Ok, I have a ground loop problem and the only solution that seems to work is to use a Ground Loop Isolator hooked up to the RCA's on the amp. I just got the system installed recently and took it to 2 different shops and they were both not able to fix it. I went to the first store where I had purchase and installed my system. After having the car for the whole day, they were unable to solve the problem without using the GLI.
I did an A/B comparison with the GLI on and off and the difference was night and day. With the GLI on, the highs was harsh and the lows were muddy at higher volume levels. With the GLI off, the sound was completely clean on the highs and lows while playing at high volume. This really kills me since I am forced to use the GLI and compromise the SQ.
The noise is classic alt whine. Its only there when the engine is on and the pitch changes when the gas pedal is pressed. The noise is very faint and one shop even went so far as to suggest its "acceptable"! I can tell its there though and it drives me nuts.
One shop I went to, we replaced the RCA's with $100 monster cables. We first ran it over the car seats and carpet and the noise is gone. When they ran the cables underneath the carpet the noise came back! So I ended up just using my existing RCA's.
The other shop where I left my car for them to work with did a lot of things that one would do to get rid of ground loops i.e. ground at amp, deck to batt. neg. grounding rca to chasis, moving deck ground to behind dash, disconnecting antenna cable, switching decks, etc. They pretty much did everything but one thing that interested me was that they said they used their highest quality RCA running over the seats and carpet and with the Deck outside of the dash and the noise was still present.
The only other thing I can think of is to do the Big 3 upgrade or 2 out of the 3 which are: Battery negative to Chasis and Engine block to Chasis. My installer said that with my system it won't help so they didn't do it.
What do you guys think? Should I just live with a compromised system? Will upgrading 2 out of the Big 3 make a difference? If there is anyone living in the 808 state that is willing to take a look at my car and help me out, I would really appreciate it.
My system is pretty simple:
Rainbow SLC 265
Stock Rears (powered by HU)
ARC 12D2 Sub
ARC 4150-XXK (powering rainbows and arc sub)