[djrobx]

I pulled the left "hidden" storage bucket out of the lefthand side and the cover. I clamped them together, covered them in aluminum foil, and made a mold. Then I made the box in the mold. I chose the left (stock amp) side, because there's a lot of unused space there underneath the factory amp, and that bucket comes out easier. Once the back and bucket side were done, I glued a wood ring on some pieces of scrap wood then draped a T-shirt over it to give it the curved look, then fiberglassed over top of that.

This was my first time working with fiberglass, it's EXTREMELY messy. So glad I didn't have to do this in the car itself. I didn't take many pictures of the process because frankly, my fiberglassing skills are pretty poor and there were mistakes galore. There are a lot of things I'd do differently if I were doing it over again. I think I finally got the hang of it towards the end, which is fortunately when I did the front face. The bucket was a very painful shape to duplicate in fiberglass. Fortunately carpet covers a multitude of sins. The visible part came out pretty good, and it sounds great!

[///Mposter]

Cool idea. I haven't seen any of this on the x3 forums before. So did you just hook it up to existing wiring or did you add an amp , power, ground, and speaker cables?

[Bimar]

Curious the subs in your X4 are not gassy enough?

[djrobx]

Cool idea. I haven't seen any of this on the x3 forums before. So did you just hook it up to existing wiring or did you add an amp , power, ground, and speaker cables?

I bought a harness from Technic that sits between the factory wiring and the factory amp, so no cutting of stock wiring was necessary. It provides signal to my aftermarket Alpine PDX 1000.1 amp. Since the battery is located under the hidden compartment, the majority of wiring is super easy. The only trick here was finding a remote turn on wire, the X3 owners seem to have a little black wire that runs up the right side, that I didn't seem to have. I found a suitable wire under the rear seat (a thicker red wire with a gray stripe through it). The factory amp has plenty of power for the tweeters/mids for my purposes. The Bavsound component sets that I'm using up front are a bit more efficient than the factory speakers anyway.

Curious the subs in your X4 are not gassy enough?

Not for me. I've had aftermarket gear in every vehicle I've ever owned. The under-seat subs are able to provide a respectable thump for some music, but they seemed a bit strained doing so, and I was missing the deeper frequencies that I'm used to.

It's not so much about getting "more bass" but getting better quality bass, the same reason I replaced the HK tweeters to get better quality highs.

[Tjalle]

Since you have a carbon black 35i - same as me - I suppose you also do some driving at times?

In my old 9000 - I still have one - I installet 6x9 Infinity speakers in the support for the hatshelf, mated by a 2x200w amplifier. That did it for me!

[cesaroctavio_80]

Djrobx excellent write-up!!!

That's what in looking for I’m the happy owner of an X4 but I want to improve bass sound, so this is what in need.
I live in Mexico so I think will be not easy as was for you to get Technic harness. And I will outsource the fabrication of the sub box. But I’m thinking on doing whole installation.
Can you please share with us more information about your set up? Where did you locate amp? Where did you run wiring? How is the harness connected?
Can you take more pics on your setup?

Congratulations you made a great job
Have a nice day

[djrobx]

I put the amp in the hidden storage compartment between the tracks. I just made a small slice in the "tray" to let the wires through. There's tons of room in there and I doubt I'll ever use it for much else. You need to get under that tray anyway to do the other wiring, so it's the easiest place to put it. I figure it's nice to be able to access the amp easily to adjust the gain and crossover controls. There's also a lot of room under the factory amp, but I wanted to maximize the air space for the sub.

I'm sure you could get Technic's harness. I paid him by Payal and he shipped the set to me. Alternatively it wouldn't be that hard to tap into the wires. You'd only need to to tap four wires for signal (they go to the under-seat subs) and they're pretty easily identified because they're thicker than the other ones that go to the regular speakers. Then you need to tap a fifth wire for the amp turn on (you have to do this regardless of having the harness or not). That's on the passenger side and is a thicker red wire with a grey stripe. All of the wires you need to tap into can be accessed from under the rear seat cushion (the part your butt rests on ), which comes out really easily - just pull upwards from the front and the whole bench will pop out.

Tehcnic's kit came with an Audiocontrol LC2i which converts the speaker-level signals to typical aftermarket levels to feed the amp. You could just buy that item. The HK amp sends pretty high voltages to the sub so you need an active converter like the LC2i, I'm told the cheapie passive ones won't do.

You'd have to look at the harness that connects to the factory amp (which is where my sub is now) to identify the wire colors though. I'm using the technic harness, so I've never needed to map them. Since my sub is now sitting there it's harder for me to look at it without removing it.

Here's a picture of my sub amp (Alpine PDX 1000.1), and you can see where I attached the power wire to the battery (there's a bolt under that cover). To get to the other wiring to show you, I'd have to pull out that whole "tray". The tray is a flexible plastic so it's forgiving of having extra wire bundles routed around near it. My LC2i is by the factory amp behind the sub. I would have put that near the amp, but the included wiring connections from Technic aren't long enough, and the LC2i is very small, it was easier to to just tuck it back there.

If you're at all comfortable doing car audio installs you'll likely find this is one of the easiest you've ever worked on.

[cesaroctavio_80]

Thanks a lot. I'll let you guys know the advances. So far now i sent an email to Tehcnics web page and i got no response
Have a nice day

[djrobx]

I PM'ed him over on Bimmerfest forums. You might try that route. Good luck and do let us know how yours turns out!

[cesaroctavio_80]

Originally Posted by djrobx

I PM'ed him over on Bimmerfest forums. You might try that route. Good luck and do let us know how yours turns out!

Done, thanks for the Tip
I have a doubt using external components or a sub system like:

http://www.kicker.com/11PES10C

I have a planned trip to tucson AZ in a couple of weeks. So its a good oportunity to buy stuff

[djrobx]

Originally Posted by cesaroctavio_80

Done, thanks for the Tip
I have a doubt using external components or a sub system like:

http://www.kicker.com/11PES10C

I have a planned trip to tucson AZ in a couple of weeks. So its a good oportunity to buy stuff

That's certainly an easier route, and should work well as long as you don't mind losing a little cargo space. I almost bought a pre-built box myself.

In my case, my equipment is entirely moved from previous vehicles. The only thing I had to pay for was the harness and the materials to build the box.

[cesaroctavio_80]

Originally Posted by djrobx

That's certainly an easier route, and should work well as long as you don't mind losing a little cargo space. I almost bought a pre-built box myself.

In my case, my equipment is entirely moved from previous vehicles. The only thing I had to pay for was the harness and the materials to build the box.

Hi i changed my mind and I got an separate amp ( Kicker 500.1 ) and woofer ( Kicker CompRT ) so, I’m on my way to install aftermarket woofer / amp. I have same question about wiring.
I’ve done some research and configuration for PREMIUM sound is

Blue with red stripe (LEFT +)
Blue with brown stripe (LEFT -)
Black with red stripe (RIGHT +)
Black with brown stripe (RIGHT -)

¿Which is the one for HI FI sound?
Green/blue RIGHT
Blue/yellow RIGHT
Brown/white LEFT
Black/green LEFT

This is in order to get signal for the amp
Thanks a lot.

[djrobx]

This is where Technic's harness / advice helps. Has he gotten back to you?

You want to tap into the wires that go to the under-seat subs. As I mentioned I can't easily get back in there to look at the wires now that the sub is sitting there (and I have the HK system anyway). The most fool proof way to identify the wire is to look at the connector that goes into the factory amp (from what I understand the 20 pin speaker connector is the same on hifi / hk)

http://f30.bimmerpost.com/forums/sho...d.php?t=873325

There's a diagram of the connector there. The sub wires are thicker than the others so they're easy to spot.

[cesaroctavio_80]

Originally Posted by djrobx

This is where Technic's harness / advice helps. Has he gotten back to you?

You want to tap into the wires that go to the under-seat subs. As I mentioned I can't easily get back in there to look at the wires now that the sub is sitting there (and I have the HK system anyway). The most fool proof way to identify the wire is to look at the connector that goes into the factory amp (from what I understand the 20 pin speaker connector is the same on hifi / hk)

http://f30.bimmerpost.com/forums/sho...d.php?t=873325

There's a diagram of the connector there. The sub wires are thicker than the others so they're easy to spot.

Yep but the problem they dont ship outside of US
thanks for the advice, but the pin speaker connector is different from HK / hi fi, i already identified thicker wires, what i'm missing is the polarity. Maybe at the end i will have to remove front woofer to find out polarity.

[djrobx]

You don't really need to know the polarity. You can work that out by experimentation; you're probably going to need to anyway.

1) Connect only one of the the two underseat sub lines to your amp/LOC/aftermarket sub and play some music with the sub on but playing at a medium level. Make sure to close the trunk hatch and position the sub roughly how you intend to have it. Sit in the driver's seat and listen. Is the bass stronger or weaker? If stronger, your polarity is correct. You'll know if it's wrong, the bass will sound really strange and probably weaker than with the sub on. Try both ways, one will clearly sound better and stronger than the other.

2) Once you get #1 right, connect the second underseat sub connection to your amp (I'm assuming your amp will turn the stereo signal into mono properly). If the sub practically stops playing, you know the polarity on #2 is backwards. Just reverse + and - and you're good to go.

Nothing will be damaged by getting the polarity/phase wrong. It's just a matter of your add-on sub canceling out, or augmenting the the sound from the factory system. FWIW even with my harness, I had to hook my sub up with the + and - reversed to get the phase to match the under-seat subs correctly.

[cesaroctavio_80]

Originally Posted by djrobx

You don't really need to know the polarity. You can work that out by experimentation; you're probably going to need to anyway.

1) Connect only one of the the two underseat sub lines to your amp/LOC/aftermarket sub and play some music with the sub on but playing at a medium level. Make sure to close the trunk hatch and position the sub roughly how you intend to have it. Sit in the driver's seat and listen. Is the bass stronger or weaker? If stronger, your polarity is correct. You'll know if it's wrong, the bass will sound really strange and probably weaker than with the sub on. Try both ways, one will clearly sound better and stronger than the other.

2) Once you get #1 right, connect the second underseat sub connection to your amp (I'm assuming your amp will turn the stereo signal into mono properly). If the sub practically stops playing, you know the polarity on #2 is backwards. Just reverse + and - and you're good to go.

Nothing will be damaged by getting the polarity/phase wrong. It's just a matter of your add-on sub canceling out, or augmenting the the sound from the factory system. FWIW even with my harness, I had to hook my sub up with the + and - reversed to get the phase to match the under-seat subs correctly.

Tks a lot for the tips that's the way I will follow. Have a nice day

[cesaroctavio_80]

I think this is going to be last question haha can you please share a picture of where the remote wire is located? "I found a suitable wire under the rear seat (a thicker red wire with a gray stripe through it)" thank you

[djrobx]

Originally Posted by cesaroctavio_80

I think this is going to be last question haha can you please share a picture of where the remote wire is located? "I found a suitable wire under the rear seat (a thicker red wire with a gray stripe through it)" thank you

I'll try and do this tomorrow. But just pop the rear seat bench out (it comes out easier than you would think). Look on the passenger side and you can't miss the bundle of wires that follows along the side of the car. Find a thicker red wire with a gray stipe in it.

Suggest putting in a fuse close to where you tap also, since you will probably be running a thinner remote wire than the red wire.

[cesaroctavio_80]

Originally Posted by djrobx

I'll try and do this tomorrow. But just pop the rear seat bench out (it comes out easier than you would think). Look on the passenger side and you can't miss the bundle of wires that follows along the side of the car. Find a thicker red wire with a gray stipe in it.

Suggest putting in a fuse close to where you tap also, since you will probably be running a thinner remote wire than the red wire.

Thanks! nice tip I have everthing to install it, i'm only missing boxes for the woofer, once i have it done I'll install everything.
Have a nice day,

[puffins_00]

would you be willing to make another one or sell this one?

[BOSSBMW]

Does anyone know if the wiring is the same for the HK systems?