Hi just finsh install my amp now i'm getting this humming sound coming out of the speakers and it gets louder as i rev. i think i could be the ground connection. At the moment i only have it grounded to a point in the trunk. do i need to run the ground back to the batt?

thanks

 

Does the frequency change with the speed of the engine? If so you have alternator whine and need a "choke coil" installed in series with the (+) power line. It needs to be big enough to supply enough current (amps) to your power amp. They're not that expensive.

Normally one good ground is enough. The key is a good ground - make sure the paint is scraped free from the area and that the screw and termimal/bare wire is very tight.