Transmission Line Speakers

sprague lake, estes park, colorado, 09.19.2004

Transmission Line Speakers I've seen a couple of speakers on Woodnet and thought it would be cool to build a pair. I talked about it with my cousin Craig who knows a lot more about audio components than I do. He did quite a bit of research and really liked the design of the Triune TL from Curt's Speaker Building Site. We got all the audio parts from Parts Express. It cost around $120 for the speaker parts and another $20 for one sheet of MDF. For $140 I have some great sounding speakers that were fun to build. Thanks to John Fry for his email help with my shop-sawn veneer questions. You really need to check out his website to see some incredible custom-crafted furniture.
The speaker cabinets are made out of MDF. Here is Craig getting his first taste of MDF dust!
The pieces needed for the speakers are pretty straightforward.
1/2 inch rabbets in MDF creates a ton of dust.
Pocket screws made the assembly of the cabinets go quickly.
Here are the cabinets finished with one side removed. We didn't want to glue the second side until we made sure everything was working.
I had some curly maple veneer but it was 1/2 inch too narrow to use on this project. I thought about buying some other veneer, but decided to try resawing my own rift-sawn red oak. I thought the board in the middle might have a little figure so I used it for the sides.
Here is the veneer I cut for the sides. Here is where having an 8" jointer would have been really nice. It took some patience, but I managed.
We screwed the sides on and gave them a listen. We were both very impressed with the sound. I couldn't believe the quality of the bass the 5.25" woofers produced. Susie just loved the MDF with primer look - NOT!
Craig built the crossovers.
After listening to them for six weeks, it was time to finish them. I removed the unglued sides and here is what the insides look like. It looks like there's a ton of filament stuffing in them, but it's just really fluffy.
I used semi-flat black spray paint for the backs.
Gluing the veneer to the cabinets took some thought. I think I ended up getting a good bond to the MDF.
I used Varathane Golden Oak stain. I wiped it on with a rag and wiped it off after a couple of minutes.
I put several coats of Waterlox Original Sealer/Finish over the stain. I was extremely happy with the results. I put the speakers back in and tested them out.
This picture shows the figure of the rift-sawn red oak I used on the sides.
One more picture from a higher angle.