Translam RS150/27TDFC mains are complete!

Posted on April 4, 2010 by

DONE!  Crossovers, dampening and drivers installed, sounds amazing!

Listening impressions: I’m afraid I can’t really give these speakers a fair audition.  Not only am I novice with this, I also have an absolute horrible room for acoustics: laminate flooring and the couch is on the back wall.  Building these sealed, I have to augment them with a sub, so bass from my Dayton Reference 12″ is boomy (extension is impressive, but this room is making it boomy).  As for the flooring, I have a rug, but it’s not positioned to catch that first reflection point.  For the side wall first reflections, I have another couch (good) and a stone fireplace (bad).  I’m planning on treating the wall behind the speakers, behind the couch, and building a couple of bass traps, but right now the room is really hurting things.  In addition, the speakers are not positioned as wide as I’d like, so the sound stage feels kinda narrow.

All that considered, these things still sound awesome.  They feel very balanced and accurate.  I’m hearing things in music I didn’t know were there.  It gives me a whole new appreciation for the music I’m listening to.  I find myself saying, “Ohhh, that’s what it’s supposed to sound like, that sounds good!”  The tweeters are so smooth and don’t offend me at all, even with crappy recordings with no dynamic range.  I’m not a fan of metal tweeters (I probably haven’t heard any good ones), so these tweeters are welcome here.  The RS150s seem to blend well with the 27TDFCs.  CJD, whatever you did to design this crossover, I AM SOLD.  Midbass is tight and punchy and transitions well with the sub.  Well I’ll say it SHOULD transition well once I get my sub from sounding like I’m underwater and a whale is talking.  I was really worried about the low speaker height until I heard them and I can now comfortably say it’s a non-issue.  Anyway, as a novice audiophile that’s the best way I can explain what I’m hearing.

Now for some speaker porn…

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Center done, mains almost done – waiting on parts!

Posted on March 25, 2010 by

I know I owe you guys some sexy pics but this will have to do for now.  I’m just waiting for some parts that will be here on Friday, and I should be done this weekend, woohoo!

I finished up the center channel which will be hidden in the entertainment center behind grill cloth.  Here’s some snaps of the partial BSC crossovers for the RS150s and the 27TDFC.  They’re on MDF, 16 gauge wire between components mounted with hot glue.

The crossovers are mounted with velcro connected with 12 gauge speaker wire (monoprice).  The box has the dampening on the walls with a little bit of acoutica-stuff/polyfill/whatever it’s called in the enclosure.

I’m still waiting on the inductors for the RS150 crossovers for the mains, but I went ahead and put everything together.  Both the front and rear baffles are floated with screws through oversized holes and washers to allow for expansion.  Here’s a pic of the gasket before attaching the rear baffle.

The stands were finished separately: primer, black paint, polycrylic for the MDF and sealer with polycrylic for the BB ply.  After finishing, the pieces in the center of the stand were glued together with wood glue to make one piece.  It was then attached to the bottom and top pieces using screws.  I didn’t want to use any glue on that part in case I wish to make the stands taller later on.  The stands are attached to the speaker with 1/4″ socket cap screws threaded through the hurricane nuts already in the bottom of the speaker (see previous posts), with rubber grommets to create a small gap.  Rubber feet on the bottom of the stands for the wooden floors.

The front baffle is attached with wood screws that are screwed in from the rear by reaching my hand through the driver cutouts.

As for the rear baffle, I would have done the same as the front baffle if I could do this over.  Instead, I used socket cap screws visible from the back, but they weren’t very nice to the surrounding paint.  One of the bolts has a large standoff that I was planning to use to anchor the speakers to the wall or the entertainment center.  Now I’m not confident I’ll even use them, so that was a mistake.

Here they are in room.  They’ll be a little farther apart than this when all is done.

And here’s with the pull-down projector screen.  The center channel is behind all that grill cloth in the entertainment center.

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Almost there!

Posted on March 16, 2010 by

I’m in the home stretch! The mains and stands have been sealed and have a single coat of polycrylic. The baffles are cut, primed, painted (black), and also have one coat of polycrylic. I’m looking to do at least two more coats all around.

I’m happy with how they’re turning out, but I have just one problem… the enclosures got taller by about 1/4″!! I’ve been keeping them inside to aclimate to the house and then took them outside for a couple coats of shellac. They were outside for about two weeks, which is when it started warming up a bit here and getting some humidity. So I dry fit the MDF baffles on the weekend and they fit, but they’re about 1/8″ short on the top and bottom. The MDF is stable so it didn’t expand like the mains, doh! I’ll be keeping the mains inside for a while to see if they shrink a bit, but I’m not too optimistic because the molding in my house has even expanded with the weather.

It’s too late now to do anything. I’m not going to recut the baffles out of MDF because the box will apparently shrink in the winter anyway and I’ll be right back where I started. If/when I redo the baffles, I’ll use a hardwood and position it so it will expand and contract vertically and hopefully the difference is bearable. But that’s a long time from now unless I’m really displeased with how this turns out.

I’m not really concerned about ruining the enclosures with the baffle (as happened with a previously mentioned build) since I’m floating the baffles by affixing them from the rear with a big hole and washer. If there’s any movement, it should slide.

Now on to the pics…

Baffles cut for mains and center.  For the mains, I’m using hurricane nuts in the rear to mount the drivers.

I know, grills suck, but there are lots of kids in the house and it’s not worth taking a chance.  When the kids grow up, I’ll take the grills off, but I don’t want to be stuck with grill guide holes.  So I used a drill press to drill holes in the back of the baffle so that it drills almost all the way through to the front.  Then I dropped in magnets and sealed the rear with silicon.  Now the front baffle will look nice and clean, but will still hold a grill.  I was going to built my own grills, but I ended up ordering a pair of PE grills when I noticed my box is around the same size as one of their enclosures.

This is a shot of the rear baffle taken from the bottom.  The two side by side holes are for the terminals, while the holes in the center will be used to affix the baffle with socket screws.

Primed all MDF with automotive high build primer.  I love this stuff!  Parts of the stands are in there but it’s kinda hard to describe what it’ll look like.

Here’s the dry fit front baffle.  There is a small gap on the top and bottom from the box growing a bit due to the humidity.  I can barely tell in person so I think I can live with it.  The translam now has 2 coats of Zinsser coat, dry sanded with 220 grit, then 1 coat of semi-gloss Polycrylic.  I’m planning on two more coats and then I’ll see if I want more.  The picture doesn’t really do it justice.  I’ll take some glam shots once everything is complete.

Rear shot

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Tritrix translam now RS150 MTM

Posted on February 23, 2010 by

With all this work I’ve decided to ditch the Tritrix and upgrade to the MTM.  Considering the time and money already spent, the cost difference is pretty minimal.  The enclosure and baffle are identical.

Progress has been slow but steady as the weather hasn’t been great for working in the garage.  Here I drilled some holes for dowels using a drill press and template.

Drillling holes for dowels

For the bottoms, I drilled holes all the way through and used hurricane nuts so I can use these later to bolt the box to the stand.

And the next layer from the bottom is the brace, so the holes will be covered…

It’s been so cold outside I had to bring everything inside for gluing.  I did two layers at a time and clamped.  I tried three at a time but I couldn’t get enough clamp pressure to close everything.  Two layers was just fine with about 30 minutes clamp pressure.  The dowels help a lot with gluing.  Despite using a drill press and template to make holes for the dowels, it still wasn’t perfectly aligned.

Here are both enclosures glued with one sanded.  For sanding I started with 100 grit because it was the roughest I had on hand.  After 20 minutes of little progress and an arm that was about to fall off, I ran to the store and got some 60 grit which went MUCH faster.  The finished off with some 220 grit.  I applied one coat of Zinsser sanding sealer (sealcoat) on the inside before applying the acoustic foam.

This is the 3/4″ Parts Express sonic barrier.  Feels stiff and heavy duty, I like it!

I dumped the sawdust from the sander and mixed it with PVA glue to fill the voids.

That’s it for now!

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What to do now…

Posted on January 22, 2010 by

The speakers have to fit under the projection screen, and I’m concerned this might be too low and screw up the sound stage.

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Done with cuts for L/R mains

Posted on January 18, 2010 by

I’m finally done with the cuts.  It’s nice and dry out, but too cold for gluing.  I’m going to bring them inside and wait for a warmer day to start gluing.

Never have I dreaded so much cleaning my garage…

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Tritrix Translam Underway

Posted on January 18, 2010 by

When I first saw the Magico Minis, I knew I wanted to do a translam.  The Minis are crazy expensive and I’m looking for something on the other end of the price scale.  This is to be a 5 speaker setup for my family room, about 80 % home theater, 20% music.  After much research, I went ahead with Curt Cambell‘s tritrix MTM design.  It uses Dayton Classic drivers and appears to be pretty versatile, allowing  the enclosure to be placed vertically for L/R mains and horizontal for the center channel, all using the same crossover.  It’s a great bang for the buck from Parts Express.  The mains and center are to be MTM, while the surrounds will be MT.

I ordered 4 sheets of 4×8 Baltic birch plywood (B/BB).  Doing a translam, I suppose the most sane thing to do would be taking it to get CNC’d, but I had a hard time finding a local shop with a CNC willing to cut plywood.  I guess I didn’t look that hard (plus I like the idea of doing it all myself).

I studied quite a few translam builds from other folks, but decided to use the same approximate proportions as the Magico Minis while using Curt’s baffle dimensions.  I love the sound of sealed enclosures, and I’ll be using this setup with a sub, so sealed it is.  The resulting enclosure volume is a little more than Curt’s recommended sealed enclosure, but I’m trying to leave the door open for the RS150 MTM should I choose to upgrade in the future.  The baffle will be replaceable, so upgrading won’t involve rebuilding the enclosure.  And with a roundover, the baffle dimensions are very close to the tritrix.  This translam is going to take plenty of work so I hope the compromise doesn’t impact performance too much.

I took an overhead picture of the Magico Minis, then photoshopped it bit to get the right baffle width.  Here it’s traced on a peice of 1/2″ MDF.

Template outline

The toughest part was this curve.  I could have cut with a jig saw and then sanded, but I felt the router would give me something more accurate.  But with the changing radius of the curve, I went ahead and built a ghetto jig out of MDF.  Here’s the first pass.

jig

I couldn’t find the larger machine bolts for my router, so I used some nuts and bolts to keep the jig on…

jig_closeup

This is after about 12 passes on the router, changing from appx 4-14 inch radius to get as close as I could to that line.  I then sanded any transitions.  I’m impressed with the result as I didn’t have to do much sanding.

changing radius

For the front baffle cutout, I used two pieces of MDF for a straight edge and right angle.  I’m going to be using a 3/4″ MDF baffle, which is a little deeper than the Magico template.

baffle edge baffle_cutout_2

I transferred the one good side onto a new template, using the straight edge from the front baffle cutout to align the opposite side.

curve_transfer

I didn’t follow my original template for the rear, since I want it to have the width for a port should I choose to add one later (and the enclosure needs to be shorter for the appropriate volume anyway).  The rear is cutout for a 3/4″ MDF baffle also.

complete_template

For bracing, I looked at the layout of the Magico braces and ghetto-rigged some paint stir sticks to have something to use with my router.

bracing template

I transposed the templates (with and without braces) onto the Baltic birch plywood.  The MDF is really easy to work with, but it dents too much when using flush router bit to make duplicates.  I think the plywood will be more consistent.

templates_2

Finally, here are all four templates.

templates 4

The first enclosure took maybe 12 hours for the 30 pieces needed to make it ~21″ high.  Yeah, those are burn marks from the router on the non-visible parts.  When I wasn’t routing the outside curves, I got lazy with the router since I knew it wouldn’t be visible anyway.  Here’s the first box dry stacked, unsanded.

First enclosure dry stacked

I’m about half way through the second speaker.  The MT surrounds are going to use the same templates, but will be only 12″ high, so I might just keep going and get them all cut while I’m setup for it.  That way I can seal and finish everything at the same time.  When this is all done, I’ll make a crappy MDF box for the center to be placed in the entertainment center since I don’t have room on top for a horizontal translam.

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