Author Topic: Upgrade stereo wiring (Read 6385 times)

P. Kennedy · « **on:** October 05, 2007, 11:29:04 PM »

When I bought this car in late July, it had an aftermarket Pioneer head unit powering the 4 factory speakers. Sounds absolutely terrible. The Pioneer unit is a DEH-3400 from 2002 and has a fair amount of power for a head unit, so I think it's salvageable. Maybe doesn't have the capability for updating. Don't know.

My current challenge is understanding the BMW factory common ground wiring (if I am referring to it correctly) and how I might go about upgrading the wiring for newer equipment. I know I need to run all new wiring, but I don't understand how to go about it. I just replaced the rear speakers with Boston Acoustic 5.25's, and still using the factory wiring, they sound even worse than the factory 5.25's. I have some JL Audio components coming for the front, but I need help figuring out how to upgrade the wiring, if in fact it is possible.

Anyone willing and able to help me learn? I looked over posts containing color coded wiring references, and am grateful for that. Any an all help greatly appreciated.

ak96ss · « **Reply #1 on:** October 06, 2007, 07:23:40 AM »

The easiest thing to do is to just replace the speaker wiring entirely - well, maybe not the easiest, but the best, I would say.

You can abandon the existing speaker wiring in place, just leave it disconnected, and run all new wire to your speakers. If you are running amps in the trunk, you'll need to run RCA cables back there from the head unit. Otherwise, you'll just need to run new speaker wire from the head unit to each of the speaker locations. Don't run any speaker wire along the passenger side sill, that is where the battery cable is so you'll pick up some noise if you do.

Fish your new wire from behind the head unit across the steering column area, and down the driver's door sill - there is a nice cavity there that has factory wire running in it that provides plenty of room for speaker wire.

As far as the connector for the head unit, is it not already hooked up? I'm not sure I understand why you would need a new connector there.

christophbmw · « **Reply #2 on:** October 06, 2007, 11:41:10 AM »

Quote from: ak96ss;35118

Don't run any speaker wire along the passenger side sill, that is where the battery cable is so you'll pick up some noise if you do.

that only applies to RCA cables, speaker wire doesnt usaully pick up any noise, im running a 1400 watt stereo W/ the front right speaker wire through the passenger sill and found no noise difference then if it where down the drivers side (i wanted to use equal length speaker wire for all speakers so i tested it and found no noise pickup). RCA's will pick up tons of noise if they are within 10" of the power source (or any speaker). just my 2 cents.

sha1234 · « **Reply #3 on:** October 06, 2007, 01:38:24 PM »

i had a big problem when i started in my audio journey with faulty ground etc... i replaced all stereo wires... new power 12 constant and ignition new grounds... and nice 14 gauge wires to all speakers... and it still sounded... meh... when i upgraded to a 4 channel since there is all the ability to tune then it really sounded good...
comps wont sound anybetter if they are just running of the deck... they are meant to be amped so you can really tune them...

overall spend money to upgrade everything in the audio... orelse certain things with out shine others... like a nice sub with shit speaekers wont sound good... or if since htey are all 5.25 speakers you bass range wont be great so go for a 10 or something...

P. Kennedy · « **Reply #4 on:** October 06, 2007, 03:17:49 PM »

Thanks for your responses. I should have mentioned I will be using an amp and a subwoofer in the boot as well. I wasn't sure at first HOW to replace all the wiring (though I am fully prepared to do so) but now I have a better idea. Should be fun project.

P. Kennedy · « **Reply #5 on:** October 07, 2007, 09:11:14 PM »

At the risk of kicking a dead horse, can someone explain to me the differences between the BMW common ground wiring and the wiring I need to update to? The speaker wires are merely Left, Right, Positive & Negative combinations, yes? So then it must be something in the +12v or chassis grounding? Please help me to learn.

Thanks,
Pat

P. Kennedy · « **Reply #6 on:** October 08, 2007, 10:48:57 AM »

bump - o - rama

gearheadE30 · « **Reply #7 on:** October 08, 2007, 02:57:39 PM »

I'm planning on upgrading my stereo as well, so I also await an answer.

BTW I currently have an Alpine CDM-7874 hooked up to the stock premium audio. It toesn't sound bad, but there is no bass and clarity is a bit lacking. I founed a good price on a set of Kenwood KFC P507 speakers and tweeters, so I'll put those in the doors and kick panels. Any suggestions?

P. Kennedy · « **Reply #8 on:** October 08, 2007, 03:10:00 PM »

My only suggestion would be the obvious: Subwoofer. I am adapting one even though I don't have the pass through rear seat back. Plus I am cutting and fitting 6.5" components either in the kick panels or the doors. Might make some custom pods. Did that on a 944 Turbo S once upon a time, turned out great.

ak96ss · « **Reply #9 on:** October 08, 2007, 03:23:50 PM »

If someone would be so kind as to make fiberglass enclosures for 6.5" components that fit in the dead space between the back seat armrest panel and the outside of the car, I would be most grateful...

I honestly don't know for sure what the difference is between the way the stock BMW radio is wired and how 'regular' radios are wired, mostly because I'm not sure how a 'regular' system is wired. The stock radios look like they all come to a common ground in the headunit itself, and ground to the chassis. I'm guessing, then, that 'regular' radios do not do that, but I have no real clue.

I just wanted to lose the puny wiring that came with the radio and put some larger gauge cable in - it's overkill, I'm sure, but it works.

P. Kennedy · « **Reply #10 on:** October 08, 2007, 04:12:28 PM »

Quote from: ak96ss;35250

If someone would be so kind as to make fiberglass enclosures for 6.5" components that fit in the dead space between the back seat armrest panel and the outside of the car, I would be most grateful...

Have you looked at: Q Logic ?

ak96ss · « **Reply #11 on:** October 08, 2007, 04:43:05 PM »

Their application guide only goes back to '93.

EDIT: Not to mention their applications all seem to be for the footwell.

FL318i · « **Reply #12 on:** October 08, 2007, 05:02:45 PM »

i will love to help since this is my grounds but i don see what the big problem is?? i mean if u wanna run all new wires then whats the biggie??

speaker wires are easy,even easier since you are running an amp just make sure that u check for the right length of the power wire from the battery to the amp according to the gauge i know you probably think that because the battery is right there and for clean look purpose a short wire will be great but that is not the case, constant power ignition and ground i dont see a need for upgrading this, my advice will be to go to a book store and buy a book it will teach you a lot and u will make a better job at the end.

P. Kennedy · « **Reply #13 on:** October 08, 2007, 10:00:04 PM »

Thanks for your advice. It's only a "biggie" because it's not my "grounds" as it apparently is yours. If I had all the answers, I wouldn't be asking for help on this forum.

Typical speaker wire is 16 ga., yes? Why are all the wires in the adaptor so much smaller, like 22 ga. or whatever they are. Is it disadvantageous to interconnect those two different gauge sizes?

FL318i · « **Reply #14 on:** October 08, 2007, 11:15:46 PM »

Quote from: P. Kennedy;35269

Thanks for your advice. It's only a "biggie" because it's not my "grounds" as it apparently is yours. If I had all the answers, I wouldn't be asking for help on this forum.

just wanted to help, i dont need your sarcasm!!!, i wasnt trying to be a smart ass but anyways good luck i hope you figure it out