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Hi-Fi installation 101.



In a message dated 96-12-07 22:39:49 EST, mx@snet.com (Bob D'Amato) writes:

> Hi Igor!
>  Im considering the same Alpine setup... But Im not sure where to begin... 
>  any suggestions?
>  Bob
>  

Also Osman asked me in a prior mail:

>   Now, I've installed maybe 5 head units in various cars. It's a simple
>procedure, especially when you have the nice Crutchfield wiring harness. In
>this case, I do not have one for the Audi, although I could probably call
>Crutchfield and get one. 
>    I'm debating whether I should/shouldn't install this unit in the 200q.
And
>whether I should do it myself or take it to a reputable installation shop
(if
>there IS such a thing). The way I look at it, $40-50 beats three hours of
>frustration with numb fingers. Also, I'm hesitating because I thing this
will
>be much more complex than installing the other units. The others were
straight
>forward.. plug and chug mainly.. some splicing and soldering. This time, I
>don't know what I'm dealing with. I've heard alot of people's talk about
dual
>antennae leads.. poor radio reception... Audi Amps.... etc. What to do...
>If you have any advice on the subject

Over the years I have installed a countless amount of various sound sys in
various cars and the quintessence of this integral experience boils down to:
1. You can not avoid getting some/lots of ignition noise
2. Locating it's source and eliminating it is a major PITA

You have to be really comfortable with electricity to do it right.

The installation itself is simple. I never bother with any adapter harnesses,
Crutchfield or not. I work like a butcher (a very gentle butcher that is). I
usually remove the OEM crap entirely, cut the plugs off  (making sure that I
leave no less than 2cm of wire at the plug for a future reinstallation of the
OEM crap, should it become necessary (never happened so far, though). No one
was nuts enough to destroy an aftermarket Hi-Fi sys. I personally, always
sell my cars with a Hi-Fi intact. My cars usually sound like concerto halls
and the guys who bought them from me always elected to pay a few hundred more
to get a car with a good sys (I always give an option to buy it for less
money with the OEM sys reinstalled).

Bob, first of all keep in mind that your sys will sound only as good as it's
worst sounding component.

Lay out a plan. You have two basic strategies. The first one:
1. Replace just a head unit with a good one, Alpine or Denon being my
favourites. I, personally, have a very low opinion about Sony, JVC and other
mainstream audio. Sony is just as much a hype as BOZO. For a good video
equip. go for a Sony, no doubt here, but audio is just not their stack of
aces. The head unit to be of a high power variety (like 4x25w or something).
2. Replace the OEM single/dual paper cone crappy speakers with the good,
preferably american made, speakers. Make sure that they have heavy (Sr
preffered) magnets and are three-ways with their own passive crossover
networks. They should have composite diffuser cones, rubber suspended. My
personal favourites are Boston Acoustics. German made MB Quarts are OK too,
as well as Japanese made Alpines. 

A second strategy, which is considerably more expensive:
1. Install a head unit with low (RCA) outputs, same brands are recommended.
You will not be crippled by crappy, overworked, single chip based, low power,
class B, clipping on 10v RMS built-in power amplifiers.  A non-reversing tape
drive is, of course, preffered, but they are quite expensive (I cherish one
of my 4 Alpine decks for this, it will go into my new yellow A4TQ this
spring).
Also make sure that the tape deck backs up the pinch roller by 2-3mm off the
capstan when you turn the power off. If the deck does not have this feature,
you will have to eject the cassette manually every time you turn the sys off,
or the static pressure will deform the pinch roller rather quicky and the
music will sound like wow-wow-wow. Music Search and Radio Monitor features
are very convenient also.
All Alpines have the above mentioned features. Ah, one more thing: Alpines
have green illumination only, whereas Denons include little blue, red and
green silicon "condoms" that you can pull over the light bulbs in order to
match the colour of your torpedo illumination. Geez, I don't believe I said
that in my post to Mr. Bob D'Amato himself. Speaking of exposing one's flank!
=8)
2. Get a good equalizer of the active variety, with at least 7 channels, with
a gain of no less than 12db per each channel in the whole frequency range.
Same brands are preffered.
3. Get an active crossover to segregate Highs and Lows in order to separate
the amplification channels. Coustic XM-3 would be a nice compromise here.
4. Get some good class A amplifiers. I would distinguish Alpine, Denon,
a/d/s/, SoundStream. An important hint: NEVER mount an amplifier upside down
on a rear parsel shelf inside the trunk. Air convection directs the heat up,
you'll fry the output transistors in no time (BTDT). Also be VERY careful if
you decide to mount the amps on the trunk ledge under that shelf. The gas
tank is only 10mm below it. My tech once drove a 40mm stinger through the
ledge floor and into the gas tank of somebody else's 100s (non-Q, thanks
heaven!) with a torquey Makita without even noticing it. Did it smell
afterwards! We had to seal the hole in the tank, which was a way worse PITA
than the installation itself. In my Audis I mount the amps vertically in the
trunk, on the other side of the rear seatback.
5. Front speakers: Audi 5000/200 dash will take heavily trimmed small 3-way
Alpines in the factory openings. If you will be using separate's like MB
Quarts and the like, the front doors are the only place for them. In this
case make sure that you mount Basses down low and the Tweeters as high as
possible. Also, aim the Tweeters towards you. Make sure you very well weather
proof the speakers in the doors. The doors are the worst acoustical
enclosures possible, you'll have to use some stick-on sound deadening
material, or they'll will rattle, resonating on lows.
6. Rear speakers: The rear shelf will take anything! MB Quarts can fit in the
factory round openings, their tweeters can be mounted separately, using the
included plastic adapters. Always aim tweeters toward you. I personally like
BA 767 and go through a trouble of cutting 6x9 oval openings with a nibbler
for them. Watch you fingers!!! Keep in mind that the rear seats, C and D
pillar covers and rear parsel shelf will have to come out. Installation of
the oval BA's is a much more involved project than of the round Quarts.
Listen well to both of them in the store and make sure that you *really* feel
that the oval 6x9's sound better than the round 6.5's!!!
7. Rear Bass speakers: hp and alternator permitting, you can get really wild
and install 10" or even 12" dedicated bass speakers powered by a dedicated
amp. The best place for them (short of a huge wooden box, that occupies half
of the trunk space) would be the rear seat backs. Cut the round holes in the
metal and mount them facing forward. Never mind that they will be shooting
into the rear seat backs. Low frequencies have long wave lengths, they are
not as succeptible to the dampening decay as the highs. 
An important hint: pay close attention to the correct phase tuning of all
 the speakers in the sys. One speaker is out of phase=loss of low frequency
due to cancellation!
Another important hint: insulate the speaker cone with a rubber/gummy
compound (I forget the trade name for it, it comes on a paper ribbon and is a
real PITA to take off your fingers. Soak your hands in the water before you
start working with this sticky sh*t). You want to separate the acoustic wave
fronts, created by the front surface of the cone and it's rear one since they
are counter phased and will be cancelling each other. I found the trunk to be
a perfect resonator for the lows and if insulated right, it gives a
velvet-smooth deep pronounced bass. That is why I always bias the lows to the
rear when tuning a high end sys.
8. You can also resort to using a Bazooka tube. They come in a passive and
active (amplified) variety. I mostly installed them in RX7's, 944 etc, where
a trunk was ment to hold little more than a beer cooler.

7 and 8 are quite popular with the *inner city* crowd (switching on a
politicaly correct mode here).
I, personally, think that they are not needed for anything other than rap and
never install this stuff in my cars. If you, like myself, listen mostly to
classical music, then steps in 1-6 will do just fine.

Wiring: solder everything! Fuse protect everything! Feed power to the whole
sys from one point only (+ battery pole is preffered). Find a lead that
becomes hot with the ignition ON and connect it to the "switchable" of the
head unit. This would allow you to turn the sys off automatically when the
key is out of the well. Ground all grounds in one spot!!! Ground them
perfectly if not better!
Run the shortest distances of wire/coax cables possible! Run power leads and
signal leads as far apart as possible! Transverse them whenever you can.
Sorry for a heavy usage of exclamation points, but these notes *are* very
imporant. 
Violaton of the alpha and omega above will cause a creation of a ground loop
and a severe ignition noise.

Hope you have found this helpful. Feel free to ask any additional questions.

Igor Kessel