Mazda 3 - AKA how much can I cram into my trunk - build log with LOTS of photos!

[ancorp 10+ year member]

So I thought to myself - what's the biggest friggin box I can fit into my Mazda 3 trunk without having to build inside? With the help of some old (mostly Soviet era) tools, and on occasion my old man, here we are.

Old setup:
 
HU:
Pioneer AVIC Z110
 
Doors:
Infinity 6030cs components in front
Pioneer 6x8s for rear fill
Rodek 2150i amp wired at 1.3 ohms per channel
 
Trunk:
Two American Bass HD12D1
3.8-4cubes net @32hz
Two Clarion DPX11500 strapped at 0.5 ohms each
 
Batts:
Two Optima Group 35 yellow tops
 
 
New setup:
 
HU:
Pioneer AVIC Z110
 
Doors:
Four Alpine 6.5 SPS-610 per door in front
Alpine SPS517 6x8s for rear fill
Two Sony 4 channel 1995 old school XM-450G at wired at 1 ohm per channel, one amp per front door (125w RMS per speaker - 1000w RMS for front doors total)
Two Audiocontrol 30 band EQTs one per front door
Sony XM-752EQ 2 channel with built in 5 band EQ for rear doors
 
Trunk:
Three American Bass HD12D1
7 cubes net @32hz
Two Clarion DPX11500 wired to 0.33 ohms each
 
Batts:
Kinetic HC1400 in the front, Odyssey PC2150 in the spare tire well.
So, on to the photos!

Out with the old batts, in with the new.

Out with the old front stage.

Click to read more...

 

[ancorp 10+ year member]

In with the new amps/EQs. Note the quick and easy under seat "amp racks" and the extended power/remote cables for the EQs so they can be quickly unscrewed and adjusted without having to unplug anything.

 

[ancorp 10+ year member]

In with the new door panels. The panels were done by a local shop (thus no photos of them being made) as I didn't want to experiment with fiberglass and resin, nor cutting my door panels myself for the first time. Added a couple of runs per door of some decent speaker wire as well.

 

[ancorp 10+ year member]

Cut out the main walls of the box and screwed together with a couple screws for a test fitting. The front baffle is slanted 10 degrees to squeeze out some extra airspace behind the seats.

Always good not to have to change bits.

Test fitting in trunk.

Battery sticks out of the spare tire well by about an inch so...

 

[ancorp 10+ year member]

Front baffle preparation. Didn't have the ports yet so cut out just the speaker holes. Decided on 7/16" threaded rods (had them laying around) as front to back bracing with decorative nuts on the front.

Some work with a good old Soviet "Rubanok" to make sure the baffle fit flush, as the cuts aren't 100% accurate with the old table saw I have.

Added some top to bottom MDF bracing as well - the box is now PL glued and screwed together except the top.

Couldn't decide on wiring configuration so decided to run 8 guage out for every coil.

All the time spent in the garage doing this is accompanied by some music played by my old little ghetto blaster, inspired by lack of good sound at local parties back in the day - Two JBL 6.5s, old sony XM 4 channel amp, 20 amp 12V modified computer power supply (with resistors on the 5v line to keep the 12V output stable), an AALC volume knob, and a pair of Clarion 12s bridged on the rear channels (I basically run whatever subs I happen to have sitting around with it). Great garage stereo that's been playing for years.

 

[ancorp 10+ year member]

The 3rd American Bass HD12D1 arrives! Stiff as hell as usual, a bit of a break in is required.

The ports arrive from Creative Sound Solutions! Picked up some sonotube from Lowes (and polyfill to stuff the doors, gorilla tape, and some plastidip for the box). Tuned them to 32hz. Had to cut a notch for the rear flares to rest on the bracing, wrapped the area in some soft window gasket tape so they don't rattle. The rear flare will have to be attached once the box is already assembled 100% and in car, then subwoofers inserted, then ports pushed flush. Only way it'd fit.

 

[ancorp 10+ year member]

Test fitting on the baffle. Can you say tight fit?

Top cover finally glued and screwed - box is solid.

Test fit take two - **** that port sticks out quite a bit. Will have to make sure to add some wood around it so the seats don't rest on the flares. Or sink the ports deeper, but will have to cut the port face so that it doesn't hit the surrounds of the subwoofers... will decide this later on.

Plastidipped the back in hope of some weatherproofing (trunk leaks rain water a tiny bit somewhere from the top) and spray painted the rest black.

 

[ancorp 10+ year member]

Wood filler on the screws (which were all counter sunk of course), spray adhesive, and then vinyl from Fabricland that matches the door panels, with staples along the edge.

Now where the heck will the amps go? No choice but on the box, but feet made with 5-6 layers of rubber matting to help with vibration. The amps are so big that a removable extension will have to be added to the box, painted red as I ran out of black spray paint.

Final fitting. I can't believe the trunk lid still closes just fine.

 

[ancorp 10+ year member]

Time to plop everything in!

And that's it! Gets very nasty on the lows! Haven't thrown it on the meter yet, but will eventually. Also videos will be coming in the next few days, these bastards flex the poor Mazda like there's no tomorrow.

Next upgrades:

Deaden, seal, and polyfill the front door panels (already picked up deadner and polyfill)

Possibly sink ports deeper

Clean up wiring in the trunk

Add trunk speakers (crowd pleasers), either Alpine 6x9 or 5.25s (own both, might as well match the rest of the alpine speakers in the system)

Singer 260A alternator

Third Clarion DPX11500 amp, to wire each sub at 0.5 ohms per amp

Move the Kinetic HC1400 to the back behind the right wheel well, add another battery up front

 

[Beau M 10+ year member]

Whoa! Nice work!

 

[BoomTaco64]

nice fitting it all into the trunk. the yellow top battery will be better for the car if it is under the hood and not the kinetik. the kinetik batteries were designed to be within 6' of the amplifiers and not designed to be under the hood batteries. how does it sound?

 

[ancorp 10+ year member]

Thanks guys. That kinetic will likely end up in the trunk anyway. Sounds great, really pounds the 25-40hz range. I may raise tuning to 35-37 or so, but the way it is now, its flexing the crap out of everything.

 

[BoomTaco64]

is the box just stuffed into the opening or is it sealed off from the trunk?

 

[ancorp 10+ year member]

Just firing in, not sealed off at the moment. I'm considering it, as it should help keeping all the pressure in the cabin as the trunk does flex quite a bit even with so little open area left around the box.

 

[ancorp 10+ year member]

A bit of footage for now.