RE:Audi audio questions (long/detailed)

[Sargent Schutt <sargent@novagate.com>]

The following is my 10 years experience with aftermarket systems in my
Jimmy, 5ktq, 90q20v and 91 200q 20V. There may be other ways to
accomplish my results (or better), but the following steps will result
in a sytem with the closest thing to ZERO noise I've heard from any car
audio.

To eliminate alternator whine (particularly in the 5k/100/200/V8) where
the head unit is in-dash and the amp is in the trunk powering speakers
front and rear:

1. END POINTS: Wire all power (positive) to the battery (located under
the rear seat). Use separate, appropriate-size fuses for each positive
power lead. Wire all ground (negative) to the *same* location (I used
the rear deck). Be sure to clean the contact point so that the bare
metal is cleanly exposed. Whichever spot you choose, I recommend using
paint remover, as it will not remove any galvinization (no rust issues
and bad grounding in the future).

2. WIRING LOCATIONS:

POWER: From the head unit, run the power lead and ground lead up under
the carpet along the tranny tunnel. With the rear seatback removed,
drill a hole to run the neg lead into the trunk to meet the amp ground
at the common grounding point. Be careful to file the holes and cover
the fresh metal with a touch of Rustoleum and some duct tape to prevent
against future chaffing/rust (a rubber bushing would be better).

RCAs: Run high-quality shielded RCA cables from the head unit under the
steering column and along the drivers side footwell. I placed mine
tightly under the plastic door-sill cap. Drill holes in the rear
seatback off to that side to run the RCAs. Same file/paint/tape
procedure to prevent chaffing.

PASSIVE CROSSOVERS: (used with component/separate type speakers) Mount
these to the metal underside of the rear shelf and run the wires to the
appropriate speakers, FRONT and REAR. Passive x-overs are very sensitive
to noise issues.

SPEAKER  WIRES: Run them up the tranny tunnel to the front speakers. Try
to keep them away from other power wires where possible, but the speaker
wire is much less susceptible to picking up noise as the signal at this
point is post-amp, and post-x-over.

SPEAKERS: Make sure the wiring will NEVER come in contact with the
speaker - it is very annoying when this happens. Mount the speakers
securely so that they will never come loose. If you can use stainless
bolts with locking washers and aircraft nuts (harder to steal, too).
Otherwise sheetmetal screws.

IMAGING: I found, in the 91 200q (same as 100/V8), the best imaging came
by mounting 4" + tweeters in the dash, with the tweeters pointed up
toward the center of the windshield just below the rearview mirror.
Mount the 4's in the holes provided by the factory. I mounted 6"
speakers in the doors where the BOSE speakers used to live. My a/d/s
were a little too deep, so modificattion to the inner door was
necessary; so beware, you don't have a lot of depth there.

I mounted 6" speakers in the rear deck BOSE holes, and mounted the
tweeters in a couple of tan (my int color) plastic tweeter
housing/stands from a non-Bose 100/200 these stands can be found in any
interior color (from boneyard). These stands are designed to sit flush
against the speaker grill, just behind and to the outside.  Angle them
in toward the center of the car (drivers armrest area). This directs the
sound from the far side to your ear, helping to offset the fact that you
are relatively closer to the right/left side of the car.

The resultant soundfield is far from perfect with respect to proper home
audio, but given the environment it is excellent. Keep in mind that from
the outside the entire stereo looks bone-stock, except the head unit (no
aftermarket speaker grills showing). There is zero perceptible
alternator noise (only a teeny tiny bit but my ears are hypersensitve,
99.999% of the world couldn't hear it if they wanted to).

As far as the particular tone you're getting out of your system, that's
a reflection of the equipment you chose. I have very clean, relatively
crisp bass from a 10" non-ported box in the trunk. Yes, the leather back
seat is harder to drive through than cloth, but if the sub you choose is
good and you give it enough *good* power, it should still sound
relatively crisp. I have not cut into the rear deck. That might help.

How good do you want your stereo to sound? How fast do you want to go?
Well, how much do you want to spend? Remember, though, by the same token
that you don't have to buy a new car to get a quality fast car (witness
our Audis), neither do you have to buy new audio equipment to get
excellent-sounding equipment. The high-end variety is generally
well-built and can be had for pennies next to new. I spent well under
half what new would have cost on my complete system, not to mention the
money I saved on installation by doing it myself.

There are headaches abound in the audio department, hopefully this will
prevent a few. Sorry for the excessive bandwidth here.

AUIDIo s, amigos

Sarge

91 200q Eclipse am/fm/cd, a/d/s 50x6 amp+ a/d/s electronic x-over, a/d/s
T-4-6 (front), Boston 6.2 Pros T-6 (rear), Punch Audiophle 10"
non-ported sub (trunk)

You wrote:
>Finally decided to junk the Bose system in my car. The installer (a 911
car nut) eliminated any potential alternator
whine by hooking up amps power and ground leads directly to
the battery.
Where is the battery in this particular car?   I ask this because you
don't necessarily eliminate alternator whine simply by running your
ground to the battery.  I would use the shortest lead possible.
2. The sub sounded muddy.  Q: Is this related to the transfer function
of the =
sub/backseats are metal and there is no outlet for low frequency =
sound to go upfront?
3. Sub also has dips during extremely demanding tracks.Thor
V8q ( getting heavier each day)
=00=00

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