Subject: E34 audio upgrades Author: rick540 : member since April, 2007 : 1055 posts Posted on: 2008-03-02 17:55:25

Just finished this one, took me months literally.

Heres a few points to note if it could help anyone, as The E34 I have found to be one of the worst cars I have ever tried to set up a decent sound system in, even though I finally got it sounding great. I used to fit car audio for a living, but still the E34 had enough quirks to give me a serious run for my money (resonances, soundproofing between trunk and cabin etc)

I have the Becker setup with the alpine 10 ch amp "Bavaria C RDS" which I decided to not replace as it is an excellent unit with a nice integrated retro BMW look, but these upgrades should apply to all.

I replaced the stock miniscule low freq 5" speakers with high power 250w aftermarket polypropelene 5" woofers. (bolt in). I also added a 12" compact subwoofer tube to the trunk, firing to the side.

Then an aftermarket four channel amp was fitted + an additional monoblock for the sub (both of these fitted nicely below the rear trunk mat in that wierd cavity above the fuel tank)was nice and neat, and cannot be seen. Wiring is fairly straght forward and I added wiring to the existing loom, including 2 guage power from the battery.

The factory amp/active crossover was kept, powering the mids and tweeters front and back as I didn't want to mess with this, and that part is already set up properly by BMW.

Tapping the L/R channel was a real pain on this setup, I modified the input plug to the factory amp and tapped the two channels (using a powered high to low converter device 2ch in 4ch out) and fed the output to the two new amps.

To my dismay the system sounded awfull no matter what I did. After endless messing with the thing and using audio SPL diagnostic equipment I have, I tuned the sub filter to work only below 75/80Hz basically subsonic frequencies but at very high power, and this made a world of difference. Every car chassis is unique in the way you would tune a sound setup, Each transmits and absorbs sound around the car in different ways, and the interior trim has a profound effect on audio frequencies.

For the first time ever I found one car that likes just the really low frequencies......

Anything above 80Hz with the E34 and the chassis just seems to transmit an awfull amout of noise from the sub in the trunk and not any real base, messing up the sound stage. This probably has something to do with some materials used for the interior/chassis having resonant frequencies at or above 80Hz, or multiples of frequencies between 80 and 180Hz

Anyway the bottom line is to get decent base in an E34, tune the subwoofer to play only the really low inaudiable frequencies at very high power, and only then does it sound OK. The higher base notes travel from the sub through the car way to easy and really mess things up. This one was particularly unusual which is why I'm mentioning it.

1994 E34 540iA M60 Glacier Blue
1997 E39 540iA M62 Aspen Silver

(:2 X 540i, dreaming of an eight litre V16 BMW :)

Capetown South Africa
"The Mother City"

• E34 audio upgrades - rick540 2008-03-02 17:55:25 (216 views)
  • Re: E34 audio upgrades - Joe Manieri 2008-03-03 15:53:00 (98 views)
    • Re: E34 audio upgrades (url) - eastcoast5 2008-03-26 09:36:01 (41 views)
    • I'd second that as the EU spec ( Aust.) I have does not appear - BMW-Test-Pilot 2008-03-03 20:38:36 (83 views)
  • Boy oh boy a Lincoln Toy - what a lot of effort. and Thanks. (nt) - BMW-Test-Pilot 2008-03-03 06:17:58 (73 views)
    • I think MB-Quart make direct drop in upgrade speakers (nt) - rick540 2008-03-04 02:38:07 (71 views)