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High frequency noise in the audio system

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Old 01-24-2005, 09:38 AM
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High frequency noise in the audio system

Hi all,

Searched the forum but nothing turned up. I am having a problem with my audio system and have not been able to figure it out.
I have a decent audio system installed in my car about 2 weeks ago. There are 2 amp, one for sub and one for driving speakers. I only have the front pair speakers installed for the moment.
Often in time, I get this very high frequency whizzing sound, it sounds like when your ears are ringing in a very quiet room. I do not get it consistently, sometimes I will get it after 10 mins of driving, other time, I might not get it after 1 hour of driving. It never happens when the car is first started. I was suspecting a temperature issue with the amp.
This noise come from both of the front speakers, and do not seem to go up/down (both in pitch or volume). It is a constant noise. My friend suggested that it is engine noise due to faulty ground wiring or bad contact in the wiring, while the professional installer (not a very good shop to be honest) said it is not because it does not go up and down with engine speed. They said it's an amp issue and they want me to buy a $799 amp from them.
One thing to note is this system does not get "clean" signals, it hooks up a RCA converter to the stock speaker wires to get signal. My friend said that might be the problem.
Anyone have any advice or pointers for me to resolve this issue?
I spent way too much money on the system to have to put up with it ... I want to have the shop resolve it.
Old 01-24-2005, 05:22 PM
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W204 C300 2010
If you suspect a amp temp. problem. Take a hair dryer and heat up both amps, do not use a heat gun! If you get the noise, let things cool down. Then heat up one amp at a time to isolate which one.

You mentioned the hi-to-low level converter (speaker to line level), some are passive and others are active, if it is an active type, then make sure is has good power/ground connections. If passive, make sure all the RCA connectors are making good contact along with how the input wires are sliced into the factory harness.

If the sound does not rise/fall with engine speed, then you probably do not have a ground loop problem.
Old 01-26-2005, 01:12 AM
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lower your amp output volume.
Old 01-27-2005, 07:23 PM
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What equipment are you running... brands of RCA, Speakers, Amps etc etc. And could you take pictures of the install? Try lowering the output of the Hi-to Low converter.

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