Hi, iv'e seen something very strange for the first time. Iv'e installed by sound from old car to new. A 2000w sub on a 2500w amp. 1 x hi to low convertor and speakers still run of factory radio. Amp mounted on rear seat. When the volume is all the way up and the trunk is open every thing seems fine. But when the trunk is closed and the volume turned softer until 0, the sub keeps on pounding, very loudly. But if the 1500w amp is tested, everything is normal. Could this be because of the hi to low convertor or because the speakers are still running on factory radio?

sounds like somethen is touchin ie rca's?

or i always say this check ur ground.

My friend had a problem similar to this, basiclly he had melted his power cord under the hood and never checked it, so it worked fine but it did like u said the speakers where movin to there own little beat.

So i think somethin is touching.

The first install we did, we used a two pin fuse which melted like ice on a warm day. I replaced the power cord with a thicker one. It is mounted directly under seats to the body. They used a 10g wire which i think is a bit to small. So if the rca's is touchin, then to what? After that we used a fuse block. But no luck. Is there a way to fix this, or should I take everything apart and try again to pin point the problem?

If the amp is on a certain level you can still hear the bass bound if you knock on any panel where the midrange speakers are. The higher the level on amp goes the louder and more continious the pounding goes on. So it must be rca's?