoretical advantages.
Also todays drivers have much more excursion, enabeling very different constructions, which is accompanied by powerfull amps for prices unthinkable at that time.
If you want to build a transmission line, even if you are new to it, maybe do an own construction, based on a free simulation program. http://www.hornresp.net/ will be all you need. You may keep the proportion of a vintage construction, but do it right inside. Even simpler, build a newer construction, based on simulation, documented and measured. Just search a little. For most people the transmission line of today is the tapped horn, the basic construction is hardly much different.
The reason I made that caveat about DAC‘s, is that all active gain stages add a type of noise and distortion that passive crossovers do not add.
Decent passive crossover components are pretty benign in terms of distortion, and that is the one thing they have going for them. While all microphone preamps, preamplifiers, mixing boards, analog tone controls, etc. add a layer of film to the sound.
Digital to Analog converters are no exception, but one of the nice things about a digital crossover is that the signal can be kept digital all the way to the outputs of the crossover. And then your signal is as good as the one DAC in the chain.
The crossover can also serve as a digital tone control (with surgical precision as well) so if your crossover has a good DAC, you get more signal purity than any traditional $20,000 analog preamp can ever achieve.
Decent passive crossover components are pretty benign in terms of distortion, and that is the one thing they have going for them. While all microphone preamps, preamplifiers, mixing boards, analog tone controls, etc. add a layer of film to the sound.
Digital to Analog converters are no exception, but one of the nice things about a digital crossover is that the signal can be kept digital all the way to the outputs of the crossover. And then your signal is as good as the one DAC in the chain.
The crossover can also serve as a digital tone control (with surgical precision as well) so if your crossover has a good DAC, you get more signal purity than any traditional $20,000 analog preamp can ever achieve.
Giving nostalgia credit where credit is due… @BruceAllen I heard the KEF 101s when I was 13 and they made a huge impression on me. The salesman played a Supertramp album and I was astounded at the 3D imaging and clarity.
Of course the 101s are cousins of the LS3/5A. I have a theory that the LS3/5As have a "signature sound" that a lot of people in the audio biz acclimated to... and I think it has a lot to do with the Bextrene cone material. All the Bextrene woofers I've ever heard have a particular coloration that I describe as warm, romantic, buttery, "tube-like" and emotional. Euphonic.
That includes several of the other famous KEF speakers from the 1980s like the 103s and 105s as well as the Linn Isobariks and Linn Saras. I’ve written more about this in some other threads.
Bextrene sounds fantastic on certain kinds of music, especially jazz, vocals and choruses. (Precisely the sort of music that tends to sound good on low efficiency monitors that lack bass.)
For certain moods and kinds of music that’s the perfect speaker. Referencing comments by @Turbowatch2 above, a JBL is designed around a different set of priorities. I’ve made a lot of speakers much more in the JBL vibe (like the Bitches Brew Dipoles) which I think are much more accurate.
Yet there’s still something to be said for nostalgia and a few months ago I built a nostalgia system where the idea was to create a speaker of this particular genre. @Turbowatch2 calls it the “British sound”, I call it the “French sound.”
I bought a pair of Focal 5N402-DB woofers. They're from the mid 1980s. Though not Bextrene, the cones are soft black pliable plastic. They look almost exactly like the KEF B110s and they have fewer resonances. Very accurate, well engineered woofers. In the KEF tradition but next generation.
I paired them with an Audax TW025, which is nearly identical to the classic HD100D25 25mm dome tweeter, and they sounded exactly like I wanted them to: Extremely neutral with great imaging and clarity, but a just slightly warm romantic lower register that makes vocals really seductive.
The crossovers are passive and I discovered some new things about cabinet diffraction in the process which I wrote about here.
So yes, I absolutely identify with your affection for speakers of this particular vintage. Depending on how technical you want to get, you can buy classic drivers of whatever time period you prefer, and end up with a system that has the romantic qualities, while at the same time exceeds those old designs in many respects.
These 11 liter 2-ways I described have 6.5” passive radiators on the back tuned to 47Hz, and with no assistance have at least 1/2 octave more bass than the LS3/5A’s - maybe 2/3 octave more. I used the MiniDSP 2x4HD not as a crossover but as a digital EQ to boost the bass 6dB at 50Hz and sharply cut it off below that frequency (to reduce excursion below Fb). 6th order vented alignment, a "DSP Assisted Reflex" (see also here) which is very effective at boosting bass while reducing cone excursion and distortion.
So with some modest digital EQ they have robust bass down to 45Hz and play quite a bit louder than the KEF or Rogers ever did.
Of course the 101s are cousins of the LS3/5A. I have a theory that the LS3/5As have a "signature sound" that a lot of people in the audio biz acclimated to... and I think it has a lot to do with the Bextrene cone material. All the Bextrene woofers I've ever heard have a particular coloration that I describe as warm, romantic, buttery, "tube-like" and emotional. Euphonic.
That includes several of the other famous KEF speakers from the 1980s like the 103s and 105s as well as the Linn Isobariks and Linn Saras. I’ve written more about this in some other threads.
Bextrene sounds fantastic on certain kinds of music, especially jazz, vocals and choruses. (Precisely the sort of music that tends to sound good on low efficiency monitors that lack bass.)
For certain moods and kinds of music that’s the perfect speaker. Referencing comments by @Turbowatch2 above, a JBL is designed around a different set of priorities. I’ve made a lot of speakers much more in the JBL vibe (like the Bitches Brew Dipoles) which I think are much more accurate.
Yet there’s still something to be said for nostalgia and a few months ago I built a nostalgia system where the idea was to create a speaker of this particular genre. @Turbowatch2 calls it the “British sound”, I call it the “French sound.”
I bought a pair of Focal 5N402-DB woofers. They're from the mid 1980s. Though not Bextrene, the cones are soft black pliable plastic. They look almost exactly like the KEF B110s and they have fewer resonances. Very accurate, well engineered woofers. In the KEF tradition but next generation.
I paired them with an Audax TW025, which is nearly identical to the classic HD100D25 25mm dome tweeter, and they sounded exactly like I wanted them to: Extremely neutral with great imaging and clarity, but a just slightly warm romantic lower register that makes vocals really seductive.
The crossovers are passive and I discovered some new things about cabinet diffraction in the process which I wrote about here.
So yes, I absolutely identify with your affection for speakers of this particular vintage. Depending on how technical you want to get, you can buy classic drivers of whatever time period you prefer, and end up with a system that has the romantic qualities, while at the same time exceeds those old designs in many respects.
These 11 liter 2-ways I described have 6.5” passive radiators on the back tuned to 47Hz, and with no assistance have at least 1/2 octave more bass than the LS3/5A’s - maybe 2/3 octave more. I used the MiniDSP 2x4HD not as a crossover but as a digital EQ to boost the bass 6dB at 50Hz and sharply cut it off below that frequency (to reduce excursion below Fb). 6th order vented alignment, a "DSP Assisted Reflex" (see also here) which is very effective at boosting bass while reducing cone excursion and distortion.
So with some modest digital EQ they have robust bass down to 45Hz and play quite a bit louder than the KEF or Rogers ever did.
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I scrapped my 70s KEF TL decades ago and rather fancy building another pair in a similar style if the next house has the space. The Falcon drivers are expensive, provide modest performance at best by modern standards and there have been posts here about significant build quality issues although I don't know how widespread these may be. They obviously have value as replacement drivers for 50 year old speakers but for a new build they make little-to-no sense.
I have had a quick browse for current large floor standing 3 way transmission line DIY designs using a 12"(ish) woofer and not come up with much (given advances in tweeter peformance there is much less need these days for a 4 way compared to 50 years ago). Anyone?
Thanks for your sympathy. However I was 26 at the time and I couldn't wait to buy a CD player from my first earned money on my first job. And I can tell you it sounded darn good, missing out all the rumble, hiss, noise, static and crackles from vinyl records. In the past 40 years progressiveness slowly morphed into nostalgia.
@perrymarshall funny you mention the Audax TW025, today called TW25A0. For many years it was one of my favorite HIFI (and car audio) tweeter. It is still made and reasonable priced, too. With the right midwoofer it can reproduce even very aggressive guitar play and percussion at ear bleeding volume without missing details at lower levels. It was used as OEM in countless expensive speakers, often with a changed front plate design. It may not be the best tweeter on the market today, but still is better than many in its price class (39€). Surprisingly constant even after some decades.
The Focal you mentioned where used in many small two ways, as a mid driver I preferred the Podzus-Görlich of compareable size.
I never got warm with the LS3 and its clones. Today ridiculous expensive nostalgica, even as the got quite some improvements, so in fact may be much better than the original, hyped things. People that got them usually had small rooms, heard unpopular music and made a kind of secret science out of record players and amps to use. Any critical comment was erased with "you used the wrong xyz something" or some other excuse. May it be record player, pickup, amp, cable, feltpad or even speaker stand. Most of them later dreamed of a "Linn chain" of some kind.
The four way combination in some of these old constructions, often with a certain Celestion super tweeter, are a thing of the past. More a bug than a feature, they fixed the missing sparkle of the main tweeter used. Today a decend tweeter does 2.000-20,000Hz without any problems. No need to copy that.
Yes, the old transmission lines have fallen out of favor a bit,simply because they didn't work well. Today the principle is not clearly recognizeable at first sight, but still used, only with quite some modifications. There are many close relatives, like mass loaded TML or reflex resonators or the mentioned tapped horns. This is because simulations show us how it can be done better today. So if you are looking for the best sound characteristics you remember from an old TML, they are still there, only better and more refined.
If you can define what you are searching for, in size and performance, there should be some good plans around. I remeber quite some constructions in German publications. No need to use questionable expensive drivers, too.
The Focal you mentioned where used in many small two ways, as a mid driver I preferred the Podzus-Görlich of compareable size.
I never got warm with the LS3 and its clones. Today ridiculous expensive nostalgica, even as the got quite some improvements, so in fact may be much better than the original, hyped things. People that got them usually had small rooms, heard unpopular music and made a kind of secret science out of record players and amps to use. Any critical comment was erased with "you used the wrong xyz something" or some other excuse. May it be record player, pickup, amp, cable, feltpad or even speaker stand. Most of them later dreamed of a "Linn chain" of some kind.
The four way combination in some of these old constructions, often with a certain Celestion super tweeter, are a thing of the past. More a bug than a feature, they fixed the missing sparkle of the main tweeter used. Today a decend tweeter does 2.000-20,000Hz without any problems. No need to copy that.
Yes, the old transmission lines have fallen out of favor a bit,simply because they didn't work well. Today the principle is not clearly recognizeable at first sight, but still used, only with quite some modifications. There are many close relatives, like mass loaded TML or reflex resonators or the mentioned tapped horns. This is because simulations show us how it can be done better today. So if you are looking for the best sound characteristics you remember from an old TML, they are still there, only better and more refined.
If you can define what you are searching for, in size and performance, there should be some good plans around. I remeber quite some constructions in German publications. No need to use questionable expensive drivers, too.