New Pioneer Unit - how to stop hiss - going mad
 

Greeting to All,

Thank you for stopping by. I recently had a new Pioneer AVH-P4400BH unit installed into my 2005 Camry XLE with the JBL premium package which includes six speakers, subwoofer and amp.

After installation, the front speakers produce an audible hiss when the car is on. When the car accelerates, a high pitch noise can be heard through the speakers. The noise isn't loud but noticeable. These noises will occur wether the unit is turned on or off.

I went back to the installer, and they said that noise(s) is to be expected since I am using the factory amplifier. They said the problem is due to the high voltage of the unit and it must downgrade the line to match the amplifier voltage which results in the hiss. This sounds like bullsh$t to me. It time to get my hands dirty and learn how to fix it myself.

Where should I start? Is the factory amplifier the cause? The unit not grounded sufficiently? Better shield wiring?

Unfortunately it's not BS. Rarely does an aftermarket deck co-operate with a stock amplifier. of course, the shop should have told you that up front.

Try grounding the RCA shields at the heat unit.

Thanks for feedback. I am assuming I ground these RCA jacks to car frame.

^ its not likely to make a difference.

If you really really really want to get rid of the hiss, maybe try one of those line out converters to match the voltage. Also ground the factory amp to the head unit.

Unfortunately, nothing is likely to get rid of the hiss, unless you get rid of the factory equipment and go all aftermarket.

Also, check to see if they are feeding the signal to the factory amp via RCAs or amplified signal.

I had this problem in my vibe and when I took the signal from the RCAs to feed the factory amp the hissing reduced significantly, but not completely.