Re: The Sucking Sound of BMWs (long)

[Bob Hazelwood <woodyh@xxxxxxxxxxxxx>]

Hi folks;

I've read the various responses to Steve Foster's post about BMW radios sucking with
great interest. This is because I am both an audiophile and a Bimmerphile. I was also
the designer of the premium audio system installed in the Range Rover County SE and
County LWB models from MY1991-1994 (USA only), which was pretty well reviewed in the
press. Since I am employed in the industry, I responded privately to Steve so I would
not be accused of Digest advertising. However since there seems to be quite a bit of
interest in this subject I'll post here and try to keep the brand pimping down.
Hopefully I can contribute some useful content.
I won't get into the discussion of how important a better sound system is in the
first place. If you don't care you have probably already paged down. I figure if
you've read this far you're at least mildly interested .
My personal-ownership BMW experience is with a 1987 E30 and my current car, a '93
E34. However I have been involved with installations in one form or another with
almost all models exept the current 7-series. Like many of you, I am no longer a kid,
so I will not compromise the utility or appearance of the vehicle for the sake of a
stereo. I also wont throw off handling balance to put in a 50 pound subwoofer
enclosure. Also, since this is my business, I may be able to call upon a few
resources that are not available to the general public. So, this is what I have
found.
All of the current BMW systems actually have pretty good radios/CD players. Not the
best, but pretty good. Thet really measure about as well on the bench as most
anything available short of absolute top-of the line aftermarket units. The
improvement which some people note when replacing the radio has more to do with the
fact that the BMW radio is equalized to supposedly make up for inadequacies in the
factory speakers, where an aftermarket radio is not. The low frequency boost in the
factory radio seems to just make the speakers distort easier and not really sound
better. Therfore you are hearing a different frequency response with the aftermarket
radio which will sound better to many people. This is a viable option forZ-3 (E?) E36
and E34 owners, but is less viable for E39 and E46 due to the new format. Replacing
the speakers and amp can work wonders though, even with the factory radio. The
architecture of the BMW system actually makes this easier than with most cars. In
current BMW's, the amplifier contains a built-in crossover for the speakers. This
means that each pair of speaker wires is already run from the speaker location back
to a common point in the trunk. It's incredibly convenient! I've installed a two-amp,
10-channel system in my E34, and didn't have to run any signal wires at all! I only
had to run two 12V power wires about 6 feet for the new amps from the battery. The
whole installation only took a Sam Adams six-pack  (I estimate an equivalent PEE
rating to a half-case of the reference-standard pony bottles.) In most cars this
would have been a two-case (RR) minimum. However, on the flip-side, BMW's practice of
incorporating the crossover in the amp means that if you replace the speakers, you
pretty much have to replace the amp and vice versa. This is because the BMW amp's
crossover is highly unlikely to be appropriately matched to replacement speakers.
Using the factory radio with upgraded amps and speakers can be very rewarding, and if
done right requires no irreversable vehicle changes.
One other approach which works well is to simply add a subwoofer and subwoofer amp to
the factory system. This won't make the edgy high's any smoother, but it takes away
that annoyingly distorted bass which make Tympani sound like Whoopee Cushions. You
can easily get the signal from the factory wiring between the radio and the factory
amp to drive the subwoofer. Personally I'm using a 10" subwoofer mounted behind the
pull-down armrest with no enclosure. It works well and takes up virtually no trunk
space. It's a little more difficult with fold-down seats, but not impossible. Powered
Bazooka tube type woofers can work well here also.
Contrary to popular belief, the current BMW factory radios have relatively standard
output level and common grounding which can be plugged directly in to most modern
power amps without needing any special adaptors, except to change the plug from the
proprietary BMW connector. (This only applies to some, not all, E28 and E30 radios!)
We have a few suggestions posted on our web-site which may give those of you who are
interested some ideas. The basic concepts apply to any brand of equipment, not just
ours.  The site is http://www.adst.com
Also, I'd be happy to discuss specific ideas with any of you via E-mail. If you're in
the Boston area, I'd be happy to give in-car demo's.

Best regards,
Bob Hazelwood
VP Product Management, a/d/s/
'93 525i 5-sp, Sharked, BL/ss'd, H&R + Bilsteins, Factory radio/CD, a/d/s/
amps&speakers
BMW CCA (Boston Chapter)

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