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.