Transmission line speakers!

I had  pair of Spendor D7 which uses a quasi-transmission line bottom firing port.  The bass and sub-bass was so deep and effortless, a speaker with very special bass.  It improves the efficiency of bass response and makes them easier to position. 

My issue with the Spendors is that they were voiced nearly flat without the usual midbass bump.  Otherwise they would have been perfect. 

T-line designs have the potential to be outstanding.  Application is unfortunately not consistent. 

bkeske,

I'm not sure of how a transmission line port differs from any other port, but that is only part of what a transmission line is. It should include a long folded labyrinth from that rear of the bass driver to the port. I would like to hear from others more knowledgeable than myself here as to whether they consider this a transmission line.

I think PWK’s folded horn was an extension of the principal.

I think it is the opposite, the transmission line is using a quasi folded horn principal with a port. Whereas a true folded horn will exit the air in the woofer chamber out the mouth of the horn (no port). I could be wrong...

Mike

...I used to have a pair of those WTLC's...long ago, far away...

Ask me about the time we hooked up four Infinity Column IIs, and connected to a Phase Linear 700, in Pacific Stereo's big room. Even with the doors closed and way in the back of the store. They asked us to turn it down because they couldn't hear customers at the front of the store. I bought a quad for myself.   

@roxy54

bkeske,

I’m not sure of how a transmission line port differs from any other port, but that is only part of what a transmission line is

And logically, it would be hard to have a transmission line port without a transmission line behind it.

I grant you, I’ve never seen a good clear cut-thru image of the ‘transmission line’ to show what your rightly question, but Richard does use that verbiage when describing the bass design of the 1’s. And that lower cabinet does exist below the 8” driver. Is Richard misusing the term? Possible, but he is a pretty smart guy, so there must be a reason he has and is still using the term. Perhaps you could contact Richard directly, I’m sure he would respond.

Or, perhaps @tomic601 could clarify as he has had wide ranging discussions with Richard over the years, and this may have been one.