Transmission line speakers!

This is a great post. I learned so much about this and similar designs today that provide direction of my next speaker upgrade. Thanks for bringing TL design to the forum and thanks to all those that contributed to the discussion.

My current speaker set uses a loose concept of the TL design but I was unaware of how the construction is classified and incorrectly thought I had stumbled across a unique design. I am enamored with this low frequency sound and today have found the path to take when upgrading. Thanks again!

Irving M (Bud) Fried of IMF and Fried became a good friend of mine, and I was one of the owners of Fried Products.  He graciously gifted me his own personal loudspeakers shortly before his passing.  Bud famously championed the transmission line loading.  No one came close to evangelizing the advantages of the alignment.

What few realize is as terrific as TL is in the bass, it's even better in the midrange, as the notes simply fly out of the speakers.

Recently finished a new pair of TL subwoofers for myself to replace Bud's.  Their lovely cosmetics fit right into my living room, play cleanly and powerfully into the teens, and cost me so little most in this day and age dismiss them immediately out of hand.  More than that, the quality of the low frequencies they produce leaves me happy like few, if any I've encountered when it comes to musicality.  They simply sound more like real music, and astonish people with their sound and modest dimensions. 

I knew Bud and spoke with him several times when he was still running Fried. He was a real gent, full of knowledge and eager to share it. I owned one of his large bookshelf speakers, a transmission line design, and I remember well that he was one of the very first to design a sattelite/subwoofer system, (Model J?) and it was really impressive.

@roxy54: Are you thinking of the FMI (Fulton Musical Industries) Model J loudspeaker? It was comprised of three separate boxes: on the bottom a transmisionline-loaded woofer enclosure, in the middle a small sealed enclosure with an 8" woofer and dome tweeter (marketed separately as the Model 80), and on top an RTR ESL tweeter array (6 ESL tweeters per side iirc)---the same tweeter Dave Wilson used in his original WAMM loudspeaker. I bought a pair of the Model J in 1974, when it was priced at $1200/pr. JGH loved it, putting the Model J at the top of his recommended component list.

Before ESS introduced the Heil AMT loudspeaker, their flagship model was the TranStatic I, which was also a three way: a KEF B139 woofer in a transmissionline enclosure, a KEF B110 5" cone midrange, and three of the RTR ESL tweeters mentioned above. It retailed in the early-70’s for $599/each, and was competition for the Infinity Servo-Static I. I have a pair sitting in my spare room.

bdp24,

Hi, I might be giving it the wrong letter, but it was definitely Fried. They were the first mini monitors I had ever seen, and they were really mini! A small two way, amd an rectangular subwoofer that was fairly large. I saw it demoed at House of Hi Fi in Trenton NJ around 1976, when I was considering my first pair of speakers. It sounded really good, but I was 19, and nothing was going to keep me from buying either Bozak Concert Grands (which they also carried) or Klipschorns, which their competitor Hal's Hi Fi carried. The Khorns won.