Upgrading 'Premium' Sound System

[Tkearns7]

I have a '91 325iX, which comes with a Premium Sound System. That just means it has a shitty factory amp in the trunk to increase its power. I was wondering if anyone who has a premium sound system, and has upgraded their headunit, can help me out.
I just bought a Panasonic headunit, but i ran into several complications when installing it. The main problem is bc of the amp. I disconnected it, as recommended on many sites. However, I need to know a way to bypass the power. Since the power comes from factory headunit, then goes to amp, then goes to speakers. Has anyone installed a aftermarket headunit and had to deal with the amp. I'm really looking for a way to bypass the amp, or if it is good to just leave the amp. Appreciate the help.

 

[mrferg]

I bought my car and it had an upgraded headunit with the amp. I have no clue how exactly it was wired, and in my opinion it sounded awful. So I ripped out the amp and rewired the whole car. It sounds alot better then using the stock amp. Sorry I'm not of much help.

 

[equate]

I went through all of this. Save your sell 999 hassles and run new wires to all the speakers. You lose so much quality with the very small wires that are stock and if you bypass the amp you have a lot of unnessicary wire. It goes form the HU to the back for the amp then back to the front for front speakers. And it changes from like 22ga. to 24ga. Running the wires is very simple to do proabbly about 30 min of work and it will sound and perform better.

 

[Tkearns7]

I dunno a lot about sound systems. i'm able to replace the stock wiring harness?

 

[jrt67ss350]

Yeah, I agree with equate. I don't have the premium sound system (only a 325e) but I have an Alpine head unit and Polk rear speakers that were in the car when I bought it. Whoever installed the stereo ran new, larger gauge wiring to all of the speakers. I think that's the way to go in these cars, especially since the stock stereo wiring is very complicated and small gauge wiring.

 

[Tkearns7]

thanks for the help

 

[equate]

I don't think there is a wiring harness for you. If your going to use the stock wire you will have to cut the fader switch apart, then BMW thought it would be a good idea to use a commen grounf for 1/2 the car and its just compleate BS from there. There is an ignition wire and a constant 12v. I forget which one they are but if you look on the back of your stock deck its gonna be one of the ones on there thats not the speakers. Use a voltage meter to find which is which

 

[xLibelle]

as a audio installation guru back in the day, i had seen many a car that had these shitty preamps...
they all seem to use a common ground. its not all that bad to wire it up the way its meant to be, once you figure out the wiring, but youre better off (quality wise as well) by just running new cables. (note, guage is not a factor considering what bmw already has installed, just go with the best when you do everything from scratch)
one thing you need to pay attention to is the dimmer cables, as they run in series through the HU usually, otherwise the obc is next in line to look bad.

(word of advice for if you install an amp and its in the trunk - its in your best interest to keet the rca cables away from the alternator lines!)

 

[Rukus]

If you want decent sound in any car. TOTALLY ditch factory ANYTHING. speakers, amp, deck wires .. etc.

If youa re just looking for a cd player and sound, i say Pick up a decent head unit, and replace the factory speakers with that car stereo shops call "factory replacements" run your own speaker wire, and if possible get an adapter harness for the cd player plug, or just simply run your own wires for your deck. find out which wire comes from the ignition (that used to turn your factory on) and splice into that. Run a constant power straight from battery, and for the ground wire , ground it to anywhere in the car. bang. 3 wires plus 8 speaker wire connections to the deck (4 speakers, 1 wire each with pos/neg ) and bam you are done!

Simple!!

If you want something more, its the same idea, but then you got options such as do i want a subwoofer? maybe i want more out of my speakers? (run your speakers from an amplifier) well if you wanna go that far, i am sure any car stereo shop will help you with your options. If you ahve any direct questions for me, just ask.

 

[Tkearns7]

Just one more question. I was able to install the headunit, but only connected it to the front speakers (for now). The rear ones are a little more difficult to get to, so I'll have to find out exactly how to do that. But I noticed that the front speakers are low in volume. In fact, I think they're even much lower with the aftermarket headunit (50Wx4). I'm not sure if it's a bad connection somewhere, altho im confident I wired everything correctly. Also, the speakers produce very terrible bass. It's so bad, I have to elimate bass period. I heard things about an integrated fader, but im not really sure what that is. is this typical of factory speakers? I'm thinking of just replacing them as well, athlo i'd prefer saving the money.

 

[Tkearns7]

Also, I replaced the factory speaker wiring with 16ga. wiring.

 

[mjbst111]

my premium speakers sound quite amazing. i would never replace them. They even have very decent bass, although i did ad subs to help them out. but the treble is very crisp and clean. and the speakers produce pretty decent sounding bass, i mean they aren't subs and don't get very loud but for thier size they sound good.

when i rewired my speekers i do remember having to change the tweeter wiring so they were connected to the frond speakers near the floor then wiring the speakers on the floor to the head unit. did you wire yours similarly? Look at how the rear speaker tweeters are wired to the "subs/midrange" and do the same with your front tweeters, "subs/midrange"

maybe that will help. hope so.

 

[epj3]

Mine has a sony head unit wired directly to the speakers (ie no amp) and it sounds pretty good.

 

[Rukus]

Do those tweeters have crossovers on them? Where are the crossovers for those tweeters located?

 

[mjbst111]

i think they are on the back of them.

 

[Tkearns7]

the rear speakers sound great. but something is going on with the front speakers. To start off, the tweeters don't work. That's prolly whey theyre not sounding so great. I guess I'll have to rewire the connection between front tweeter and front speaker. it kinda looks frustrating to remove the door trim etc.

and the front speakers are set up differently from the rear. The tweeter is connected by one wire instead of two. I guess the pos. and neg runs off that one wire.

 

[mjbst111]

You don't have to take anything off the door except for the little plastic part the speaker is in. just pull it off carefully. once you get that off just note the colors of the wires and find them at the harness that goes to the door from the interior. one of them should go to the speaker and the other one to the amp or old head unit as far as i remember

and the front speakers are set up differently from the rear. The tweeter is connected by one wire instead of two. I guess the pos. and neg runs off that one wire.

i did say they are wired differently, there are two wires, just cut the one that goes to the amp or old radio and wire it to the other speaker like the ones in the back

 

[bichmgnt]

The front speakers have a crossover built into the wiring for the door mounted tweeters. You may not have wired the speaker's to your head unit correctly if the tweeters aren't working and the speakers sound bad. Make sure you get the positive and negative correct on both speakers or your bass will cancel out.

When I upgraded to a new stereo I replaced all four speakers and installed Infinity 505cs component speakers. To put the tweeters on the door I used a dremel tool to get the old tweeter out and replaced it directly with the new tweeters. They epoxied right in and looks completely stock. I used the old wiring to go to the tweeters because they don't carry much power (the only reason to have bigger wire) and because it was so much easier!

The sound is amazing. Of course the Rockford Fosgate amp in the trunk doesn't hurt either.

Steve