keep hearing noise through my sub...

[rbfb2101]

i never had a problem with my current system until i hooked up another amp and sub to test them, then when i hooked up the original system again i hooked up the positive and negative wires that go into the amp backwards a few times and kept blowing fuses until i figured it out. stupid, i know... the neg cable was red and the positive cable was black instead of the other way around like it should be, i didn't even think about it.

anyways, after i got it all hooked up again, i noticed a constant whirrring noise coming from the sub. the noise is present with the volume turned all the way down, with the sub turned off through my stereo, and you can hearing things like the door open buzzer through the sub. i bought another sub and am still having the same problem. i was thinking that the amp was bad at this point but my friend was telling me about a pre filter or something that filters out noise.

i don't know much at all about car audio so i was just wondering if you guys think it's the amp or if that filter thing would work. the sub is a pentagon shaped 12" sony explode 1200w and the amp is a pyramid pb449x 1000w.

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[rbfb2101]

update:

went to a car audio shop today and they bench tested my amp and said it was good. they also said the pre filter things are crap. the guy wasn't sure what the problem could be without looking into it more heavily which i didn't want to pay for.

i went home and changed it from bridged to just one channel and the noise was cut in half. it's a lot better but still hear the whirring noise enough to annoy me. i also noticed that i only hear the noise when the rca cable is plugged into the L on the amp. i can plug either RCA cable, L or R, into the L on the amp, and only get the noise from the L.

so, any ideas now?

 

[dbman150 5,000+ posts]

find a new ground

 

[DbzArson 10+ year member]

problem: sony xplod.

 

[DbzArson 10+ year member]

probably alt whine.

ground h.u.

sounds like you probably have the awesome pioneer head units from walmart?

 

[rbfb2101]

probably alt whine.ground h.u.

sounds like you probably have the awesome pioneer head units from walmart?

so try new ground? i have it grounded to the metal on my trunk, drilled a hole and scored it with a grinder to get bare metal and bolted it down. the ground was fine before i popped those fuses, kinda makes me think it's something else.

not a cheap walmart unit either, a pioneer deh-p7800mp. was like $400+.

and it's not alternator whine because i get the noise with the engine off too.

 

[gtbike900 10+ year member]

but still a pioneer ground rcas and check also for a bad rca try pluging the right rca in the left on the amp it it does not make a noice you have a damaged rca

 

[rbfb2101]

but still a pioneer ground rcas and check also for a bad rca try pluging the right rca in the left on the amp it it does not make a noice you have a damaged rca

are pioneers known for having bad ground or are you just saying they are shitty in general?

the noise is there whenever either rca is plugged into the left on the amp. unplug the rca from the left on the amp and the noise is gone.