Did-it-myself custom box for 370z (56k beware)
 

I've been driving this setup around for about 3 months. I was anxious to post up pics in the beginning but did not due to the nature and extent of the extreme install. I by no means provided enough proactical breathing room for the sub; basically the subwoofer is sitting in a .2cu foot box, which is way undersized for its specification. i didnt mind this because I was aiming completely for a totally stealth installation and was willing to sacrafice sound quality for usability. To further complex the enclosure situation, I'm actually overpowering this subwoofer by 225%. The sub is rated for 250w, and I'm giving it 600w from a clean class AB PPI PC2150 (150x2, 600x1) old school amplifier. I snapped one pic of the amps, for which I have not fully completed stabalizing permanant location. They are wedged into the space in front of the spare, and are locked and tied in place by a series of heavy duty zip-ties and bungie cords. I will somday go back and re-do this area, but for now its running just fine.

The box is built out of MDF pieces I bought from Home Depot. i jigged out the layers just about as large as the spare would fit, sandwiched and screwed the layers together and wedged the subwoofer inside. The sub is a 10" Pioneer Flat piston shallow mount woofer with a 3" mounting depth. The box is 3.25" deep and barely tips the scale at .2cu foot.

Support/hold downs for the box consist of 2 pegs which slide into the spare tire's lug bolt holes. This prevents the box from sliding, twisting, and turning. Then bungies wrap around the box from the spare to prevend the box from jumping and rising. Its a little rigged - I know; but very cost effective solution

The spare tire was dropped 1/4 inch by removing the rubber shims under it. The wing-nut was removed in favor of a recessed bolt/mount to provide more depth space for the sub-box. To remove the spare, I now have to keep an extra tool in the car as you can see in the second pic on the right.

The grill is also shop-built for purpose. Its 16 gauge perferated steel is firmly glued to a 1" thick, 12" diameter MDF surround and can support my weight of 170 pounds.Without further ado, the pics!!!

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If I had to do it all over again, I'd probably build the base sandwiched pieces of the box using 12" MDF rings easily found on eBay such as this:

12" 3/4 MDF Round Speaker Sub Rings Pair Fiberglass NEW - eBay (item 150361343148 end time Nov-16-10 10:31:03 PST)

Here is a picture of the Pioneer flat 10" sub
http://www.caraudiocentre.co.uk/prod...r_tssw841d.jpg

Doing this from memory, but isn't that sub designed to work in a box as small as .3 cubic feet? You are not off by much. In looking at your box, did you maximize the interior size by making the walls as close to the sides of the spare as possible? It looks like you left yourself some room there. This same type of box was done a while back and the guy cut circles and screwed/glued them together to make the cylinder. His circles fit right to the edge of the spare, and I believe he met the .3 requirement for internal volume. I like your approach though, as well as his. This is how I will do my sub when I get around to updating the stereo. I want stealth as well as all the usuable trunk space. He claimed his box hit pretty hard and was a good match for rock music (used the same Pioneer thinline).

I did make about an inch of space around the inside of the box for increasing the box's volume slightly. I think if I used 12" MDF surrounds instead of handy-cut pieces it would have probably been a little cleaner and closer to .3cu. I actually had spare MDF from another project and worked with that I could and a jig saw. I thought the easiest way to make the box at the time was with octagonal pieces, but if I had to go about it again I'd just make the pices 12" round.

Another idea I was toying with was using fiberglass to mold a box inside the spare; but this was a much easier approach.

My system is best when playing techno, and good with Rock / pop. Anything below about 40hz gets hardest for the box to re-produce and therefore this setup is not ideal for hiphop and rap. I have heard the new Pioneer IB Flat woofers which replaced the line I used fares much better below 40hz.that being said, this system is the stealthiest I've seen in a 370z, and the best I've heard - mainly because the amps are so good though.

The neet thing I've been thinking about; since this box is not dependant on the Amp's installation location I was thinking of making an alternate and much larger waveform style box with a single 12 in place of the spare and tools. because I saved so much making this first box I

did you stuff it full of polyfil?

It looks good but your sub will not last long with that much power in that small of an enclosure. Fiberglass is your friend in this application and it will buy you some more air space. You might even gain enough depth to run a better, more capable conventional sub. That is a great amp you are running but it will rape that 10" sub you are using. Some tricks I have used when running to big an amp to a small under rated sub is trying to wire it at 8 ohms if you can. To do so the sub would have to be a DVC with 4 ohms per coil but then you can run a 600 watt amp and the sub will only see 200 to 300 watts but you have a massive amount of reserve for the amp to deliver clean power to it.