Aftermarket sub/amp DIY

I didn't take a whole bunch of pics as I figured anyone who would tackle this should be able to remove the trunk liner and ski boot without visual aids.

1. Remove ski boot. There are 4 plastic tabs on the seat side that pop out. These are what hold the boot material to the door frame. The the door and trunk-side frame unsnap.

2. Pull floor carpet, tool tray, rear plastic trim on the rear side of the trunk and the left side panel. Your Bose amp will be under that.

3. Disconnect the large connector on the front of the amp and remove enough tape to separate the twisted pairs of wires.

4. Your factory subs are paired as follows:

+ Left = Brown/Yellow; - Left = Red/White
+ Right = Brown/White; - Right = Red/Blue

5. Once you located these, tap into them. I soldered and put heat shrink and then taped it up, but you could use splice connectors if you want. These are high level inputs. I used a cheap amp for now that has high level inputs, but I'll replace that with a pair of high to low level converters and a Rockford Fosgate amp this weekend.

6. Reconnect connector

7. Tap into the battery + as you can see in Pic #9. The yellow connector on the large cable is where I tapped it.

8. Pics #7, 8 and 9 show where I tapped the amp power on connector. This Green/White striped wire on has power when the ignition is ON. People have had some battery drain problems by using an accessory powered source.

9. Run both of these wires with the battery wire running up under the front foam piece and exiting to the left side just in front of the tie down loop.

10. I pulled ground off the lower mount of the factory amp as you can see in Pic #11. Make sure you scratch up the paint so you get a good connection.

11. Zip tie everything up and leave enough wire to reach the amp and allow you to pull the box back (if you ever want to pull it out) without ripping the wires out

12. Build you a box. I built mine out of 3/4" MDF and covered it with black felt. The speakers needed 1.25 cubic feet each for proper tuning. So using my mad math skillz figured out what size I needed. I wanted to make it as shallow as possible so I made it a tall and wide as I could. It ended up being 18" H x 30 1/2" W x 10 3/4" deep. I added 2 inches to the sides in front to keep it off the seat back and give it a bit of room to blow out the ski boot.

12. Seal it up with silicone/caulk and put some baffling material in there and your ready to go.

13. Mount the amp, hook up wires and bump away!

14. My amp is temp so don't knock the install yet. I'll run the wires through some plastic wire cover and clean it up after I install the new amp. But for a cheap amp I still could only turn it up 1/2 way before my ears hurt.

I may make a grill for the front of the ski boot, but it pounds through it now pretty well. If anyone has any questions, feel free to ask.

That is a great writeup, well documented. It actually looks very simple. I would probably make a cover of some type for the ski boot area, something with holes that you just put a black cloth over to pass the bass.

Originally Posted by tampamark

That is a great writeup, well documented. It actually looks very simple. I would probably make a cover of some type for the ski boot area, something with holes that you just put a black cloth over to pass the bass.

Thanks! I may do that, but even with the cushion in place, it definitely thumps the back of the front seats lol

I think I may just cut holes in the ski boot instead of removing it entirely. That way there is some support for the cloth cover. Post pictures when you get your permanent amp installed. I am sure it sounds great!

Have you considered filtering the factory sub's with a crossover? I will probably do this install and limit the factory sub's to mid-low band, cut out the real low and devote the aftermarket sub to providing the punch.

Excellent write up 30yrVetera. You make this seem so easy. I think I'm going to try this myself but use just one sub woofer instead of two. I like the sound now but sometimes can use a little more deep bass at times. Thanks for sharing this

damn i wish i woulda seen this before i spent 3k on a custom install. good work!

Hi,

Thanks for taking the time to do this, it has been a very useful start. I want to do something similar, but also want to tap into the rest of the cars speakers as have multiple amps ready to go (I will then decide whether to upgrade those as well). You give the colours for the sub inputs into the amplifier, but do you also have a listing of all the others?

I have not yet been able to find this info and am a little uncertain as to how many input / output channels the existing amp has......I assume it has four for front left, front right, rear left and rear right plus a fifth for the subs?...but there is also a centre speaker, so where is that powered from (NAV only?).

Hope you can help - thanks in advance.

Take a look at the wiring diagram

Originally Posted by TxTaz

Take a look at the wiring diagram

Hi,

Thanks - that's useful . For anyone following this, I also found the link below which was useful in understanding the wiring diagram:

http://www.bmw-planet.com/diagrams/r...46/symbols.htm

It looks like the centre channel speaker is on its own channel, which I was not expecting - are you able to confirm that for me? I thought it might be bridged across the left and right channels rather than having its own.

Finally, do you know where the crossovers are - built into the amps or at the speakers themselves?

Thanks again.

The center channel is a seperate channel. It can be turned off.
The x-overs are at the speakers, so in the doors and back side panels.

TX, I really appreciate the help on the lenses. I tried and tried to google to no avail. Thank you.
JD

You're welcome.

great write up. im picking up everything today.

Taz, do you have any idea on how to replace the rear tweeters in the 05 coupe?

On my e60 I had a fuse holder running 40M in between battery +
And I had a kill switch in between the remote wire... this is a good idea for me because I didn't want the subwoofer on all the time.

have you or anyone else found any issues with mad vibration noises and rattles??

i put in my 12" earthquake in the boot and it made more rattles than clean bass so i have now taken everything out and put back to standard