So yesterday I finished installing an aftermarket head unit in an '07 A4. I noticed that the rear door tweeters are hissing a little (sounds like white noise) all the time now.

When it got dark out and I put the headlights on, that hiss became a full buzz. Quite annoying. Have any of you heard of this happening before? If so, are there any fixes?

Thank you.

 

ok chances are, the aftermarket head unit also has a built in amp, usually aorund like 35-45 RMS watts to give the speakers a boost, audi's head units give a very little signal in the head unit and the wires go all the way to the trunk where an amplifier is hidden on both the left and the right side. from there the signal goes to the head lights

the problem is coming from the wire going from the aftermarket is at high frequency now when before it was at low frequency, then it gets fed into an amp where it is put to an ever higher frequency and develops the hiss


you can fix ur problem by getting a JL Audio clean sweep which eliminates the problem entirely

 

Thanks man.

 

or you can buy a filter for the engine noise, which is what I assume you are experiencing now.