I designed and built (still under construction actually) a center channel transmission line. This one is quite unique, and I don't know exactly how it will perform. I have some concern that there might be some big dips or peaks in the lower frequency range due to the two into one design. It is tuned to 64 Hz, which should provide adequate low end response since it is only a center channel... that and I was limited on how long I could make the chambers. The speaker will nestle right under my old 27" tube TV (the projector screen pulls down in front of the TV). I am using two 6 1/2" woofers, and one 1" fabric tweeter. I will post more pictures and comments as this project progresses.

Here is a top view before sealing it up. It was very difficult to get everything to line up properly. Being short 1/16th of an inch is like trying to span the Grand Canyon when it comes to speaker cabinet making. Thank goodness for liquid nails!

I like it. It's kind of a shame about all the little dead space areas, though. My brain wants to find uses for small triangular shaped pockets...

Places to hide spare remotes?

I built the crossover last night (2-way Linkwitz-Riley), wired the box (which turned out to be somewhat tricky since the box was sealed up and my arm isn't triple jointed), and fit both woofers and the tweeter in place. I ran some test tones and it sounds pretty good. It extends much deeper than I thought it would (~40Hz), of course I haven't stuffed it yet so that may decrease the bass extension by a few Hz. There are a few peaks and nulls that will be addressed with stuffing; but I really need an anechoic chamber to tune this thing since my main listening room has a huge cancellation at about 80Hz (verified with many other speakers).

I still need to do final sanding on the enclosure before finishing it. I am quite impressed on the bass extension of this speaker, much better than I had anticipated. It is quite big and heavy, but it will fit nicely under my 27" tube TV. More pictures to follow soon....

I finally got around to my 3D model. I am currently in the process of painting the center channel so I had some time to finish the model...

Here are two pics of it "done". I am still fussing with the stuffing density, and I am going to rewire it as well, but I wanted to use it while I still fuss.

Stay tuned for a set of main speakers using the same drivers as this but using a much longer/larger TL enclosure for better low end...

thats a nice looking speaker you got there !

does the size of the tweeter affect the output from the woofers ? i ask because when T/L speakers are under ported it tends to
do funny things to the way they sound, ie muddy and closed.

Another thing you may want to do, is sand fill all the triangle cavities you have and round of the corners on the protruding panels.
Or has it all been sealed up already ? if so, completely forget what i've just said !