Alt whine in the radio

[raveracer77 at yahoo.ca (Rave Racer 77)]

Comm Tech to the rescue.  I'm surprised Chris hasn't said anything, unless I 
missed his post.

Firstly I'd check the grounds, or as I saw someone say earlier, just run a 
lead directly to the neg terminal on the battery which is the same as 
grounding, to test if this is the problem.  I've seen this as a problem both 
from the deck's ground being bad and the amps.  If it improves after this 
test then try to remount the ground wire from the plug into a better 
position.  Maybe new wire or a better contact patch where it meets the 
chassis.  Maybe wire it directly to the battery permanently or at the very 
least look for a better ground inside the dash.  I have heard of the ground 
inside the deck going bad and needing to open the deck to fix it, but I've 
never seen it.
Secondly, move the signal cable and power cables away from each other.  At 
least 6 inches should do.  Inductive capacitance will allow high freq 
oscillations from your power to jump to the signal and out your speakers.
Thirdly, even if there is power jumping over to your signal lines you can 
clean them up with filter caps or crossovers.  They aren't overly expensive 
relatively.
Filter Caps:  One way a capacitor works is basically it's a break in the 
line but it still allows freq oscillations across a gap.  Power is not 
allowed to pass directly while certain frequencies are.  This is a very 
simplified explanation for the context of this subject.  Another thing a Cap 
will do is store a little power to reduce the inconsistencies in power 
fluctuations during a surge or short loss of power.  It reduces strain on 
your cars power system and allows more consistant power to your amplifier. 
You just pick the kind of cap you want and put it in line.  Again very 
simplified and a good Car Audio store should be able to provide good advice 
on choosing the right size and how and where to mount it.  Now you might say 
that I make two conflicting statements, it doesn't allow power to pass 
directly while it provides consistent power but both statements are true. 
The power provided by your car has a frequency to it and that's what you're 
trying to block.  The power provided by the cap is not really provided at 
all, it just charges based on power being drawn into it then it releases it 
when it's needed.  Very simplified again.
Cross Overs:  Now these are a little more complicated.  It's a combination 
of an Inductive coil and a Capacitor.  The two are matched to block all but 
specific frequencies.  You can set them allow all your audio frequencies or 
you can get a couple and block your lows from going into your High range 
speakers while blocking your highs from going into your Subwoofers.  Same 
thing here, it takes a little math and a good Car Audio shop will know how 
to figure out what freq range you are trying to pass and what your trying to 
block.

I'm no expert, just an enthusiast.  I'm sure there's other options as well 
but these are fairly simple to implement.

      Rave Racer
Current:
'91 Jetta GLI 2.0L 16V
'81 Scirocco Mk1 1.8L 8V Digifant 2
'86 Fox
2 GTI parts cars

Gone:
'89 Jetta 1.8L 16V GTX
'87 Audi 4000 Quattro
'72 Triumph GT6

http://spaces.msn.com/raveracer77/photos/
http://www.myspace.com/rave_racer
___________________________________________
----- Original Message ----- 
From: "John S. Lagnese" <jlagnese@massed.net>
To: <julie@menloparkrandd.com>; "A Org, Scirocco" <scirocco-l@scirocco.org>
Sent: Sunday, April 22, 2007 19:25
Subject: Re: Alt whine in the radio


> Noise filter, usually a capacitor with 3 wires. Black - ground, red - 
> power in, blue - power out.
> ----- Original Message ----- 
> From: <julie@menloparkrandd.com>
> To: "A Org, Scirocco" <scirocco-l@scirocco.org>
> Sent: Sunday, April 22, 2007 4:55 PM
> Subject: Alt whine in the radio
>
>
>>I got it. Dont want it.
>> What do I do?
>>
>> _______________________________________________
>> Scirocco-l mailing list
>> Scirocco-l@scirocco.org
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>
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