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Folded ML TQWT for Radio Shack RS 40-1354a
After I had published the "Straight Pipe" ML TQWT, I got requests for a folded version. I drew these plans, which produce identical results to the straight version. I did, however, draw a circular port. This circular port and the original shelf port may be used interchangeably.
They are going away to college for dorm room use. They should be plenty for that.
The enclosures are built to your folded measurements. I used 1/2" obeechee plywood. There are 11 plys in that thickness. Instead of running the back all the way down I stopped it short and used the space to mount the compensation circuit. The slot uses the measurements from the tall version of the pipes. The front, divider, top and back all have 1/8" tile on them. There is about 3 oz of WalMart's best fiberfill from the bottom of the driver on back into the "top".
The mosaic outside is 1/4" thick ceramic tile. The stripe is 6" wide and there are two edge strips of pine, each about 1" wide. The paint is dupli-kolor Fleck Stone. It took about a can and a half to do the enclosures. Prepainting with grey paint helped but the fleckstone covers quite well on it's own.
As far as the speakers, I built them to your specifications in 3/4 MDF, clamped and glued. Each pipe has about 4 oz of Polyfill in the upper section around to just below the driver. The driver's aren't flush mounted. I wired the drivers with 18 gauge solid core copper wire from Radio Shack. I went with the tube port and 4" seemed to sound the best, though the differences seemed much more subtle then adjusting the length of a port in a BR enclosure. After listening to them for a while, I decided not to do the baffle step compensation, as they are currently up near the walls and imaging hasn't suffered much at all. I'm working on a pair of surrounds. I have yet to track down a fifth 1354 for a center channel, but after watching a few movies in just stereo, I don't really think I need one.
Jake Hartsoch
Missoula, MT
Folded ML for Fostex FE164/167E
This is a proposed design based on Martin King's MS TQWT. It is simply King's ML TQWT folded. The design is for the Fostex FE164, which is now out of production. The closest replacement, the FE167E should be a drop-in substitute. The FE167E is shielded, but the parameters match the FE164 more closely than the unshielded FE166E.
The modeled output is:
I am using $1.99 Radio Shack binding posts and 1 strand of 24 AWG pure silver wire internally to the driver.
The sound is very solid and punchy. The treble is rolled off pretty badly with all vocals sounding like the singer has a head cold. I think that will resolve itself with more break-in and experimentation with stuffing.
My plan is to let them break-in for a few weeks (or as long as my wife will let me leave them rough) and then seal and stain them. These speakers are keepers.
This design was done for a gentleman who e-mailed me for a suggestion for the FE168S. It needed to be reasonably compact -- for a smallish room. As I continue to refine my thoughts about quarter-wave pipes, I am now thinking of straight TL's, but with fairly small ports. The drawing is a quick pass at a basic square box, but the dimensions are good. I don't think a square cross-section is a problem, since the box is heavily stuffed. The design goal was f3=40hz.
The modeled output:
And the drawing:
