hi pitched noise???

[7point3]

hey

i dont know if this is the right area bit it involves my sound system so heres my problem.

the other day i started my sound system and when the car is on accessories there is a low buzzing through all speakers and sub.

when the key is turned to on it changes to a high pitched squeal, and when the car is started the pitch changes with the revs.
i tried turning the head deck off but it doesn't change it at all.

i dont have any idea about electrics etc, i know its some form of feedback but i have no idea what, any idea would be helpful.
i was told maybe the alternator or something but not sure.

cheers

[berad]

engine whistle.

check the earth point on the amps, make sure its secure and that the surface is roughed up a bit for better cont. Failing that could also be RCA leads to close. Theres a fair few reason as to why you get it.

[gonnaenodathat]

also, buy a voltage suppressor ! goes inline with the stereo power and stops that noise but will be caused by some other issue...

[holdenboy]

Head unit brand?
How is the system wired, for example: subwoofer is powered from the amp and the speakers are powered from the head unit.
Did you do anything to the car / system before the noise started? Could have been just about anything, like changing a tyre or servicing the car etc.

[7point3]

the head unit is pioneer,
the whole system is through the amp.
and it had been running fine for last 2 months as is and i was re fitting a speaker and when i restarted the car it was happening, ive tried disconnecting all speakers and reconnecting one by one but it doesnt change.

ive tried another rca cable but doesnt change anything, we think we have it down to the head deck, im just waiting on a mate to bring his old one round to confirm.

i havent had my licence for 3 months and all ive been doing is fixing the car and 2 days before it decides to screw up again!!!!

[TMM]

Alternator whine. I had this, the fix was to move the ground cable away from the amp, crossovers (i have mine boot mounted) and any speaker wires.

[StoneX]

RCA ground fuse is probably blown inside the head unit. It usually happens when RCAs are plugged in when the head unit is on. You'll need to check if it's that and then get it fixed.

To check (you might need a second set of hands):
- Get a bit of wire
- Pull head unit out but leave it all plugged in
- Touch one end of wire to the head unit's metal chassis/shell
- Touch the other end of the wire to the outer metal ring of the RCA sockets while your RCA leads are still plugged in
- Turn stereo on... Is noise gone? If so, your fuse inside the head unit is blown. If not, keep looking for problems