Transmission line loudspeakers

December 31, 2022
 by Paul McGowan

20 comments on “Transmission line loudspeakers”

  1. I have TDL Studio 1’s in my man cave. Late at night when my wife has gone to bed I can listen to the music at low level and still feel the bass, not just hear it, feel it. This is a rare commodity in any speaker, even the Tannoy DC3000’s in the living room loose some of their clout below a certain level.
    For me the TL approach when done well is most persuasive.

  2. Aah, what a memory jogger for the last day 0f 2022! I lived in Philadelphia in the 1970s and my second speakers after my classic Acoustic Research AR2a’s(updated to AR 2ax’s) were IMF Studio MK2 transmission lines. IMF stood for Irving M. Fried(Bud Fried) and Bud lived in Philadelphia and I got to know him and we became good friends. I always recall the evening I ended up at dinner with Bud and Gordon Holt and David Hafler and Percy Wilson(the technical editor of Gramaphone magazine and a true horn expert) and their wives, probably the best hi fi evening of my life.

    What probably helped limit the growth of transmission lines(and basically killed acoustic suspension boxes, the dominant bass loading of the 1960s) was the Thiel/Small work that allowed scientific design of ported boxes rather than trial and error before that. The extra efficiency and increased sense of bass from a proper ported design was hard to resist especally since a port was a very inexpensive addition to a box.

  3. The advantage of TML speakers are that the woofer has not to work backwards against the air compression force of a closed sealed box. Result is less distortion and less heating of the woofer moving coil. For me it is the best way beside horn speakers. But true, the manufacturing is more complicated and costly. So not many loudspeaker companies do produce them. My TML speakers give a very good strong contoured bass with easy driving. No need for a 600 Watt amplifier.

  4. I had a car with a Bose (bozo) factory-installed sound system. It had a transmission line subwoofer in the back. A bunch of folded plastic tubes. It was an awful setup, and made the rear deck nearly unusable – it fit a briefcase.

    It sounded gross.

    So again, the implementation is key.

    1. JW,
      I had a pair of ALPINE – ‘Bass Engines’ screwed into the metal sub-chassis of my car’s front seats…WOW…talk about electric, ‘feelable’ bass…OH MY…right up my spine, no ‘doof-doof-doof’ upsetting the neighbourhood & all of my rear deck & boot space available.
      Magnificent invention 😀

      1. ‘Tactile Transducers’, great substitute for the audiophile who wants to feel the bass in their automoblie but doesn’t want a subwoofer box taking up space. Highly recommended, been using em since early 00’s.

  5. I built a pair of TLs back almost three decades ago. It was Lynn Olson’s Ariel design, a D’Appolito set up with two 5-1/4″ Vifas and a Scan Speak tweet. They were a labyrinth line, and the boxes were a b!tc$ to build. I still have them in my second set-up. They do have a certain magic at lower volumes by maintaining the dynamics better than most. As Paul said, there are now cheaper and better ways of getting good in phase bass extension.

    Happy New Year everyone, and much happy listening in 2023!



    1. As did I – probably closer to 40 years ago. Somewhere along the line during one of our several overseas excursions they were “disposed off” – much to my chagrin. I hope someone somewhere is continuing to enjoy them.

  6. I have been using a transmission line speaker for many years. I don’t know of any speaker that reproduces very quiet music with such an impressive bass. Transmissionline is an excellent speaker concept. I would agree with Sean O Donnell says.

  7. Ok, back in the late 80’s I built a dual transmission line for a 24 inch Hartley speaker to use as a subwoofer for my MagiTypani 3a’s to suplement bass OMG, never had bass like that in any other system I’ve owned

    1. That reminds me of a trip I made to Paul Heath Audio in Chicago, about that same time or maybe a little earlier, where they were trying out a turntable isolation device by placing it and the ‘table on top of a 24″ Hartley sub and cranking up the volume. The rest of the system (all of which sounded amazing, by the way) was Audio Research electronics and Tympanis.

  8. I lived very happily with a pair of transmission line speakers for many years – Meadowlark Audio Kestrel 2s (which I still own, but which have been set aside after returning to the Magnepan fold in 2019). I don’t think I realized they were transmission lines, though, until I saw a photo of the designer, Pat McGinty, holding up one that had been sawn in half, displaying the labyrinthine path created by a multitude of internal baffles.

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