Transmission line speakers!

Fried made a lot of models back in the day.

https://hifihaven.org/index.php?threads/fried-transmission-line-satellite-and-subwoofer-design.3638/page-2

I also had a pair of Fried transmission-line speakers. Can't remember which model, but if I recall, they has some kind of cross-connectivity like Polk SDA. I could be wrong about that. I didn't have them for very long, and it was probably about 20 years ago.

• https://www.usaudiomart.com/details/649184875-tdl-monitor-m-transmission-line-speakersl/images/929958/
  These are the ones that I had with the B110 elliptical bass driver and super tweeter. It was a large speaker, but very good for the time, and the bass was not, but it was able to reach below 20hz.
• The pair in the picture were not mine. Mine had a naked Elac metal dome tweeter and what the brochure called a "mineral" supertweeter.

None of them were. 

Infinity made the claim, not me. Oh, I guess I did...but I was referring to the Infinity's claim. I know they aren't a true labyrinth design but they stuffed the cabinet with absorbent material and lowered the port resonance. Maybe it was just fancy sales writers but they made the claim.  

My Infinity Monitor IIa’s are transmission line.

One of my favorites, only to be replaced by my Reference Standard 2.5s which I kept for many years.