I recently just took my subs out of their old box and put them into a new one because the older one had water damage to the wood. However while the sound is much more cleaner than the other box, when I have my radio turned off, I get this humming sound coming into my car that is much louder than the cars engine or exhaust and was told that is feedback from my amp ( Sony Xplod 500 watt amp). Not a big amp but it sounds as though my subs are on very low playing a song with very low bass. While this could be fixed by taking it back to the same guy Im unsure as to whether they will charge me again for this stupid thing. Anyone familiar with amp wiring and setups and would know how to eliminate this sound from my speakers. Before he put the subs into the new box and reconnected the wires there was no feedback from my amp and only happened when my other sub was getting put in. He eliminated the noise but now it came back and was wondering if it had anything to do with disconnecting and then reconnecting the wires to the subwoofers. Is there something on the amp that needs to be adjusted because again taking it to this guy is a pain in the @$$. Any advice is greatly appreciated. :notworthy

Try turning down the gain on the amp a bit. You also might want to try installing a ground loop isolator. It goes inline with the signal to the amp.

its actually not the amp. i had the same problem but it eventually went away. its because our stock headunits remote switch is delayed. aftermarket headunits basically have a remote switch to where when it is turned off the amp is turned off but our stock head units are delayed and thats where that humming is coming from.

http://www.cybergiftcenter.com/applications/search/itemdetails.asp?oid=21&sku=CP-Trunkloc&mpn=Trunk-loc

that should fix the problem. what it does is it creates a "fake remote trigger" and when u turn ur car or radio off you wont get the humming noise anymore. i was told that it was very easy to install. i never got it because that humming went away and it doesnt harm your system at all.

I think the humming went away because normally i just turn the switch off after turning off the head unit but today I just left the switch on and there was no noise. THe guy who actually installed everything for me told me that it was a delay from the headunit to the amp and the only way to get rid of the sound was to turn the amp down but said that it will still be there just not as noticeable.