Whistle?
Whistle? I have been getting a whistle sound from my car. It increases when the RPM's goes up. Its weird, at first I thought it was coming from under my hood. Then just now I carefully listened and it sounded like it was coming from the rear. I pulled over and there it was, it was coming from my damn rear speakers. Has this happened to anyone? If so how did you fix it? Please help cause its driving me crazy. Thanks!
if you have aftermarket amps or radio in your car, your factory radio ground is probably at fault. OR you could go and get a bigger amp for more headroom, so that you can phase out that engine whine.
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
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From: Decatur, TN (N-W of Athens)
Your ground isn't grounding properly, that's what's they're saying. If you had an older car, with say a CB Radio, or AM radio, you'd have experienced this. To help correct that they made shielded spark plug wires. It picks up that whine-buzz from the ignition.
It could be EMI (spark noise) or it could be alternator
whine. EMI wants cable shielding. Alternator whine
wants better supply filtering (amp internal filter caps
can go bad, external LC filter in the pwr feed might be
the ticket). But might start with the ground screw to
sheet metal and the general cleanliness of the power
and ground connections. The battery "ought to" soak
up alternator ripple but if its internal resistance is high
(or external resistances between alt and battery) the
current ripple will not be held down to flat voltage.
If you have a junk (but functional) speaker and a
capacitor for DC blocking, put that assembly across
the rear amp power & ground and see if you hear
the same tune. Try it at the alt and at the battery
too. A tight power distribution network will be all
the same, and reasonably quiet (quiet enough for
internal filtering to finish the job). One that's got a
loud whine on the alt end and a quiet battery end
has too much wiring resistance (crust, loose, etc.).
An alternator with an open rectifier in the pack, will
create much more current ripple and be very noisy.
But you would expect this to bother both front and
rear. With a multi-amp system and only one hosed,
have to think it's more to do with one amp's supply
decoupling.
whine. EMI wants cable shielding. Alternator whine
wants better supply filtering (amp internal filter caps
can go bad, external LC filter in the pwr feed might be
the ticket). But might start with the ground screw to
sheet metal and the general cleanliness of the power
and ground connections. The battery "ought to" soak
up alternator ripple but if its internal resistance is high
(or external resistances between alt and battery) the
current ripple will not be held down to flat voltage.
If you have a junk (but functional) speaker and a
capacitor for DC blocking, put that assembly across
the rear amp power & ground and see if you hear
the same tune. Try it at the alt and at the battery
too. A tight power distribution network will be all
the same, and reasonably quiet (quiet enough for
internal filtering to finish the job). One that's got a
loud whine on the alt end and a quiet battery end
has too much wiring resistance (crust, loose, etc.).
An alternator with an open rectifier in the pack, will
create much more current ripple and be very noisy.
But you would expect this to bother both front and
rear. With a multi-amp system and only one hosed,
have to think it's more to do with one amp's supply
decoupling.
