Single SI HT 18 build

32291 Views 72 Replies 26 Participants Last post by Billy13, Nov 16, 2018

Code Red

Discussion Starter · Jan 11, 2013

11

Hey. Thought I'd make a build thread of my new sub beings that I like reading them and maybe others do too. This is my second DIY speaker project, but I'm far from being much good at it. Im still learning woodworking and about as far from an engineer as you can get. I've been reading threads here and elsewhere for quite awhile now and have learned a lot. This is a great forum.

So I picked up an SI HT 18 on preorder, seemed like a good deal. I've modeled all of the 15's and 18's in my price range and decided on a single 18 in a sealed box. I know I lose some SPL down low compared to ported, but the simplicity of the build as well as knowing how a sealed box in this room sounds steered me in this direction. Im replacing an old Velodyne F-1200 which did surprisingly well. I think I'm fortunate to have some nice room gain here.

I went with a box with outside dimensions of 34"h X 24"w X 21.75"d. Using .75" thick mdf sandwiched to .75" plywood for sides and back. Double .75" mdf for top and bottom. Baffle is 2 layers of .75" ply plus a .75" layer of mdf for the front. All bracing is double .75" mdf. After calculating the bracing volume I end up with about 5.75 cubic feet inside. I know its probably overkill and will be heavy, but my design philosophy is if its worth building, its worth overbuilding.:T

Now for some pics.

Beer and power tools.

Tool Machine Toolroom Wood shaper Table saw

Gluing the baffle

Workbench Wood Table woodworking Tool accessory

ply from home depot. Had to squeeze a bunch of glue in and clamp up.

Wood Plywood Table Furniture Hardwood

Workbench Wood Machine Table Tool

Gluing in bracing

Workbench Wood Table Plywood Furniture

White Architecture Black-and-white Line Monochrome

Machine Machine tool Photography

Metalworking hand tool

Black-and-white Monochrome Machine Monochrome photography Photography

White Black Black-and-white Monochrome photography Monochrome

More pics to come.

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Code Red

Discussion Starter · #41 · Jan 19, 2013

7

Sanding day.

Product Subwoofer Audio equipment Loudspeaker Plywood

Wood Plywood Hardwood Wood stain Table

White Black Line Light Monochrome

Audio equipment Subwoofer Plywood

Time to roundover the side edges. I started with a 3/4" bit then moved on to the 1" bit. It went surprising smoothly.

Material property Plywood Architecture Wood Table

Audio equipment Subwoofer Loudspeaker Plywood Concrete

Thats it for today, if I get a chance tomorrow I'll get some primer on.

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txredxj

· #42 · Jan 19, 2013

would look really cool if you painted the mdf and stained the plywood with a glass top. looks really good

Code Red

Discussion Starter · #43 · Jan 19, 2013

Thats an interesting idea, too bad I used cheap home depot plywood, the stuff is really junk. Next time I'll source out some good stuff and pay the extra money.

Harold Dale

· #44 · Jan 19, 2013

Yea home depot has terrible "cabinet" grade ply. I don't know any respectful cabinet maker that would use that .

AudiocRaver

· #45 · Jan 19, 2013

Wow, really really nice work! Attention to detail! Reminds me of a cabinet I built decades ago for guitar speaker, only yours looks GOOD! (Mine did NOT.)

Code Red

Discussion Starter · #46 · Jan 20, 2013

6

Thanks audiocraver I appreciate that. As I start the finish, as it were, I realize that there have been some lapses in the attention to detail though. I knew that having the plywood showing with butt joints instead of designing with rabbet joints and having only mdf on the outside was going to create finish problems. Mdf and plywood just sand at different rates even using a hard sanding block. That and all of the screw holes. I knew this going in and opted for strength over a perfect finish beings that the sub will be behind the mains stuck in a relatively dark corner. The finish doesnt have to be perfect. Ill leave that for when I build some new mains and center.

Heres a shot of the back before I started with the primer.

Plywood Wood Box Furniture Pedestal

After the first coat of primer.

Product Wood Audio equipment Subwoofer Loudspeaker

I decided to use a good spackle to fill the smallest holes that the wood filler left.

Table Wood Plywood Furniture Material property

This is a better shot of it.

Audio equipment Subwoofer Loudspeaker Concrete

After sanding and another coat of primer.

Technology Electronic device Package delivery Gadget

After 5 coats of primer.

Subwoofer Audio equipment Loudspeaker Plywood

Ill probably give it a few more coats because you can still see the color difference between the plywood and the mdf.

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Harold Dale

· #47 · Jan 20, 2013

Yea MDF can really suck up a lot of primer. Looking great though!

chrapladm

· #48 · Jan 20, 2013

Looks great. Primer is always key in all my finishes.

Zestforlife

· #49 · Jan 21, 2013

Nice job. What primer are you using? Is it sprayed?

Code Red

Discussion Starter · #50 · Jan 21, 2013

I used Kilz 2 latex. I just used a foam brush as I didnt want to go to the trouble of making a separate spray tent in my garage, or move it outside. I didnt have a problem with brush strokes that even a foam brush leaves as it will blend in with the paint method I plan on using, and as I said before, the sub will hide in the corner anyway. I put it on vertically in long even strokes from top to bottom except for the top, there I went from front to back.
I painted the back today just to see how it will look and I think it will turn out OK. I'll post pics when I get it further along.

Bassluver

· #51 · Jan 21, 2013

very nice work...would this be considered overkill?
Thanks

AudiocRaver

· #52 · Jan 21, 2013

Bassluver said:
very nice work...would this be considered overkill?
Thanks

Overkill - isn't that one of the required characteristics of being an A/E enthusiast? "Overkill is in the eyes of the beholder?" "Overkill is the mother of invention?" "One person's overkill is another person's just good enough?" Just funning with you. It is SO easy to get carried away on a project like that. I still say the basic woodworking quality is to be greatly admired.

Code Red

Discussion Starter · #53 · Jan 22, 2013

Overkill? Yeah probably. I agree with audiocRaver, its all relative. I was looking around the webs the other day at speakers to get ideas for new mains I plan on building. I came across these: http://stereophile.com/floorloudspeakers/magico_q5_loudspeaker/index.html They are a modest sized floorstanding speaker that weigh 387 lbs each and cost about 60t thousand a pair. I realize that the importance of a dead cabinet is probably more important in a full range speaker, but even in a sub it just makes sense to me to make it resonance free as possible. Plus I just like making things really solid.

Also, I own a good hand truck.:T

theJman

· #54 · Jan 22, 2013

Code Red said:
Overkill? Yeah probably. I agree with audiocRaver, its all relative. I was looking around the webs the other day at speakers to get ideas for new mains I plan on building. I came across these: http://stereophile.com/floorloudspeakers/magico_q5_loudspeaker/index.html They are a modest sized floorstanding speaker that weigh 387 lbs each and cost about 60t thousand a pair. I realize that the importance of a dead cabinet is probably more important in a full range speaker, but even in a sub it just makes sense to me to make it resonance free as possible. Plus I just like making things really solid. Also, I own a good hand truck.:T

At 60 grand a pair you'll need more then a hand truck; you'll need a Brinks truck too. :rofl:

Code Red

Discussion Starter · #55 · Jan 23, 2013

4

Paint. I had a color in mind when I started this project, a dark gray-brown with a subtle metallic champagne quality.

Art Paint Sculpture Still life

It came out a little darker than the photo shows.

Big rubber feet.

Wood Floor Architecture Games Metal

Again its actually darker than the photo shows.

Plywood Wood Table

Tomorrow I hope to get a top coat on, then get the binding posts on and wiring done. After that I'll stuff it with poly fill and move it to my living room. Then pop the driver in and test it out. Beers will probably then be hoisted.

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Mike P.

· #56 · Jan 23, 2013

Nice cabinet!

brian6751

· #57 · Jan 23, 2013

Sweet! Looks great!

TheLaw612

· #58 · Jan 23, 2013

That looks great! What did you apply the paint with? Foam roller/brush?

Code Red

Discussion Starter · #59 · Jan 24, 2013

I use a wide soft artists brush. I use a water spray bottle to mist the paint while applying to control consistency. I apply in thin layers a section at a time and let that layer dry thoroughly before adding another layer. I brushstroke in the same up and down direction for each side. The result is a subtle faux wood grain effect that the pic doesnt show very well.

Owen Bartley

· #60 · Jan 24, 2013

Looks great with that big roundover (that doesn't actually seem big on this box). And I like the description of your paint colour, dark gray, brown, metallic... awesome. My wife says I like brown too much, but I don't think that's possible.

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