Retrofit Stock Sub into '04 M3 'Vert with HK Sound?

[OneSwellFoop]

Does anyone know if it's possible to retrofit the stock sub into the spot behind the center back cushion on an '04 M3 convertible with the HK sound system (Business CD)? My car has the cold weather package, so I'd have to remove the ski bag, which is not something I'd ever use anyway. The bass is a little lacking with the stock sound system that I have, but I don't want a big aftermarket sub box back there taking up room.

[Hallerhan]

If you haven’t already, I would remove your backseat and see if your ski pass has a similar housing to this. This housing splits into two, I suspect the side closer towards the trunk (that the swinging sub door attaches to) may be different than the one you have with the ski pass.

It could be as simple as changing out this housing

[dilmorecg]

If you remove the swing open housing you can build a custom box in that area. Plenty of room. I would recommend getting a new amp to power if you go aftermarket.

If you want to just replace the speaker I dont think its possible. I just had mine all apart thinking I could fit a shallow depth 8" subwoofer to replace the stock one and I couldn't find an aftermarket one that was shallow enough to fit. The stock "box" that swings open is pretty shallow.

The 2 piece housing is kind of a pain to remove. I found the best way was to go through the trunk and pull down each side sticking a trim tool to hold the tab open while you get the other ones free.

[maw1124]

BSW used to sell a kit (which I have) ... maybe you can find one on the web. But I didn't pay enough attention to the install to see what they did. I think the whole skipass went away though.

Maybe their install guide here... BMW E46 M3 -- BavSound Amp Tuning.pdf can be of some help in showing you what you'd need to do. If you troll around on the internet long enough you may find someone selling theirs. I got lucky and found the whole kit (cabin speakers, sub and sub amp) on eBay for $600 back when they were selling them for double that (like 2012). It's a good system for plug and play, but something custom is just as good. Theirs was 10" sub enclosure, which is probably the largest diameter that will work in that enclosure.

maw

[dilmorecg]

Something like this is an option: eBay Link

[OneSwellFoop]

Thanks for all the responses, folks!

[poss]

I wouldn't bother with the OEM sub (better than nothing but not by much)

I fitted a 10" Rocford Fosgate 200W sub driver in the front of the ski pass by making up a bracket using the ski pass as a template and closing up the boot-end of the ski pass with carpeted wood.

The cavity behind your rear seats makes a decent ported cabinet and you lose no boot space! Sounds great (driven bty a 200w Clarion amp). Also did the Bavsound upgrade as the HK tweeters sound terrible (they have plastic domes)

[macaroni86]

I wouldn't bother with the OEM sub (better than nothing but not by much)

I fitted a 10" Rocford Fosgate 200W sub driver in the front of the ski pass by making up a bracket using the ski pass as a template and closing up the boot-end of the ski pass with carpeted wood.

The cavity behind your rear seats makes a decent ported cabinet and you lose no boot space! Sounds great (driven bty a 200w Clarion amp). Also did the Bavsound upgrade as the HK tweeters sound terrible (they have plastic domes)

You don't happen to have any templates left over from this, do you? I bought my vert with a system already installed, I love the audio quality. Only downside is the box for the single 10" sub makes my trunk unusable beyond a small duffle bag.

I'd love to make something like this and get some usable space back. What does the passenger side look like with the seats installed?