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Mission: Trio12 Sub (design/build)

25573 Views 54 Replies 19 Participants Last post by  Bengoshi2000
Today I submitted my order for the Quartet12/Trio12 kit. I've taken the suggested design and modified it a bit. Here are two pics from Sketchup:

The PR's will be covered with a cloth wrapped speaker grille... I'm thinking of using some of the "vintage" cloth that's available at PE (and elsewhere on the net).

I'm hoping to start the build in early November... pics are forthcoming.
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Awesome looks like a great start. This is really what I would like to try for my own set up. Especially the furniture look of the initial sketchup design. I love the idea of the finished end table that just happens to put out some awesome bass.
Egg crate foam is not an absolute necessity. Some say it works to dampen the back wave of the sub, some say it doesn't. Try it without and see how the sub sounds. You can always add polyfill batting later.
Finished the basic box today. Here's some pics of the progress:

Creative Clamping 101:

Joining some oak panels for the top:

I forgot my camera again and was stuck using my cel phone... GRRR.

Next step will be priming/painting the outer PR and Driver baffles. Then we start getting the finish pieces ready.

I still have high hopes of finishing this build by Thanksgiving!
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Looks good. I strongly suggest you apply glue to the perimeter of the T-nuts. You don't want to have any trouble with them after your components are installed.
They were dabbed with glue as we pressed them in... if they come out, they are going to bring some mdf with them. :yikes:
Just hit a remarkable speed bump...

Went back to my friend's shop yesterday to do some work on the sub. I noticed that the outer/bottom driver baffle (which was glued in place last week) was not centered with the driver baffle. It's centered perfectly with the box, but one or both of the circles must have been a hair off center to begin with so now the two holes don't match. It's off by about 7/16 of an inch (enough so that the driver won't fit).

Fortunately, my friend has a plan: We're going to take the router and enlarge/re-center the hole in the outer baffle with a jig (that features a slightly larger hole). I'll take pics when we do it.

Other than that, we started cutting the oak to be used on the sides and we continued working on the top.

Sorry no pics this time.

I'm starting to debate on finishes... I'm leaning towards hand rubbed tung oil at this time.
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Closer inspection of the driver outer baffle revealed that it was off by about 1/4 inch and the driver wouldn't fit. GRRRR. So I came up with a jig that would let us enlarge the outer baffle hole 1/4 inch off center. Here are some pics:

I took a couple of pieces of mdf and cut one piece to fit in the outer baffle opening, then we screwed it to another piece of mdf on the other side of the driver baffle. Then I re-measured for the center of the outer baffle opening. Then I moved the center hole 1/4 inch off center (to compensate for the error in the outer baffle opening. After that we adjusted the position of the router so that it would only shave 1/32 inch off of the side that had plenty of clearance and would take about 1/4 inch off of the far side.

The results were near perfect. You can see in this photo that the mounting holes for the driver are now equally spaced from the edge of the outer baffle opening (this was not the case before this operation).

A test fit with the driver revealed that it was now perfectly centered in the outer baffle opening.

Yesterday I re-primed the outer driver baffle and was able to get a coat of satin black on the outer PR baffles. It's going to be a few days before I can get back to it.

I don't think I'm going to make my goal of finishing by Thanksgiving!

Happy Tryptophan Day everyone!
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I like the fix, its pretty simple, but worked really well. i'll try to remember that in the future.
Whew... glad the Holidays are past. Between work, the Holidays, kids out of school and my own personal battle with h1n1, I'm finally back to working on this project. I'm doing some veneer work as we speak. With any luck, pics and descriptions will be up later today.
Here are the pics as promised:

I filled in the holes and lightly sanded the surface of the mdf.

Here's what I used to apply the veneer: TitebondII and a foam roller.

Here's the veneer drying. I first wet down the wood side of the veneer with a damp cloth, then rolled the glue on with a roller (the water helps the veneer lay flat... without the water applied to the wood side, it would curl when the glue is rolled on). I put on two coats in rapid succession and set it aside to dry.

I rolled the same two coats of glue on the mdf substrate. I let everything dry for about 45 minutes.

After both sides were dry, I put the veneer in place and taped it at the corners (only to hold the veneer until it was ironed down in the center).

I put an old cotton t-shirt on top of the veneer prior to ironing (to prevent the iron from scorching the veneer). I let the iron heat up to it's highest setting (cotton/linen), low steam, and began working at the center of the veneer. I moved slowly from the center outwards, keeping steady pressure on the iron. Once the center of the veneer was done, I removed the tape at the corners. Then I continued to work from the center to all edges.

I removed the t-shirt and checked the surface for any bubbles or other places where the veneer had not adhered... especially the edges (I didn't find any problems). Then I put the t-shirt back and repeated the ironing process one final time (again, working from the center to the edges).

I had cut the opening in the veneer (for the plate amp) so that it was about 1/4 inch smaller than the opening in the mdf. Once the veneer was cool, I worked with a veneer trimmer and 220 grit sandpaper to trim the veneer back to the opening in the mdf.

The results:

Now, it's ready to have the side/leg and trim pieces attached, then the top.

Stay tuned...
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Looking great!! our builds seem to have allot in common. I too have been having a hard time completing, Life always has a way of getting involved:doh:

are you planing on lining your box with anything? I am on the fence. Not sure if its nessasary with a PR box.

Mike P. lined his. I'm going to start out unlined... if I end up with anything weird going on, I'll add some batting or somesuch.

I'm liking your build, btw... that inlay is very nice.
I think I will try unlined as well at first. I sent CSS an email with his recomendations. Bob's response was not definative either way, So i suspect it is not that important with the PR's.
Did some more work today. The top is not attached yet, I set it in place just to get an idea.

My frustration is growing though... this build is going soooo sloooow...
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That's a nice looking sub.
Are you going to leave it that colour or stain it?
Are you going to leave it that colour or stain it?
I'm leaning towards a red oak / red chestnut stain and then finish it off with Waterlox Original sealer/finish.
your side slat detail work is very nice! really brings it together.
your side slat detail work is very nice! really brings it together.
I was going to say the same thing! I'm excited to hear how it turns out.
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