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Subwoofer thumping while muted?

G

getsum111

Yes I am a Pirate, 200 years too late.
Joined
Apr 5, 2005
Messages
4,188
Location
Pillaging in Freedom, PA.
Hello all. I feel like a noob, but my searches turned up nothing, can't find right wording. :shrug: Anyhow, recently my sub has begun to "thump", even when there is no note playing. It will also do it when I mute the HU. It does not do this when the HU is off. I have a Panasonic Hu w/ sub pre-amps, which are run to an MTX Thunder 280, bridged, to a 12" Infinity Kappa Prefect. Door speakers, which do not "thump" at all, run off a separate amp. I use a dist. block for both power and grounds, and dist. block is grounded under seat.

If anyone has any suggestions, I'd appreciate it. Not sure why, but it feels like Signal/RCA issue to me. Anything I can check before buyin' a set of new RCA's I may not need? Thanks.
 
does it happen when the car is sitting still? wondering if it's a loose connection that becomes apparent when driving over bumps, etc...
 
Do you have an extra pre-out on your HU? Try swapping pre-outs and see if anything changes. I had a similar problem which turned out to be a bad pre-out on my sub channel. Switched the RCA's over to the rear pre-outs and my 'thump' went away.
 
My old kenwood would do that after working it too hard, "Thump, pause, thump, etc." After playing it loud, it would cut out and do as you described. My cooling fans didnt work and possibly it was getting too hot. If you turn the car off or turn off your HU does it go back to playing normal? Mine "thumped" even when the music was coming from the HU. If I reset the deck it would play correctly. Pioneer Deck BTW.
 
Does it moving or sitting, hot or cool. If I turn off the sub pre-out, it still does it. When it stops raining, I'll double check my grounds and such. If that doesn't do it, may run an RCA from one amp to the other, as I'm using all the pre-outs.
 
Why not do the easy tests 1st... just unplug the rca's from the sub amp, and turn the HU on and off and see if you have pop.... if your RCA's are long enough, you can try using the 4-channel RCA's to get signal to the sub, or swap them around and see if the problem moves with the RCA's or stays at the amp... Should narrow it down pretty good... If not you know you have some more testing to do..
 
My last amp did that.. Thumped when all the way down and 1 speaker seemed to hit harder than the other , so i checked out everything and found that when i moved the RCA jacks on the amp the thumping went away and the "weaker" speaker hits harder so i just sold it and got a new one... :shrug:
 
Well, ran new ground from dist. block to rear seat bolt, used much bigger ground wire (1/0 IIRC, it was given to me for free from my brother). Also a new set of RCA's from HU to sub amp. Now, I get a quieter thump, and only when I press brakes? :confused: Gonna try to check the + cables again tomorrow.
 
getsum111 said:
Well, ran new ground from dist. block to rear seat bolt, used much bigger ground wire (1/0 IIRC, it was given to me for free from my brother). Also a new set of RCA's from HU to sub amp. Now, I get a quieter thump, and only when I press brakes? :confused: Gonna try to check the + cables again tomorrow.
Click to expand...

I had that issue along with when the headlights were turned on too, UPGRADE the ground wire from the battery to the chasis up front. Should take care of that.
 
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