How To Guide 5 Series Under-Seat Subwoofers in a Z3

David

Zorg Guru (III)
Supporter
British Zeds
Joined
Sep 16, 2013
Points
133
Location
Shoreham-by-Sea, West Sussex
Model of Z
Z4 3.0si Sport
So, a little while back, I started considering my options for improving the sound system in my car, for as little money as possible.

Well, today I made huge progress with that by installing some BMW 5 Series E60/61 under-seat subwoofers into my Z3, while my seats were out as part of my ongoing refurbishment of my Z's Interior. Here's the story:

I spent a couple of days pondering and trialling the best placement of the subs, and unfortunately, I wasn't actually able to fit them under the seats. :(

I found the subwoofers on eBay a while back, and for a long time I was asking on 5 series forums about what sort of amp I will require for them. I EVENTUALLY received a response from a member (no way near as insightful or friendly as this forum), who said they are rather weak, and that is be better off upgrading them...

I was disheartened by this news, but after thinking about it, I figured this was actually exactly what I wanted... The Z3 has a tiny cock......pit compared to the 5 Series so they'd suit the space better, AND (remember how I said I was on a budget) this would mean that I wouldn't necessarily require an amp to power them.

So, I decided that I was going to splice straight into the stock rear speakers' wiring, which I did at the head unit to save having to tear the interior apart.

I decided the easiest (and least destructive) place to fit the subwoofers was behind the seats on the back wall and, as these subs are relatively low profile, they don't interfere with the seat movement here.

So, here goes...

First I removed the subwoofers from their housing that they came in:
ImageUploadedByTapatalk1415040425.173711.jpg

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Next, I made a template from masking tape of the magnet part of the speaker, which I would be counter-sinking into the back wall. I then offered up the subwoofer to the back wall, and placed the template in the correct position:
ImageUploadedByTapatalk1415040572.411478.jpg

ImageUploadedByTapatalk1415040624.222592.jpg


Then, I took a sharp knife, and cut around the template, through the carpet and foam (varies in depth about 1-2cm) and removed the foam:
ImageUploadedByTapatalk1415040846.301175.jpg


If you decide to attempt this modification KEEP THE CIRCLE CUTOUTS IN A SAFE PLACE, should you wish to return to a factory setup!

All that was left to do was run the wiring from the back of the headunit, down under the centre console (mine was already removed as part of my refurbishment) and out of the cut-outs that were just made. As I mentioned before, I spliced into rear speaker wiring at the headunit, then I found the best path for the wiring was down the middle of the centre console, going under the carpet where the carpet has been cut out for the ashtray, and then all the way under the floor carpet and out of the circle cutouts that I made for the subwoofers.

It was then simply a case of connecting up the speakers, and fixing them in place with some 1" long screws, with quite a deep thread for grip. As a precaution (although not necessary), I also used a couple of slip nuts on the top two screws of each subwoofer to strengthen the screws' hold, which I inserted under the carpet through a small incision I made next to the screw holes:
ImageUploadedByTapatalk1415042000.232291.jpg

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Et Voila! All completed in under 1 hour of install time (once the seats and centre console were out!), and for £25 total cost, I am dead happy with the result!

ImageUploadedByTapatalk1415041666.644780.jpg


Hope you enjoyed reading this, any questions please feel free to ask!

David
 

hard top

Zorg Expert (I)
Dutch Zeds
The M44 Massive
Joined
Dec 5, 2011
Points
213
Location
Netherlands
Cool, how far do they stick out, looks quit a way in the pic?
 

GazHyde

Administrator
Administrator
Global Moderator
M Power
Joined
Dec 2, 2011
Points
226
Location
Berkshire
Model of Z
Z4 MR
They look good, so will be interesting how they sound. Depth wise wouldn't cause me any issues, as I've got short legs so my seat is always forwards!
 

paranorz

Newbie
Joined
Nov 1, 2023
Points
3
What connections were on the subs? Im looking at a pair on ebay and they seem to have some kind of connections box, rather than speaker terminals?
 
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