The Good Wife, and I have decided to, tentatively, throw out the tube amp and Magnepan speakers from the living room, and build a monster sound bar for the TV. The idea, has been in the back of my head since the experimental Boom Bench several years ago, out of two folded quarter wave horn speakers with Tang Band 4 inch full range speakers. This time the project is inspired by a more woodsy interior refurbishment, and my love of the 8 inch Visaton B200‘s that reside in the man-cave.
I found a pair of lightly used Wild Burro Betsy-K speakers, with Planet 10 Phase plugs for sale on Finn.no They will form the basis for the build. Now, instead of doing all the calculations and correctly sizing the cabinets, I am going to go the carefree and careless approach of designing something that fits under the TV and seeing what the sound is. Afterwards I will try to amend any issues by ear, with stuffing, baffles, notch filters and similar. Imaging will be bad, bass response is not expected to shake the house. but for uncritical family listening, and a little bit more omph to movies, I think my cohabitants will be pleased. So without further a-do, here is the design:
Dimensions are 110cm long by 25cm high by 40 cm deep. What will be inside this box, you ask, TAO?
A chip-amp, possibly with Bluetooth for family members smartphones. Maybe some kind of ported, stuffed, single volume. The volume will not be large enough to make two individual back loaded speaker cabinets in one, I think. Bass will be strengthened by the placement close to the floor, and somewhat in a corner. As far as I have read Betsy’s are a bit bright, and many posters on forums compensate by playing them of axis. So maybe the low position will help a bit in that department. The proof of the pudding is in the listening. But first, shopping and chopping 🙂
Update January 13.
The cabinet is glued up and waiting for finishing .
22mm birch plywood, front and sides while the back is 8mm because that is what we had left over. I know, it’s too thin and will resonate. So what? I can knock them out and fit something substantial if its bad. I decided to divide the cabinet for left and right sides and make two bass slots in the back. The space between the slots will provide room for collecting cables from the TV so the floor is clean.
The chip amp, although recommend on DIY audio, did not sound good enough, and was set aside. For now I will power it with my Music Angel KT88 tube amp.
Update 28 February (Things Take Time)
I made tiny little oak legs! They are 85mm long 42mm square at the top and taper on two sides to 30mm square at the bottom. The dimensions where chosen to get a vacuum cleaner under and not lift the TV too high, oh and because that was what I got out of the block of oak I found.
I am mounting banana plug sockets on the back and test fitting the Betsys. The speakers are mounted from the rear in rebated holes that are routed to a 45 degree angle on the front.
First listen was much better than I had feared. It actually sounds good! There is decent bass when tested with Bela Fleck’s “Flight of the Cosmic Hippo”, and great vocal rendition on Youn Sun Nahs “Same Girl” album expected from the speakers. On some rock tracks by Brant Bjork there are some annoying medium high frequency tones. I will have to measure to identify the frequencies. Also a boxy sound. but that is to be expected since I am used to open-backed dipole speakers.
Update April 7
The speaker has been finished now for a while. I rubbed it with a white gloss paint on the sides, and wiped of the excess so the wood shows through. The front is left untreated for aging to take place. Just some final stuffing to do as I continue to listen to it. I have not added any notch filter so far. It mostly behaves well, only some tracks have an annoying frequency. (might be the track not the speaker.
If you want to build your own, drop me a note and I will give you the detailed dimensions.