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Transmission Line Bass

As a long time proponent of good bass without subs, I like tinkering with different ways of approching the age old problem of recreating all energy below 100Hz.
Seriously, if you look at loudspeaker responses, everything seems goes to hell just below that point, swinging wildly in output response, almost independent of many of the typical factors that would be indicators of performance.
So, the question.
Who among us has had extensive Transmission Line Bass Experience in listening, (like me with the IMF's in days gone by, with Bud Fried being a wonderful mentor to me).
In Jim Thiel's lab, one time he told me 'candidly' that Transmission Line Designs 'in theory' don't work. (Another discussion for another time). But he, like me was a bass freak of the first order, loving a rich full bottom end, hence some of his equalized designs early on. They were an all out attempt to bend the laws of physics.
So, what do we think of Transmission Line bass--so, if you're familiar with the sonics though actual listening, and can express first hand opinions let us hear your impressions of the differences between ported, passive radiators and transmission.

Thanks in advance...

Larry
lrsky
lrsky OP
1,118 posts
 
Csmgolf,
See, your comments are very 'spot on' as to what I experienced. See Dodge, another, like it to offset. This is what's maddening.

Larry
listener57
730 posts
 
I enjoy listening to
Clements RT-7
with its version of transmission line bass and ribbon tweeter.
Sounds very satisfying over a few decades.
Positively thrilling on good recordings of music from challenging opera and organ right on down down to solo vocalist, piano or violin.
I also go to a lot of live performances.
A home system properly reproducing a great recording is not usually able to reproduce what I actually hear (or, heard) in the audience at live performance. Still, we all can know and enjoy great sound when we hear it in the home setting.
Hearing pitch accurate, musical TL bass that subjectively "keeps up" with a ribbon tweeter is a speaker designer feat, for sure.
Congratulations to Philip R. Clements. He is worthy of mention in the same breath with other elite speaker designers.
coffeey's avatar
coffeey
363 posts
 
Clements 207 D I's and a pair of 107 D I's outstanding clean bass.
sounds_real_audio
958 posts
 
I think that the most important improvement in the bass when using a Transmission Line is not so much the depth of the bass but the quality.. I attribute that to the face that the rear waves off the back of the driver is not just absorbed by the MDF (in most speakers) but rather has an outlet. This must reduce the resonance considerably. I remember when I built the Fried's using Bud's 12" driver I asked him if it would be better to use MDF the the plywood in his plans, (they were do it yourself) speakers. He told me that he didn't feel any resonance in his cabinets that were made from plywood.

Of course I ignored him, who wouldn't, he was just an old man, and I was young and much smarter then he was... then the wisdom of his choice came to light when I had to carry the speakers up stairs from my shop in the basement.

Larry lets us know how your experiment goes.

Jim
Sounds Real Audio
ngjockey
1,042 posts
 
Can you spot the problem with transmission lines...?

http://www.rwgiangiulio.com/math/pipelength.htm

The advantage is managing the phase from the back wave to reinforce or null at specific frequencies.

Traditionally, a transmission line is tapered and "stuffed" which absorbs some energy, lowers Q, and reduces bass extension. Been playing around with another idea that takes advantage of the difference between slow air movement and fast sound travel but, as yet, untested. Expect complications.
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