Whenever I turn the gain up but not to full I start getting a high pitched frequency playing though my speakers that matches the engine's RPM's. Now I've been told it's from many things but I just wanted to hear what you guys think it is.
A few possibilities: 1. bad ground connection to the amp (try moving it around), very common problem (ground looping) 2. bad wire routing from HU to amp (if line-level, good chance on this) 3. cheap RCAs (weak jackets) 4. power run next to RCAs causing RF noise
Michael, 1. Are your ground wires 10ga or better? 2. line-level means you have speaker wire running to the amp. Since you have RCAs, not the case. 3. ok 4. Power should be run on the opposite side of the car from the RCAs. If they're run next to each other, the RCAs will pick up the alternator noise from the power lead. Power on drivers side, RCAs on passenger.
try using a ground loop isolator. radio shack sells them.
also make sure none of your speakers in the doors etc have the speaker terminals grounding out to the car body metal.
if you're using an amplifier, turn down your gains. that's a very common source of noise. having them turned too high up to compensate for buying a weak amplifier.
Matt: My ground wires are 4ga and my power wire is run on the driver's side of the car and the speaker wires are run on the passenger.
Glasswolf: What exactly does a ground loop isolator do? What do they cost? I have a JL Audio 300/4 amp so I'd like to hope that it's not because I have a weak amp.
It's definately not a weak amp, just make sure to set the gains correctly, possibly go to a shop and get them set with a voltmeter. Check the head unit ground, if it's grounded to a stock ground location try grounding it to the chassis. A ground loop isolator just filters out noise and is very cheap. I prefer to try my best to fix the problem before using a ground loop isolator. Also check the power wire routing in the engine compartment, make sure it is as far away from ignition wires, coil, alternator, the distributor, and other electrical components as possible.