Hey guys i got a Rockford Fosgate Punch stage 1 subwoofer 4 ohm
and ive got a sony xplod xm-2100gtx amplifier
my head unit is a pioneer deh-p4700mp
The problem is that every so often ill start to hear a thumping in the speaker, and when i roll my window up and down--or just hit the switch--ill hear a slight feedback. ive checked my ground and its good. Also my rca wires are ran on the opposite side of the vehicle from the power wire. Does anyone have the slightest clue what could be happening.

 

Try grounding in another location.

 

If nothing helps - try swapping an amp with your friend. Some amps, especially I noticed it with MTX (full-range is the worst) are very sensitive to noises in their power supply.

 

the only thing it can be is a ground, find it and fix it.

 

also might want to check your voltage. the rockford punch amps tend to motorboat and/or distort very easily. turn the gain down a bit, and make sure the amp is getting plenty of power (right gauge power cable and voltage that isnt dropping too low).

at my store i cannot turn the rockford amps i have on the display boards up past %50 on the gain or else they start motorboating (however in a car i can crank em assuming the instal is up to par). the same 600w alpine amp in the same pod however i can turn all the way up without it distorting like that. im pretty sure it has to do with the effinciency of the rockford punch amps.

now im not talkin bad about them just stating what i have seen over the last two years of working retail.

 

Where is your ground located? It 'should' be routed down from the amp, but my ground goes to the back pannel near the hatch release. NOT the taillights. The local sterio guy told me that's where he usually routes his grounds.