More Info On Sound System Upgrades... (archive)

Folks:
I have been investigating this sound upgrade thing for months. Now that I actually have my car I have had a chance to look things over and speak with a few installers. All of these comments pertain to the standard sound system, not the DSP unit.

The installer I spoke with today recommends replacing the factory amp to drive the factory speakers, plus adding a subwoofer. He has an E34 that he did this to and let me listen to it. The increased power definitely cleaned up the sound and the speakers could handle the 40w from the a/d/s/ P640. He chose an 8" a/d/s/ sub in a custom box firing through the ski-sack pass-through on his car. The sub was a little weak for my taste, but the rest sounded pretty nice. It was actually a little heavy on the high frequencies, but that could be because of the weak sub.

Replacing the amp in the trunk is an easy task on the E39. I foresee one MAJOR problem with this setup however: calculating and adjusting the crossover points for the factory speakers. The guy I spoke with wired his like this...

40w to each front channel (tweet+mid+woof=1 channel)
40w to each rear channel (tweet+mid/woof=1 channel)
40w to sub (he has a dual voice coil sub, so it's got 2 separate stereo channels wired to it)
Total of 6 channels on the P640 amp

I do not know how he did the wiring to string the tweet+mid+woof onto one amp channel. In the E39 each speaker has it's own separate channel and the amp internally crosses them over. This raises another huge question. How do the 3 individual speakers get crossed over in this setup? He didn't mention adding any crossovers. Maybe the E34 does have external crossovers, but I know the E39 does not.

So, I just wanted to share this information because I have not heard of anyone just replacing the amp. I'm hoping Bob Hazelwood will read this and have some comments (The guy I spoke with knew you) on the difficulties associated with calibrating this setup. I know you already commented on your setup and the approximate crossover frequencies used. I'd like to find out how to actually do this calibration and give this proposed setup a try. I'd hate to drop my car off and pick it up at the end of the day with the work completed. I get serious satisfaction doing this stuff myself and knowing how to tweak it is very important to me.

Thanks!

Jeff
'99 528i Sport

Follow Ups:

ADS speaker comparison Dao Hoang 10:34 6/05/99 (0)
Re: More Info On Sound System Upgrades... Willard 21:29 6/04/99 (2)
- Re: More Info On Sound System Upgrades... jvr 11:38 6/05/99 (1)
  - Re: More Info On Sound System Upgrades... Willard 15:04 6/05/99 (0)

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