ive had this problem with CB radios and RF modulators. the only thing i can
think of is try and find some sort of EMI shielding (some sort of shielded
RCA cables and maybe shrouding to go over all wires) for everything behind
the dash and shield it all. personally i just quit using a CB radio and RF
modulators. i know that monster make a shielded RCA cable and that wire
shield is available but your gonna have to look for it. lemme know if it
works. -Nick


"Mike O'Malley" wrote in message
...
Hello all, looking for a bit of advice, I've run into a strange problem
with
my intall, and I can't seem to figure out where it's coming from.

Rough outline- MTX Thunder 4244 4 channel amp, getting fed from a Kenwood
CD
deck. Fronts- Infinity Refrence 6402cfp Rear- Infintiy Kappa 692.5i

Problem- Whenever the engine is running, there is electrical noise that
varies with engine speed, but not with volume; it's just as loud with the
volume all the way down as it is all the way up. OK, I think, bad ground;
sheetmetal screw in the trunk floor was pretty bad. Relocated, used a
wire
brush on an angle grinder to get it to bare metal (power tools are fun!).
No change. It SOUNDS like it's coming from the rear channel only, but
it's
not affected by the fader controls or gain settings.

On a whim though I tried swapping the RCA's on the back. The problem ONLY
manifests in the rear channel; if I disconnect the rear, problem goes
away,
if I send the fronts to the rear, problem is still in the rear.
Disconnecting the rear RCA lead and setting the amp to 2 channel input
still
results in noise in just the rear channel.

Could this be an internal problem with the amp itself, because, frankly,
I'm
at a loss to figure this out. The rear speakers come with an external
crossover, if I disconnect the tweeter, the noise all but dissappears.
Could the external crossover be the problem? Or would it just be
filtering
out the noise to the woofer?

Any ideas would be greatly appreciated.

Thank-you,
Mike O'Malley