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...


Showing 5 responses by lrsky

You lost me, I had to reread my post...your talking about Jim Thiel's comments, right?
He's not the only person to take exception to the efficacy of the TL in loudspeakers, as I understand it. (One reason for the post actually).
Reading a bit, I hear things such as, "Since a bass wave that we're talking about is longer than the line itself, how can this work...." being one of the more popular nay sayer comments.
Then, I read again, as it's been years since I did so with enough interest to remember such...that the wool, (that Bud Fried used) and I prefer for sound dampening in speakers, causes the speed of the bass to change internally to approxiamately (too many factors to be specific), 85% of it's original speed, and that depending on the methods used, the bass tone is 'tricked' (not my words) into thinking the line is actually longer than it is, by an amount of distance which is significant.
Now you see why I posed the question.
I'm about to use a TL in a simple form, and compare it to just ported bass, in a bookshelf--and I'll be happy to pass on my subjective impressions of the quality of bass. (May take a little while).
So, I'd like to hear more of your opinions about the qualitative, (subjective of course)differences.
I do remember my IMF's having some of the most 'musical' bass I'd ever heard...especially given the cabinet size of the speaker I was listening to.

You've stated the very thing that makes this whole debate an ongoing one...
Just wondering, as a 50Hz tone is 25', how would that be possible? (To build a T Line as long as a bass wave). A 25Hz 50'...and so on. This is what Jim Thiel was referring to--whether valid or not, with regard to our ability to build such a device. (I refuse to discuss most theory, as people ususally know, myself included, just enough to argue not convince). What is everyone else missing?
Its tough for most people to separate what sounds correct, from what sounds like the thing that they're most used to hearing.
While designing, a tragic error can be to use a previous model, OR another speaker as a reference--don't get me wrong, it's almost impossible not to. However, as Michael Keaton said in Multiplicity, 'a copy of a copy of a copy is just not rignt.' Therin lies the danger. I had to, since I didn't happen to have a live band here, use a speaker, and I used the Sound Lab A-1--and its no surprise that my loudspeakers sound was natural, flat, while still musical, as the Sound Labs sort of set the bar in those areas.
However at some point you have to, in your mind's eye, still be able to hear/know what that bass being bowed or plucked, really sounds like, and have a really good sonic memory. All this is my way of asking, 'Does it sound like music, or what you're used to hearing from speakers'...and THAT is a distinction with a difference to me.
Then there's the 'Transmission Line Bass' has its unique sound,' camp. I agree, and I like that sound, and think that in some ways its more natural sounding.
The funny part about bass is that, bass gets its character from the midrange--2,3,4,5 and more octaves above the dominant tone that's expressed by the instrument.
When a double bass's open E string is plucked and 41.6Hz is put out there, it's really 83. whaever, then 166.whatever Hz and 332.Hz then 664Hz thats giving it so much of its tonality. Bass is curiously, or maybe not curiously the most complex aspect of music--partly because it's centered in our human hearing curves center--kind of.
Whatever, just rambling now.
More thoughts...your input(s) have been great!

You do know I wasn't saying that emperically, you didn't reference live music, right? It's just that very few people really have that inner reference, and sonic memory. I liken it to perfect pitch, or relative pitch...rare and unusual talent. I'm fortunate, in that I can hear, and remember...your comments are far from being unusual, hence the question. Its not a 'mild' complaint, almost a 'love it or hate it', kind of thing, so far, and you expressed a very valid, "I don't like it", which should probably should be, "I don't like WHAT I've heard SO FAR." I personally LOVED it, and was a little disappointed in the electronic sound of the equalized THIEL 03as that replaced my beloved IMF's, back in the day. I became accustomed to it, sort of like having a wife who smokes--you learn to look past it, I suppose. Older now, I have a smaller window of 'looking past', and want to really do it right.
My LSA's have good bass, and with the mosterous Air Core's that we used, and great caps, very tuneful. But, I want to move to the 'next and better thing'.
I'll tell you what's how 'right' the bass on the A-1 Sound Labs was--no cabinet noises, obviously, perfect phase, perfect time alignment--and it just sounded right. Maybe I want an electrostatic with that kind of bass response...I DID love it. They are so damn underrated in EVERY WAY!

See, your comments are very 'spot on' as to what I experienced. See Dodge, another, like it to offset. This is what's maddening.