Building a sealed sub box

**muhhan** · 28-02-2006 12:13 AM

Disclaimer: The following is provided as a GUIDE ONLY, and neither myself nor Ozhonda take any responsibility for the outcomes of someone else doing the following. You follow these steps at your own risk!

Aim: To build a sealed sub box for a Alpine 12-inch sub that fits in the boot of EK civic

Required: Tools - jigsaw, table saw (optional), sanding block, coarse grit sand paper, file (optional), drill and 3mm drill bit, screw driver, rotary tool
Materials - 18mm MDF board, 8G x 40mm countersunk timber screws, wood glue, silicone sealant, Kwik Grip or spray adhesive, fabric

Steps:
1. Plan your design. Draw a scale diagram and measure to make sure its going to fit. Take your time at this stage, it'll make things run a whole lot smoother later!

2. Draw the individual pieces onto your MDF board.

3. Using a table saw, if you have one, or a jigsaw cut out the pieces as close to the lines as possible. Don't cut over them, you can always sand it back if it is a little big, but you can't add to it if you cut too much off. NOTE: When doing this you should wear safety glasses and a mask. Dust flies everywhere!

4. Sand back the pieces so that they are the correct sizes you drew up.

5. Test fit the pieces.

6. Mark out the speaker hole using a template or the speaker itself. Again, it's better if the hole is a little too small than a little too big otherwise you're going to have air leaking out.

7. Using the jigsaw test fit the sub. If it doesn't fit flush than sand down the edges. A rotary tool is perfect for this. Be patient, it took me about six times before the speaker would fit.

8. Pre-drill pilot holes for the screws using the 3mm drill bit. You probably only them every 10cm, I just got a little excited!

Screw your screws in so that the tip is just sitting flush with the first piece. This makes it easier when you start screwing it together.

9. Run a bead of wood glue on the joint before you put the piece into position and start screwing.

10. I like to continually test fit the pieces as I go to make sure that everything is working out. Here you can see that the front piece is not screwed on yet.

11. After you've got most of the pieces into position apply some silicone sealant to the seams. This will make it airtight.

12. OK, back from my break now. Now's a good time to get some sound deadening material in there while you can still fit your mitts in. This step is optional. Cut the material to size.

Stick it on using spray adhesive or Kwik Grip.

13. Fix the final piece down. The box is essentially completed. Notice all the sound deadending goodness inside.

14. OK. Here's the final step, carpetting the box. You can pretty much choose any fabric you like, I used polyester fleece. Cut the fabric into the rough size for your box. Here you can use spray adhesive. Spray onto both surfaced and wait until it goes a little tacky then place the box on the fabric. I started from the bottom and pulled the fabric around gluing each side as I came to it. Just make sure the fabric is pulled so that no wrinkles or creased are in it. After leaving it to dry trim the excess off using fabric scissors and cut the hole for the sub using a blade.

Other comments: Sorry about the lack of images I only thought about doing a DIY half way through the project. Thanks for reading!

**amurray** · 07-03-2006 07:12 PM

HEALTH WARNING

Guys.. just a heads up.. MDF was banned on building sites in brisbane because it can have the same a effects as aspestos ( stuff that gives u cancer ) so ALWAYS WHEN USING MDF WHERE A RESPORATOR AND EYE PROTECTION AT-LEAST and have a show straite after working with the stuff...

**zorrt** · 09-03-2006 05:41 PM

wow wat a nice professional box
mine is just a square and all crooked but it works well ahahah. Didnt make it triangular cuz got stressed out trying to work out the volume of a triangle then adding it to the rectangle part then having to plan it all out.

Where do u get the sound deadening from?

**nugget666** · 09-03-2006 06:07 PM

Originally Posted by amurray

HEALTH WARNING

Guys.. just a heads up.. MDF was banned on building sites in brisbane because it can have the same a effects as aspestos ( stuff that gives u cancer ) so ALWAYS WHEN USING MDF WHERE A RESPORATOR AND EYE PROTECTION AT-LEAST and have a show straite after working with the stuff...

maybe a mod should edit it with the following warning.
\

good write up though.

**amurray** · 09-03-2006 08:41 PM

not many people no about that with MDF.. but yes anyone who wants to post a DIY with MDF in it should add that..

also if u dont do the maths on the sub mox dimmensions #1 ur lazy #2 u can get programs to do it.. there are heeps

**muhhan** · 10-03-2006 12:35 PM

yeah, working in your backyard is a lot different than working in a fully set up workshop like i used to have when i was at school cos they've extractors on every machine so you don't have to worry about dust flying everywhere.

I got the sound deadening from jaycars. it isnt the adhesive type but it only cost about $11.50 for a piece 300mm x 700mm where as the foil looking adhesive stuff cost about $23 for a 300mm x 300mm piece.

During the planning process I extensively researched the dimensions of the box and used a freeware program called speakerwork to find the dimensions that would give me the recommended volume from the alpine instructions.

**dfekm3** · 16-03-2006 05:41 PM

loved it how u got someone else to do ur work while ur on a break.. LOL
good work mate

**muhhan** · 13-05-2006 07:10 PM

Just a note to let you all know how the box finished up. I drilled a hole in the back to run the speaker wires through and then sealed up this hole with silicone sealant. Soldered banana plugs onto the wire and hooked it upto the sub. Mounted the sub in after drilling some pilot holes and making sure it was all nice and straight. It looks hell sweet, i reckon anyway =) Can't wait to get this mother sucker pumping! Mum's not going to be happy! haha

**STARTSat7** · 23-03-2007 10:27 AM

im a shopfitter any 1 want a sub box pm me ill make you a perfect square cut outs etc mdf/hmr whatever you want.

**serpo** · 16-04-2007 08:37 PM

Originally Posted by STARTSat7

im a shopfitter any 1 want a sub box pm me ill make you a perfect square cut outs etc mdf/hmr whatever you want.

dude I read that too fast and thuaght it said" im a shoplifter.." lol, a quick question to all how thick should a seald double box be for 800W 10" subs???