Turning TriTrix: A Speaker Build Log
In late 2009, I realized something: I was unhappy with the Home Theatre in a Box (HTIB) system that I had hooked to my TV and Playstation. While I'm not an audiophile by any means (that is my wife's forte--I'm the wordsmith), even I could tell that the sound was tinny, empty, and bland.
The problem was, speakers are expensive, and there are a LOT of crappy ones on the market. Research on sites such as Hardwarecanucks.com and avsforums.com led me to believe that, with the right skills and patience, high quality speakers could be made for significantly less than the cost of a retail package--in fact, most people suggested that a DIY speaker, done properly, was worth a commercial pair at double the price.
Having a bit of a background in basic carpentry, I bit the bullet and purchased a TriTrix Recession Destroyer Kit from PartExpress.com The kit included all the materials needed to put together a pair of Mid-Treble-Mid (MTM) speakers, and there was a handy link to designs for the crossover needed to drive the speakers, and the enclosures they required.
I began, fittingly, with materials and tools. I bought myself my first table saw (pulled from a much more easily justified to my wife "tool budget"), borrowed a router from a buddy, and bought a 4x8 sheet of MDF.
The first big hurdle was a way to cut ROUND holes in the MDF. I had considered buying the circle jig from PartsExpress, but couldn't justify a $56 jig set--I hoped I could find a local one for cheaper. Unfortunately, I couldn't. SO, I decided that I pretty much understood the principle, and I would make one.
Grabbing a trusty spare piece of acrylic that was originally a lid to a small container, I marked out mounting spots for the router base, and then determined where each circle's centers would be in relation to the router bit, once each for the inner and outer circles.
The first hole caused some cussing, as I for some reason decided to try and "easy" cut first and cut out the inner circle first--which means the middle falls out and you no longer have a central pivot point...WHOOPS. Some cardboard and quick thinking later, I managed to wedge the circle back in again and do the outer circle.
With that done, the rest of the cuts were fairly easy, though for anyone attempting the same kind of project, I would suggest cutting the front baffle and the back plate in one go, so that they're exactly the same width. Same deal for the tops and bottoms, and the sides. I put the enclosures together with nothing but clamps and wood glue, and they're probably solid enough to use as step stools.
On the electronic side of things, I got all of the parts together, and constructed the first of the two crossovers from the components provided with the RD kit. After testing with an MP3 player and an old mixer board I had lying around, it seemed to be working fine.
Following some advice from Biff on HWC, I inserted a pair of braces into each cabinet for more stable sound. I also put the "finish coat" on one of my cabinets in the form of peel and stick vinyl laminate, as I knew that I wouldn't have the patience to get a good finish on the joins.
I also managed to get the first color coat on my baffles, though finding the stuff I wanted was a bit of a struggle. Apparently, there is no consumer-grade colored polyurethane to be found--something I found quite annoying. I finally gave up on big places like Canadian Tire and Home Hardware and went into a little paint specialty shop I often use when doing renovation and contracting. WOW. I should have gone there first. He gave me a high-gloss marine grade black polyurethane for the price of...on the house. He said that for such a small project, and for something he sells so little of, I was welcome to just use what I needed and bring the rest back sometime....Needless to say, he now has a customer for life. As a plug, the place is called Klein's Paint and is on Saskatchewan Drive and Retallack in Regina, SK.
Here is a picture of the baffle, still wet with the first coat. It ended up needing 2 coats, with some light 2000grit buffing in between. Great glossy finish, though.
It took me a while to decide what I wanted to use for fasteners, particularly for the speakers to the baffles. The easiest way would have been using particle board screws, but I've found that if you ever have to take them out, they may not hold particularly well when they're put back in. With that in mind, I decided to use bolts, but ran into a problem because I needed particularly small bolts; when I finally found them (1/8" pan-headed stove bolts) I had an additional two problems: I couldn't find t-nuts that small, and the bolts didn't come in black. For fastening to the T.V. stand, I went with 1/4" carriage bolts, but couldn't find them in black either.
The solution was simple: paint them.
While this created a few problems with threading the nuts on, some work with a wire brush and some solvent on the threads took care of it.
Because I couldn't get the t-nuts for the speakers, I was kind of at a loss. In the end (and I might regret it--though I haven't yet) I decided to hot-glue them to the back of the baffles.
That done, it was time to get everything wired up and put in the fill. The soldering went without a hitch, and after some trying some different levels on fill, I ended up using about a quarter of the bag of fill that came with the RD kit in each speaker; any more than that and the bass began to sound muffled.
That done, I glued and clamped the front baffles to the completed boxes. The paint is beautiful; All the fingerprints make the paint job look a little off, but the gloss is lovely, and works right in with my home theater.
Anyway, with the speakers together, the only thing left to do was to connect them to the T.V. stand. I drilled a hole in the bottom of each bracket and put the 1/4" bolt through, with a washer and a bolt at the bracket, and then again at the speaker's side. Inside each speaker was a T-nut for the bolt to fasten into. Here's a picture of the bracket:
Finally, here are the two speakers attached to the bracket, on either side of the T.V. Project completed!...or at least it was until I decided to do the surrounds and centre…
The speakers were definitely an improvement from the get-go, but they really began to shine after a few hours of use. The harshness/tinniness that I noted upon first plugging them in disappeared, and the sound became gradually richer.
The real test was putting them in front of my wife, who was clearly blown away by the improvement, and helped me make final adjustments to the fill in each speaker box to produce the richest sounding bass. This was particularly important when we fired up a few movies to evaluate their capabilities; both Phantom of the Opera and 300 sounded phenomenal. Sound effects (and particularly rain and arrows) were crisp and clear, and the bold dramatic music in both films filled the room in a way the old speakers never did.
One of the things I didn't consider was just how much of the dialogue in both T.V. and movies is pushed through the center speaker when using 5.1 surround, which made a new center channel speaker rather important, in addition to the new left and right speakers. I ended up solving this little dilemma (eventually) by purchasing another Recession Destroyer package and a few additional parts and building both a center channel speaker identical to the left and rights, and a pair of TM (one tweeter, one mid) bookshelf speakers--a variant of the TriTrix--to function as surrounds...but that's really another story altogether.
For those that may be interested in undertaking this project, expect to pay about $300 for the speaker pair; that includes:
-~$200 for speaker parts, including exchange rate, tax, and duty
-~$30 for a 4x8 sheet of MDF (of which enough was left to do the center and surrounds, as well)
-~$50 for paint and misc hardware, including bolts, nuts, glue, sandpaper, wire, and paint supplies (again, enough left of most to do the center and surrounds)
This, of course, assumes that you already have the tools, such as a tablesaw and router, available to use.
Would I do it again? Absolutely; and I might if I ever get my basement redeveloped into a man-cave...but I think a new sub will come first :)
Need another Nerdgasm?