Who makes a "true" Transmission Line speaker?...

There are many different types of designs that fall under the category of "transmission line". Some offer a consistent size "tunnel" from start to finish, some are tapered, some are flared, front or rear loaded, etc... Each has their own benefits / drawbacks. I think that "Audio" magazine had a pretty decent article about the variations that one could encounter on these designs, but that was probably at least 25 years ago or so.

While i don't know if they are still around, Kinetic Audio used to use a TATL ( Tapered Acoustic Transmission Line ) design. Some brands, like Von Schweikert and DCM, who claim to have TL designs, are not anywhere near what one would consider to be a "true" TL.

Audio Xpress ran an article on a "DIY" speaker project that utilized TL back-loading of the woofer. Several graphs and charts demonstrating how hard it was to properly fine-tune and the amount of reflections / standing waves / non-linear output that one encounters using this approach. One of the hardest to build & design correctly, hence the lack of information and commecial offerings.

Old Colony Sound Labs just released a computer program that allows for various TL designs to be simulated, so those that are truly interested in DIY'ing a set of TL's might want to check into this. Sean
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Kehut, I think they were the X-929. They were a tall, slim, high gloss black and maple (REALLLLLLLLLLY beautiful) speaker, using a D'Appolito arrangement. Not the deepest, punchiest, most resolving, or fastest speaker I have ever heard, but extremely easy to listen to. I would say that as my first encounter with the company, I was more than impressed. In my opinion, they were much superior to the Von Schweikert VR4Jr speakers that were next to them. Most in our group also strongly agreed.

Peter_s, if you liked the Frieds at CES2004, you will really love the current speakers. They are at least two steps up on the scale. The new ones are better in each and every way - more attractive proportions and incredible veneer, much better drivers (Vifa - low Qts, instead of Peerless), correct line damping, better crossovers (with correct values). Let's just say that what you heard was an early prototype, the current product getting released as we speak is just a speaker that one can take to market. How this translates sonically is night and day better imaging (you will be amazed that a big three way can do this), a lot more speed, clarity, resolution, deeper bass, more easy to listen to (the others were harsh), and the superior attack and decay of the notes from the low Q drivers and good line damping is something of note.

Buggtussel is out of business. FWIW, I have had the Amygdala's in my house, as Bugtussel was located near me, and while the Amyg's were fun on some rock music I wasn't overall taken with them. IMO, you can do better.

Jean-Marie Reynaud makes TL speakers.

Yes Kinetic is still around. I've had a pair of Labyrinths
since 1996 and I can't imagine ever getting another pair of
speakers. Production is very limited now however. I think
Ted Karson owner/designer is looking towards retirement.
Ted manufactures all of his own drivers. He makes some of
the best 12" woofers on the planet and sells them raw if you
like DIY projects. He's a big fan of Bud Fried dating back
to his original IMF designs.

As far as his speakers are concerned, his larger designs are
what this thread is calling "true TLs." My Labs have a 12"
woofer loaded at the end of a 1.2:1 ratio tapered line
that's 10' long. The terminus is 10" and located near the
top of the rear panel. They're 52" tall and weigh 250lbs
each. F3 is given as 16Hz. I have mine vertically biamped
with a pair of ARC D400mkIIs and I can shake the foundation
if I turn up the volume.

His smaller designs are quasi-TLs with tuned pipe approach.
He prefers simple 1st order crossovers although diverges
from Bud here in that he sticks with parallel crossovers.
He uses L-pads for driver attenuation instead of fixed
value resitors. Common back in the 70s but seems to have
fallen out of favor.

Anyway, check out the web page www.kineticaudio.com. The
pics of the Labyrinths are actually my speakers. I had them
veneered with real pre-quarantine Brazilian rosewood. He had
a small amount left in stock which dates back to the late
70s. It wasn't cheap but man it's gorgeous. Hence the pics.

If you want more in the way of TL design theory, check out
the sites www.t-linespeakers.org and www.quarter-wave.com.

As a side note, some of you may find it interesting to know that there is one bass cabinet manufacturer that makes transmission line cabs (almost exclusively) - Euphonic Audio. I have a number of their bass cabs, and not only are they deep, tight, and very uncolored (for a bass cab, mind you), but they also sound great for PA use. Their older, VL-series cabs are their best, IMHO. If this is of any interest, check out www.euphonicaudio.com.

Their lead designer, John Dong, started out in the high end audio speaker manufacturing business.