I just installed my new headunit. All the connections are good and grounded. When evey it is on you always hear a hissing sound. Almost like feedback from the car itself. As I accelorate the hissing is in tune with the motor and anything else I use electrical. Any suggestions? Thanks all!

 

Pretty common occurance with audio installs. Couple of things ... did you use line-level converters? (These tend to cause a lot of it.) How did you install the headunit. Was it with a cable harness adaptor or did you splice? What other components were added / removed? A bad ground is a #1 suspect but there can be others too. You may need a line filter on the 12V+ depending on your system.

What you are hearing is indeed feedback from your car electrical system leaking to your audio system/speakers. (Sound increases in pitch when revs increase.) In older cars, sometimes messing with spark plug wires can cause the same problem but this is not the case with ours. Thanks goodness.

 

Thanks for the responce. I got an adapter but i still had to splice the wires from the new unit to the adapter. I have no idea what a line-level converter is, so that would be a no, lol. I didnt add anything just popped out the old unit and plugged in the new one. Line filter? Thats sounds promising, but what do I need to do. Thanks

 

Enging noise is most comonly a product of a bad ground. either take the ground from the headunit and find a very clean ground (no paint, rust.. etc) or run a small wire from the headunit ground back to the ground of whatever amp you're using (if you have an aftermarket amp, too) this will complete the loop.

I used to service electronics, and sometimes it is the actual hardware itself, AKA the ground connections inside the unit are not quality.