Bizarre problem - thump from subs related to back seat

[Lowkey 10+ year member]

Getting thump from subs when rear passenger seat is got on or off and today noticed it will do it when I touch it with a blanket lol. No wires in or under this seat unless they are factory and hidden. Touching it with my hand wont do it. Posted a video of it happening here: Video

Never mind, it turned out to be the remote gain knob. Once I unplugged it the problem disappeared.

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[1aespinoza 10+ year member]

Never mind, it turned out to be the remote gain knob. Once I unplugged it the problem disappeared.

Was the wire running near the seat? This is wierd, even though knowing the gain knob was involved.

 

[Lowkey 10+ year member]

Was the wire running near the seat? This is wierd, even though knowing the gain knob was involved.

The wire was running under the trim next to the seat. It was in a fairly deep "well" so I know it wasn't being pinched.

I have no idea how touching the seat gently with a blanket affected the wire, makes no sense to me. Even more strange is I had already played with that wire and even stepped on the trim to see if it would cause noise, nothing.

 

[SlugButter]

The wire was running under the trim next to the seat. It was in a fairly deep "well" so I know it wasn't being pinched.

I have no idea how touching the seat gently with a blanket affected the wire, makes no sense to me. Even more strange is I had already played with that wire and even stepped on the trim to see if it would cause noise, nothing.

I would bet static electricity was building up and affecting the ground wire somehow when touching the metal, which could be amplified into your subwoofers. It’s an odd problem even if the bass knob isn’t a factor. Maybe it routes power through the amplifier circuits in just the right way to get a feedback in the subs when the bass knob is connected. Where is your sub amplifier grounded?.

 

[Lowkey 10+ year member]

I would bet static electricity was building up and affecting the ground wire somehow when touching the metal, which could be amplified into your subwoofers. It’s an odd problem even if the bass knob isn’t a factor. Maybe it routes power through the amplifier circuits in just the right way to get a feedback in the subs when the bass knob is connected. Where is your sub amplifier grounded?.

No issues since unplugging the knob so I got to believe its the source of the problem. Maybe there are other contributing factors, no idea what they would be though.

The ground runs thru the floor under the opposite seat and to the frame. I have it sleeved and am using a rubber grommet. I used a seat bolt originally but did it the right away to try and fix this exact problem. Ironically my voltage is virtually identical on the frame vs the seat bolt.

 

[SlugButter]

No issues since unplugging the knob so I got to believe its the source of the problem. Maybe there are other contributing factors, no idea what they would be though.

The ground runs thru the floor under the opposite seat and to the frame. I have it sleeved and am using a rubber grommet. I used a seat bolt originally but did it the right away to try and fix this exact problem. Ironically my voltage is virtually identical on the frame vs the seat bolt.

Seat bolts usually work fine for most cars honestly. Seats are bolted to the frame. Once you get up to a certain power level and need more then a single 0 gauge ground I would start using the frame directly.