DIY Speakers - The Sealed TriTrix Set
I thought it was time to start a build log up. I've been working for a little while on a DIY project which I hope will result in a nice set of speakers for my home theater system, which is currently a reasonably unimpressive Sony HTIB.
My budget was pretty limited for this project, so upgrading the receiver was out, and an entire speaker redo was probably not going to happen. After some discussion, particularly with Biff on HWC, I decided that the thing to do would be to buy the TriTrix Recession Destroyer Kit from PartsExpress, and build the enclosures myself. That way, there was no need for me to design or tweak a crossover--which I had NO clue how to do.
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 I have 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 seems to be working fine.
Still waiting to be done is the filling, sanding, priming and painting of the baffles, and all but the painting on the rest of the cabinets, as I will be covering them with adhesive vinyl. I also need to assemble the other crossover, mount them in the cabinets, and put the holes in for the binding posts.
Back to work...
OK. I figured it was probably time for an update. I've been awfully busy with other things--particularly as I'm scheduled to defend my English thesis on Friday, but I've managed to get some work in on the speakers during my rest time, and I'm using this update as an excuse to stop reading for a while.
The electronics are now finished; both crossovers are wired, and have been tested.
Things are coming along on the finishing front, as well. Following Biff's advice, 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.
It came out OK, but not quite factory. For the second cabinet, I think I may try wrapping it the other way (working vertically on the cabinet instead of horizontally) to see if I get better joins where it will matter most--on the side facing away from the TV.
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. I don't imagine too many people live near me (as HWC seems to be mostly east and west coast ppl), but I had to say it.
Anyway, here is a picture of a baffle, still wet with the first coat. I think it should take two coats, with 1000-2000 grit "sanding" in between, and then some buffing to make it shine. If need be, I still have a spray can of clear polyurethane if it needs a bit more clear-coat after.
I post more once I get everything together...MAYBE after Friday, depending on how much goofing off I can justify during my defense prep.. :whistle:
Alright! They're done! But I'll continue with the play by play.
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...) 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. Here's the finished product:
Did I mention I love that paint? All the fingerprints make the paint job look a little off, but the gloss is BEAUTIFUL, 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. Though I didn't get a picture of it, I had a chunk of wood with a t-nut on the inside of each speaker box for the bolt to fasten into; I would have just used the t-nut on the inside of the box, but had no room to swing the hammer. 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!...At least until I decide to do the surrounds and centre. :biggrin:
They sound fantastic! :bananafunky:
It's not too often we see speaker builds here!
That's a really nice pink hot glue gun you stole (or I hope you stole) from the wife there :P
/subscribed... Looking forward to this build.
wow this is cool not something you see every day here great stuff
They are, however, MY fuzzy, black, beaded slippers...Fark my basement gets cold once the weather turns...
I had a pair of those 8 years ago.... they are pretty awesome.
Looking good. Looks like you breezed through the baffle construction which usually gives a lot of first timers some trouble. XO layout looks good too, again lots of first timers aren't aware of proper inductor placement. Good decision to make your own circle jig for the router. Homemade units are usually better than commercial ones especially considering what some commercial units cost.
While you have the chance maybe glue in some scraps of MDF in there for some braces. It's not about strengthening the boxes so much as deadening them. An experienced builder who was very adamant about bracing gave me the rule of thumb that the largest unbraced span should be no longer than your XO frequency. I haven't checked bu I'm assuming the XO frequency for those units is ~3kHz, that translates into a brace every ~4.5" on your flat panels. I think that's a little OTT but the reasoning is sound. The reason why is that the sound energy inside the box could (well actually it will) make the outsides of the box flex therefore transmitting sound, the frequencies that will be 'favoured' are those that have wavelengths that are whatever size the flat panel is, making your boxes sing and sing more at those select frequencies so colouring your sound and giving odd resonances. There's less energy as you go higher in frequency therefore past a certain point it doesn't much matter hence the rule of thumb. This is a large reason why you see odd shaped boxes and curved sides and such on some peoples builds, those somewhat ill defined distances and edges don't allow the box to ring like a tuning fork.
It's a small enhancement but it's free and pretty easy to do too so why not.
Keep up the good work! And more pics!!!
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