E34 stock stereo and subs??

[bmw_525i]

I have a 90 525i with a stock head unit and was wondering if i could hook a sub up to it with out changing the head unit bc the stock black goes so well with my interior and i hate the tacky aftermarket ones. I do have upgraded speakers idk if that matters or not. I'm not really experienced in sound systems so any help would be greatly appreciated

[Tiger]

Yes, it can be done. What you need on the sub is line input or use an adapter... splice the channel frm the amp using the speaker wire that sends the signal from head unit to amp.

[bmw_525i]

ok what do u mean line input or adapter and would a different amp make this situation better or worse??

[Tiger]

Usually an amplifier uses RCA cable for the music signal. Some amplifier has both speaker wire input and RCA... we are looking for the speaker wire input. If you don't have speaker wire input, then you need speaker wire to RCA adapter.

Basically the head unit put out speaker signal to the factory BMW amp... and BMW amp then amplify more and crossover to 10 speakers in the car. That is the wire we want to splice into to feed into the amp... the one from head unit into the bmw amp.

[bmw_525i]

I found this website and was wondering if this is basically what ur saying. plus it has pictures lol. If so do this mean i have to run two amps like this website is showing? sorry for all the questions but I have never done anything like this before. I really appreciate it thanks

[Tiger]

URL please?

[tim eh?]

You should be able to do this with just an amp for the subwoofer.

I don't want to say for sure it will work because the e34 shares grounds and it might mess up the front/back fading, but it should work.

You just need to steal a signal from the wires going to the factory amp, like tiger says. The signal you steal will go to the sub amp.

Your sub amp needs a Left and Right signal. Each of these is on a circuit and needs the signal to return via a ground. The amp uses RCA cables which have two wires in them, the signal wire and the ground wire.

You can take an RCA cable and cut one end. The outer braided wire is the ground and the wire in the middle is the signal wire. You want to connect these to the appropriate wires going to the factory amp. Use this plug layout to find them...

http://www.bimmernut.com/forum/attachment.php?attachmentid=6668&d=1238668311

The appropriate wires are the ones in the 'input' box. See how there are only two shared grounds (L- and R-) with the four signal wires. I would suggest using the rear signal (RL+ and RR+). Do these splices... Left RCA -> inside to RL+, outside to L- ... Right RCA -> inside to RR+, outside to R-. Make sure the original connection to the factory amp remains intact!

[bmw_525i]

Sorry i meant to put it in there but forgot lol http://www.bmwe34.net/E34main/Upgrade/Stereo_subwoofer.htm

[lilcallaway]

Sorry i meant to put it in there but forgot lol http://www.bmwe34.net/E34main/Upgrade/Stereo_subwoofer.htm

Yep! Pic #5 is the best way when using factory HU

[Tiger]

Yep, that is the way to do it.

[bmw_525i]

Alright thanks guys