Saturday, 15 March 2014

E60 Audio: Getting a Bass RCA (Audio) feed from the Stock-Subs.

If you want an aftermarket amp + subs in the boot then you need an RCA-feed and tapping into the rear speaker-wires does not work on the E60 and other iDrive BMWs as it does on the E39, E46 etc. All US E60s and others with factory-upgraded sound-systems have two subs under the front seats run by a stock-amp in the boot, on the left-hand suspension turret behind the panel. If you have this see this guide on //// to tap into the wires on the stock-amp.

Most non-US cars don't have a built-in amplifier in the boot, but they still have subwoofers under the front seats. These are driven by the head-unit and the EQ sends a different set of frequencies to each set of speakers. [See: http://musicarnw.com/bmw-factory-audio-explained/]. The rear speakers are only 4" so they don't get much low-end at all. To get proper bass it's worth going the extra mile and running cables all the way to the stock-subs, which get the real low-range frequencies.

** NB: This is to fit subwoofers on a bass-only channel. If you are fitting component speakers or 6x9s then you will need a broader range of frequencies and are better to tap the rear speaker-wires, covered in THIS POST, which is a lot easier. **

PROCESS:

Getting to the sub-wires is quite involved, but not difficult if you have the right tools. There is a + and - wire to each sub, so two new speaker-wires will need running either side. I used one length of twin-core 1.5mm wire on each sub, about 6 feet of wire is plenty.

1. Slide the seat all the way back and remove the plastic caps from the front of the runners.

2. Remove the two bolts from the front of the runners using a T50 Torx-head wrench.

3. Slide the seat all the way forward and remove the two bolts holding the rear of the runners using a T50 Torx-head wrench.

4. Lift the seat up. tilt it back out of the way and prop it up.

5. Remove the four crosshead screws from the plastic-grille above the sub and lift it off.

6. Move the carpet on the door-sill out of the way and cut the fabric-tape binding the wires going to the sub together so they can be pulled apart.

7. Splice your new speaker-wires into the wires going to the sub as pictured below. O/S - Red/Blue for [+] and White/Brown for [-]. N/S - Red/White [+] and Brown/Yellow [-]. [Soldering would be the best way, but I just went for the quick and easy Scotch-lock way again].


8. Run the new speaker-wires out from under the carpet and
along underneath the door-sill trim, up the side of the back seat and along the top of the back seat to the middle.

9. Lower the centre arm-rest and remove the plastic-trim panel from behind it by pulling out the two push-clips from the lower edge and working it off.

10. Thread the new speaker-wires down behind the back-seat at the centre. Be sure to thread the wires just behind the seat-back, but not down against the parcel-shelf, which ends at an annoying ledge. If you see the wire passing down behind the small round hole near the top of the seat-back behind the arm-rest then your on the right route.

11. Inside the boot the new speaker-wires should be seen poking down into the boot, or if it isn't you should be able to reach under the lip at the back of the boot and pull it down.

12. Install the four wires to your amplifier either directly by adding red/white RCA-type connectors to them, or via a crossover-box, which is the better method. Fitting a crossover is covered in THIS POST.

11 comments:

  1. Hi! Does it matter If you wire only one side? Has it difference if it got Wired each side?

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    1. Technically no, you can wire one side up to one amp channel for mono, or split one side to both RCA channels and it will work fine. I would imagine there is still a stereo image sent to the floor-subs, so you would lose out on anything sent to the unused side of the car. If you wire one sub to both RCA-channels then the sound signal will also be split two-ways and degrade a bit to be audio-pedantic!

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  2. I need help i have everything connected and i have wired from one side from the sub under the seat to my converter and my subwoofer does not work

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    1. Do you have a remote ON signal to your amp? Check through the whole guide and troubleshoot. Provided you have wired your RCA from your stock-sub correctly there is no reason a signal shouldn't be coming through.

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    2. https://www.beemerlab.org/p/e60-audio-wiring-ampsubs-into-standard.html

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  3. I have everything correctly done and remote is working propely, and i have puted my converter cable to the amplifier in the back to the subs under the seat and the subwoofer does not work

    ReplyDelete
    Replies
    1. Right, lets get into it... not telling you how to suck eggs mate because if you have attempted this then you clearly know what you're up to, so... when you say 'converter' are you referring to a crossover/X-over unit?

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    2. As in the guide, your amp should have red power and black earth, the two signal (RCA) cables usually red/white and a remote signal to the amp. The subs under the front seat are receiving the signal from your head-unit and then piggy-backing that to your amp, which is then sending that to your aftermarket subs. What subs / amp are you using? Can you post a photo to imgur or somewhere? Thanks

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  4. Does it work on the bmw 530d e61 2005 beacuse its the same cables from the subs under the seat

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    Replies
    1. Yes, E61 is exactly same wiring, though perhaps your Touring has a trunk-mounted additional sub/amp behind a panel? Not sure from memory if they have this option but if it did then that would be a better place to draw signal from than under the front seats. Is yours an LCI model? I have not fitted subs to an LCI (not that I know of anyway!) and wiring setup is different, but the signal to the floor-subs is going to be analog anyway, so should be fine for running any additional analog sound systems off of it!

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    2. My girl's brother got a 2007 late-model E60 with all the trimmings and we fitted subs to this with no problems at all, though don't think it is an LCI model. Pretty sure have done this to a 2005 E60 at some point too. Hmm, definitely something amiss.

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