E60: Unbearable rattle with new Alpine install + shonky fix.

No sooner have I got the Alpine install sounding heavy in the E60, it shakes some trim loose and begins to cause the world's most annoying rattle. At first it was barely audible and only at high volume. Now it's all the time and louder than ever, all music and even low volume. 

It turned about to be the plastic trim-panel behind the centre arm-rest. I've stuck some foam-sponge into the gaps around it for now and hopefully this will help, but it will need something more like Dynamat at some point.

The low-end rumble produced by the E60s stock-subs, amplified again through the Alpines is shaking panels loose on a very well built car. There is a 22mm thick carpeted MDF panel behind the rear-seats that forms the back of the boot and the front-facing subs are driving straight into it, which already muffles the bass considerably and gives vibration in the cabin. I have read posts where large holes are cut into the MDF in front of each sub to get the bass through, but I can't see that helping vibration and and am reluctant to cut the panel yet. Turning the subs to face away from the rear-seats might help the vibration but I doubt it'll make the bass sound any cleaner and am loathe to expose the sub-cones to loose luggage and lose space by bringing the amp / x-over out onto the boot floor. Again, some sort of sound-matting such as Dynamat will need fitting around the boot and between the rear-seats and parcel-shelf to iron out the remaining hum. As for getting more bass through, the best quick advice would be to open or remove the 'ski-hatch' if your E60 has one, sadly mine does not.

The optimal settings I've got so far since taking RCA-feed from the stock-subs is to have the iDrive bass set to +3 or 4 and the X-over on less than a quarter gain, as the low-end frequencies are just so loud on the Alpines. The low-mid frequencies don't really get to the subs at all though and this where the stock-system needs to take over, but turning the bass over halfway on the iDrive is over-driving the subs and there's no choice but to keep turning down the x-over gain. Hopefully I can turn the x-over back up a bit again now the rattle is sorted.

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.

E60 Audio: RCA Feed from Rear Speakers - quick n dirty guide.

**Caution: This guide is for fitting extra component/coaxial speakers and is NOT suitable for fitting subs as the rear-speakers receive no low-end frequencies. If you are fitting subs then see THIS GUIDE on getting bass-RCA from the stock-subs.

This guide covers a very quick and easy way to get an RCA-feed into the boot on your BMW E60 and other iDrive models. This method is only suitable if you are fitting extra component or coaxial speakers [inc. 6x9s etc.] where the range of frequencies handled by the rear speaker-EQ are required.

PROCESS:

** If you are fitting extra component/coaxial speakers then adding a crossover-box to the RCA-feed before the amp should not be necessary. If you intend to use a crossover, substitute the 4 wires of the Red/White RCA-cable in this guide for 4 lengths of normal wire and see THIS GUIDE on how to install it.

1. Take a normal Red/White stereo RCA-cable, cut both plugs off from one end and separate the two wires down most of its length. An RCA-cable of about 4 feet should be plenty to reach up to both rear-speakers.

2. Carefully unwind the earth-wire from around each coated-wire and twist them off, so each of the coaxial RCA-wires is now split into two, as shown.

3. Bend each of the four wires over about 5mm from the end and completely sheathe the two bare earth-wires up to here, so they are well separated from the red/white live wires, as shown.

4. Gently prise off each rear-speaker grille using a flathead screwdriver, starting at the front edge.

5. Remove the 3 screws holding each rear-speaker using a T20 Torx-head wrench/driver, then lift out and unplug both speakers.

6. From inside the boot, light can be seen coming in through the empty speaker-recesses. Route one cut end of the RCA-cable up into each speaker-recess. They should easily be reached now from the parcel-shelf.

7. Splice the coated live-wire of the RCA-cable to the + speaker-wire on each side and the bare earth-wire to the - speaker-wires. The colours are as follows:

O/S - Yellow/Black +, Yellow/Brown -.
N/S - Black/Red +, Black/Purple -.

8. Push the wires down into the parcel-shelf and replace the speakers/grilles.

Done in 5 minutes!

E60 Audio: TSK TD-22 Speaker Level Converter (X-Over) - How to fit.

If you're running an external amp using the audio feed from your rear speakers then you will be getting the full range of frequencies through your subs. An after-market head-unit with an RCA output, or some amps, will have a x-over built in that can be set to only allow bass frequencies through. If your amp doesn't have one and you don't want the subs to sound awful with your BMW's stock system, an external x-over block is what you need.

In my case, the Alpine V12 1kW amp I'm now using has no Gain (volume) control either, so the addition of a x-over means I can turn down the booming subs without affecting bass going to the stock speakers. The cheaper Toxic 1kW amp I was using in the E39 had both gain control and a built-in x-over, so I could run the subs in balance with my system. Sadly, the 4-chan Toxic amp was never loud enough and any attempt to turn it up would cause the car's whole sound system to trip-out, which I cover in this post, and this really doesn't work in an E60 so it's high time I got around to sorting the matched Alpine amp.

X-over blocks used to be large, expensive things used only by pro's and had more controls than the head-unit itself. Now however, there are loads of smaller blocks available, many designed just to convert a speaker-feed into low-freq RCA. I went for the most popular unit amongst the BMW forum guys, a T.S.K TD-22. Not sure if they're all made by one supplier, but these same looking kits can be bought almost anywhere - I got mine off eBay of course, a snip at £5.95 delivered. 

The instructions are a little vague to say the least and mainly in Chinese and broken English, I have written them out in THIS POST on Panabloga, but here is a better version:

Red: 12v Switched - The x-over needs its own power that turns off with the ignition.

Blue: Remote on/off - Tells the x-over to turn on only when the amp is powered up.

Black: Ground - Connect to earth.

Grey: Right speaker + wire.

Grey / Black: Right speaker - wire.

White: Left speaker + wire.

White / Black: Left speaker - wire.

I joined the red and blue wires together and crimped them both into the amp remote wire coming from the cigar lighter, which is 12v anyway. I cover fitting that in THIS POST. I extended the Ground wire and earthed it to the same place on the body as the amp, rather than into the GND socket on the amp itself as suggested. The speaker wires are pretty short and the only place a +/- audio-feed can be drawn from is where the wires go to the speakers themselves at either side of the parcel-shelf, so I extended both of these into the boot and mounted the x-over block next to the amp on the sub-box.