Differences Between Folded Horn Speakers and Transmission Line Speakers

@larryi Thanks. I could kind of see it, but I wasn't sure if it was just the one folded horn I had seen or it it was generally the case. I definitely didn't know the reason for the shape of the folded horn.

Additionally, how would you compare the sound of the folder horn verses the transmission line speakers? I haven't heard the TL myself, but I understand that they are very good at producing the lower frequency range. Like I said, I know nothing about folded horn or how they sound.

Thanks.

The transmission line speakers I heard had very tight bass and sounded quite good.  They were also reasonably compact and did not require a lot of depth.  The various folded horns, like the Tannoy speakers, sound really good, although the bass did not go extremely deep in frequency, and most were quite lively sounding.  In recent years, I’ve heard single- driver backloaded horns systems, like those from Charney Audio, that blew me away because they sounded so lively, rich, and smooth—so much more complete and free from peakiness than most other single driver systems.  The Charney speakers were compact in width and height, but were quite deep to allow for the back horn.  A big plus with backloaded horns is that the high efficiency allows for use of low-powered tube amps thst are my favorite amps.

Sounds nice. I might have to try a pair; one of each type. Thanks for the info. 

I may not be entirely correct here, but I think of folded horns as horns and TL as competitors to the ported enclosure.  That is, horns gain efficiency through the improved impedance match of the driver to the air via the horn.

The TL however AFAIK has similar efficiencies in the high frequencies of a sealed or ported speaker, it’s the deeper and more extended bass that make them worthwhile. 

I'm sure others will correct me.

With horn compression drivers, typically used for midrange and high frequency drivers, air is confined in a chamber and this does effectively increase impedance to allow for a better coupling of the driver to the air.  This certainly does improve efficiency greatly.  With woofers with a back-loaded horn, there may be some such impedance improvement, but, the biggest improvement comes from not trying to dissipate this back wave, rather, to lengthen its path so that the backwave, which starts out inverted in phase with the front wave, is now in phase and augments the front going wave.  Transmission lines are more in the business of dissipating the back wave energy at higher frequencies through use of damping material lining the tunnel.