Tuned pipes TL loudspeakers

[abn1701]

Hi!
What is a tuned pipe transmission line loudspeaker?
Is a tapered voight pipe like David Weems pipes?
A vintage High Fidelity Loudspeaker the Soliloquy mod. 5.2
was a tuned pipe TL and I'm curious about the internal configuration.
TIA

[Dirk]

I would have to guess that it's another name for a Mass-Loaded Transmission Line. The MLTL is basically an oversized ported box with an extremely low box tuning. This makes for a dip in response before Fb. The height of the box is carefully selected so that the quarter-wave resonance fills in the dip. You end up with F3s easily a half-octave lower than they'd otherwise be. Power handling goes out the window, though...

Having looked at images of the Soliloquy 5.2, that certainly looks like a port configuration that one might see in an MLTL. Another notable example of the configuration is the Salk SongTower (the port is on the back).