okay, so my subs and amp were working fine with my old HU but when i installed a different HU i bought from a friend (pioneer DEH-P80MP) and connected everything together again (RCA's into the subwoofer output), the subs make a very loud thumping noise and it doesn't stop unless i turn off the amp. The noise doesn't happen right away but after a few seconds after i turn it on the HU? Could it be my wires? They are wires i bought in a cheap amp kit awhile ago.
what do you guys think? bad HU, amp, rca's or other wires? TIA

 

It could be interference from the HU but I suspect it's something crossed in the wires. DId you take everything out and put it back in when you change the head unit or did you just pop out the old and put in the new...I ask because if you took the whole system out to do whatever and put it back in maybe you crossed the wires. But a lot of times when you have a ground messed up it can do that as well. But honestly the first place I'd check: The RCA jacks...cause if you have the red on the HU to the white on the amp and white on the HU to red on the amp it crosses the signals. Now my girlfriend just put her system in her car and her amp itself is causing interference. Her subs don't thump constantly but they have a constant low bass noise. Something that you would think would come when you're listening to the beginning of a song but it's the amp causing interference. Hope this helps if at all.

 

Make and model of amp, old HU and new HU.

Because it was the HU you replaced, and if all you did was pull the old one out and installed the new one, [used from a friend] I would suspect the problem is the new HU, I would try unplugging the RCAs from the HUs sub out and plug them into the front or rear outputs and see what happens.

If it works then you know the sub output in N/G as long as you are not using the front or rear output and the amp has it's own LP x-over you can go ahead and continue using them, you only loose sub level control. 94

 

Thanks. I just took out the old HU and put in the new one. i disconnected all the wires from the old HU to the harness so that i could use the harness in the new HU. maybe i connected the HU wires to the harness wrong? im gonna go double check the RCAs and stuff. anybody else have any ideas?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fcm &raquo;</TD></TR><TR><TD CLASS="quote">Make and model of amp, old HU and new HU.

Because it was the HU you replaced, and if all you did was pull the old one out and installed the new one, [used from a friend] I would suspect the problem is the new HU, I would try unplugging the RCAs from the HUs sub out and plug them into the front or rear outputs and see what happens.

If it works then you know the sub output in N/G as long as you are not using the front or rear output and the amp has it's own LP x-over you can go ahead and continue using them, you only loose sub level control. 94 </TD></TR></TABLE>

Old HU Panasonic DF200U, new pioneer DEH-P80MP
amp is sony xplod xm-3001sxd
subs are 2 12in kicker solo barics( not sure model#)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fcm &raquo;</TD></TR><TR><TD CLASS="quote">

Because it was the HU you replaced, and if all you did was pull the old one out and installed the new one, [used from a friend] I would suspect the problem is the new HU, I would try unplugging the RCAs from the HUs sub out and plug them into the front or rear outputs and see what happens.

If it works then you know the sub output in N/G as long as you are not using the front or rear output and the amp has it's own LP x-over you can go ahead and continue using them, you only loose sub level control. 94 </TD></TR></TABLE>

Well i tried plugging the RCAs into the front and rear outputs, same stupid loud thumping noise. btw the thumping noise is VERY loud! all the wires look to be connected correctly. must be the new(used) HU like you said fcm.. thanks again!