Custom Rear Deck Dual 12" Subwoofers! [+ build pics]

Hey fellas, ever since i saw that amazing Image Dynamics sub in 95SeriesBMW's rear deck, I was dying to throw one in my car. Problem was, that sub was a wee bit expensive for me lol

Here is where my journey began: one sub, in a white box, in my trunk:



I thought I was pretty clever with the placement of the AMP under there rear deck:



When I started this box, it was during the winter, so due to the cold weather, I figured I would just make a small temporary box until spring break when I could unleash my fabrication skills! Well, spring came and passed, and this ugly puppy was still in my trunk....

The day I got out of school for the summer (was summer after sophmore year at the time) I decided to begin!

Initial plan:


Then I figured...well if I am going to legitamently do this, I might as well go big eh? Why not two i thought?

So I ordered up my other sub, and a new amp to power both of them! These are two 12 inch RE Audio SE-X 12 Subwoofers, each putting out 600RMS, 1200 peak. The amp that replaced my older 1000 watt amp, was a new HiFonics 1500 watt mono sub amp.



Next, I decided what shape I wanted the box to take in order for this to actually happen. I decided on a box with a slanted top so the exposed subwoofers would peek through slightly tilted towards the cabin. The whole point of this endeaver other than crazy looks, was to increase trunk space (well.....that didnt happen lol cuz I have 2 subs inplace of 1), but nonetheless, I decided to make the box suspend from the rear deck to allow items on the trunk floor. I figured the bottom would be a larger rectangle to allow sufficient interior area. Next I cut out the two 12 inch holes for the top piece of the sub. I forget the measurments, but after I had that roughly done (i know the holes are not 100% circular in this pic, but I was getting antzy, so i finished sanding them at the final stage). Anyway, then I cut out a rough area from the rear deck. (no turning back now!)



I then made a "mock" box with sides just to test the fitment into the hole i had cut. Keep in mind this was after tons and tons of sanding, and dremeling:





Seemed to work well, and best part was, it was so snug that it was practically held in place that way (turned out that sucked alot during installation lol). Now for the support, I figured I would do something with corner "L" brackets of some sort. More on that later.

Now I decided to pull the trigger on the actual box. So after measuring once and cutting twice () I ended up with this bad boy (not secured to each other yet except the top):






Happy with my design, I screwed it together WITH SOOO MANY SCREWs! omg, i ended up going with 1 screw every 2 inches. OVERKILL Of course, I used wood glue and caulk afterwards. Final result:



Yay, looking good. Next I had to go to Ocean City for two weeks, so i mounted it in, and took a vacation with my BMW with no rear deck or rear seats Here is how i braced it in! Oh, and this was so ing hard to put it with the subs actually in it. Ended up haveing to use a combination of bricks and my OEM jack to get it into place lol.





Dont have a picture of this, but i have 4 brackets in the trunk also securing it (pics of it on finished product later)

No pics of this, but i makeshift threw my amp in the back and hooked it all up. Boy, It bumped! But there was a really obnoxious rattle of the wood squeaking against the sharp metal of the rear deck.

During vacation i ordered some matching trunk liner from autotrimstore.com? not sure, but something along those lines, under 5 dollars for 4 yards or so. Matched the color well, also got some HIGH QUALITY interior black auto felt to recover the rear deck, which i WILL be reusing That was almost 30 dollars, but well worth it. Here is a shot of the box fully carpeted. I used 3m 77 adhesive, and alot of it:

(yeah looks sloppy from this view, but thats cuz you never see this angle upon istallation)






Whuddup! Finally coming together. At this time, here's what I still had to do: the interior rear deck + sound dampening etc, and the amp + wireing. I decided to do the later cuz i was scared shitless of doing the interior lol

Decided to secure the amp to a piece of MDF secured to the back of the rear seats. No mine do not fold down......this was a huge pain in the 100+ summer days.... thanks for those record temps baltimore.....

But first, i must make the wireing neat. Here is something i like alot:

And now to make it supa clean:





Drilled into the metal behind the seats to secure the piece of MDF:


View from the cabin:


Screwed Amp into it as well, and routed the wires cleanly



Trunk COMPLETE lol:



Now onto the really obnoxious stuff..........the interor This seriously mad me lose sleep at night..... I was very nervouse that i would royally mess up the rear deck and have to shell out for another one. Lets see what happens

After about two weeks of brainstorming, I had thought up DOZENS of possible ways to do this. The most difficult part was the fact that the stock rear deck has a "trough" in it. In order to make it look neat, I thought i would have to basically delete this entirely. After test fitting the rear deck cover over the subs, the part of the box inbetween the subs, and really hte whole box itself caused the deck to push up ALOT in the middle. Now the middle of the two sub holes were cut out so as you can imagine, those middle parts stuck up because they were no longer connected. No pics of this. Then I decided in order to counter act this, I would construct a metal skeleton that would fit snugly around the subs, but would be fastened to the rear deck cover itself:

initial design + refinement:






Now on the subs with the deck: to give yyou an idea of what i was dealing with:



Next I glued it the bottom of the rear deck again with 77 adhesive:

(lol at my zip tied needle nose pliers?)



Note the aweful color of my rear deck. Yes, that is supposed to be black..... Now I used a fair amount of epoxy to smooth out the joints and add curvature to the rest of the side "troughs."



Now here it is after felting it with some top grade interior automotive material:











Whuddup! looking good! (minus all the dog fur etc)

Next I decided to put in epoxy and JB Weld in the areas where i could herar some squeaking from my vacation at the beach. I wanted to do this also to reduce road noise from the trunk, but I ended up not doing it 100% around because I had already used like 8 tubes lol:





Instead of spending more money on new sound dampening I simply reused the stock bmw sound deadening rubber as well as the foam. I used enough of the rubber stuff to completely cover all openings/metal.

Throw on the deck. Does it fit? Yes sir!





Then threw in the stock rear deck speakers (one legit has 1/4 of the outer most cone area completely disintigrated! its aweful and rattles, but I am going to grab some new upgraded BSW's in the future so Ill deal with it till then ) Here's how this puppy looks completely assembled!!!!

*****It looks so pimp when you look into the car through the rear windshield and see these bad boys, however, I got my windows tinted 35% (legal limit in MD) so that the sun wouldnt mess with my subs. As a result its impossible (at least with my iphone cam lol) to get a decent pic from outside in the daytime....... deal with the flash, sry guys









(no flash)






RESULT. I started this legitamently the day I got out of school......(May 18th) and finished about 1 month into the next school year (around September 30th)!!!

thoughts?

I gotta be honest. At first I really thought this might go downhill after I saw that picture will all your pliers zip tied to act as clamps, but... You did pull it off to be honest. That looks pretty damn good!! Congrats!

Wow! Looks great! How's it sound? Rattle a lot?

Originally Posted by ModBargains III

I gotta be honest. At first I really thought this might go downhill after I saw that picture will all your pliers zip tied to act as clamps, but... You did pull it off to be honest. That looks pretty damn good!! Congrats!

Same here.. i thought
Looks good Hope it sounds good too

Originally Posted by ModBargains III

I gotta be honest. At first I really thought this might go downhill after I saw that picture will all your pliers zip tied to act as clamps, but... You did pull it off to be honest. That looks pretty damn good!! Congrats!

Had 3-4 real clamps, and 3-4 pressure-clamp pliers. 8 places of contact didn't seem like enough, so i got creative. Whenever I bump em, I can't help but admire them in the rear view! Lol were the pliers really that off-putting?

Originally Posted by game-of-stance

Wow! Looks great! How's it sound? Rattle a lot?

Believe it or not, the only thing that rattles is my license plate, because it only has 3 of the 4 screws holding it on. These subs bump SO HARD. Obviously, it depends on the quality of the song, but for example: on "Two shots" off the carter 4, I can turn the base boost up all the way PLUS crank it up on the head unit, and it doesn't distort, just stops your heart is all

That is quite the setup and custom work. Good job on this!

Originally Posted by Halston@BSW

That is quite the setup and custom work. Good job on this!

thanks friend! If only I had a vert, then everyone anywhere near my car would be like (too bad I despise verts lol)

Not a problem. Enjoy... which I am sure you are!

Looks great

Nice job op! I want something like this but just in 10's. Is it hard to do?

Originally Posted by bimmerdriver1117

Nice job op! I want something like this but just in 10's.

Thanks man, it was def worth it. I love it

Originally Posted by bimmerdriver1117

Is it hard to do?

^lol wut? did you even read my post? I legit explained everything I did....

Very nicely done. At the start I was skeptical, but your results look superb you are also one of only a few who have mounted subs in the deck of this car.

One thing I noticed is that you bundled a bunch of your primary wire (battery +) up by the strut tower. Was there any reason for this? What you should do is cut it to length, I also noticed that you are getting your amp power from the main harness fuse. I would move the wire to the top post of the battery and keep away from the the abs charge and fuse that are installed on the cars primary battery wire.

Anyways, overall looks good!!

Originally Posted by okeydokey

Very nicely done. At the start I was skeptical, but your results look superb you are also one of only a few who have mounted subs in the deck of this car.

One thing I noticed is that you bundled a bunch of your primary wire (battery +) up by the strut tower. Was there any reason for this? What you should do is cut it to length, I also noticed that you are getting your amp power from the main harness fuse. I would move the wire to the top post of the battery and keep away from the the abs charge and fuse that are installed on the cars primary battery wire.
Attachment 422539
Anyways, overall looks good!!

finally! constructive criticism. Thanks. Hmm, I agree that I should have cut the power cord to length. I guess it slipped my mind because I wasn't sure which way I was going to route it etc. and before I knew it, I had closed everything up.....

as for the point of contact, if you open up that black box, it has the power cable from the battery attached to a post and then it has a bridge to a giant fuse that the power cable to the front (+) terminal connects to. I attached my cable on the batter side, before the fuse, so its really only extending the power cord to the amp a few inches. Since its on the battery side of the fuse, its all good, and looks way cleaner than routing it from the battery (lol even though all that is hidden)

Looks so good man!

Nice work. You must be an engineering student. I have a single 10 powered by 400rms in my X5 that will shake the rear view and make your hair vibrate. I CANNOT imagine how good those RE's sound in a little E46!

Great job on the install. I have been brainstorming on how/where to mount my sub. I would love to mount it on the rear deck like you did.

To fix ur liences plate - just un screw n shove a napkin behind it is it is tight when screwed back on. Cheapest sound deadening on the planet and works everytime.

I came up with that one long time ago. It always makes me laugh when I hear a plate rattling when the fix couldn't b easier.

Keep enjoying ur tunes.

I also was a little skeptical, it turned out pretty clean from the inside, not super excited about how it looks from the trunk, but you gotta make sacrifices to get a great sound system.