negative_silent
Junior Member
This is my first relatively big build. I have installed about a dozen aftermarket systems before (complete with headunits, amp for speakers, amp for sub), so I do have all the basic knowledge plus some. I have this constant subwoofer thumping noise that I cannot get rid of. PLEASE advise.
Car: 2011 Mazda 6
Headunit: aftermarket android gps navigation stereo (similar to this)
Alternator: 370a Singer alternator with Big 3 upgrade
Starter battery: XS Power D1200 (2 runs of Sky High 0AWG to rear batteries)
Rear batteries: 3 XS Power D3400
Amps: 2 Hifonics Brutus BRX2400.1D
Subs: 2 Soundqubed HDC3.112
Grounding for the amps is not an issue. I have two battery bolted to the bare frame of the car and the batteries running to one another. All 0 gauge running from batteries to amps.
When I had the 2 amps strapped, the thumping happens randomly, consistently, and LOUD. I tried unplugging the RCAs and the sub remote (on the master amp and slave), the thumping does not stop. Lowering the voltage on the amp itself and the bass boost all the way down does not lower down the loudness of the thumps. Thumps will happen even if the headunit volume is 0. If I turn off my headunit (android tablet?) then the amps will turn off after a couple of seconds too.
I have the remote for the amps connected to a relay (since I have 4 amps total) taken from the headunit. If I turn off the headunit, amps turn off and the thumping obviously stops. I can turn on the headunit and the subs will be fine (will not thump) for anywhere between 30 secs to a few minutes, and then it would start thumping again. The interval between the thumps is constant but it appears to only happen when the car is running. Also, the engine RPM seems to affect the thumping; the somewhat common pattern (not always) is that when I rev pass ~1300RPM, the thumping would happen. Only sometimes when I am sitting at idle (700-800RPM) will it thump.
I have tried to unstrap the amps (each amp powering a sub). I found that ONE of the subs will thump extremely loud (the one that was set as master when strapping), which lead me to believe that the amp was at fault, so I disconnected the speaker wires from that sub, so that now only the other one is connnected. However, I noticed that there is also a slight but still very audible thump coming from the other sub. I find it hard to believe that both amps are defective from the same cause (I bought these amps from different authorized dealers at different times).
This has been an ongoing problem for MONTHS now and I have tried to troubleshoot it to no avail. If anyone has any idea. PLEASE help.
I can provide any other information or pictures if needed.
Car: 2011 Mazda 6
Headunit: aftermarket android gps navigation stereo (similar to this)
Alternator: 370a Singer alternator with Big 3 upgrade
Starter battery: XS Power D1200 (2 runs of Sky High 0AWG to rear batteries)
Rear batteries: 3 XS Power D3400
Amps: 2 Hifonics Brutus BRX2400.1D
Subs: 2 Soundqubed HDC3.112
Grounding for the amps is not an issue. I have two battery bolted to the bare frame of the car and the batteries running to one another. All 0 gauge running from batteries to amps.
When I had the 2 amps strapped, the thumping happens randomly, consistently, and LOUD. I tried unplugging the RCAs and the sub remote (on the master amp and slave), the thumping does not stop. Lowering the voltage on the amp itself and the bass boost all the way down does not lower down the loudness of the thumps. Thumps will happen even if the headunit volume is 0. If I turn off my headunit (android tablet?) then the amps will turn off after a couple of seconds too.
I have the remote for the amps connected to a relay (since I have 4 amps total) taken from the headunit. If I turn off the headunit, amps turn off and the thumping obviously stops. I can turn on the headunit and the subs will be fine (will not thump) for anywhere between 30 secs to a few minutes, and then it would start thumping again. The interval between the thumps is constant but it appears to only happen when the car is running. Also, the engine RPM seems to affect the thumping; the somewhat common pattern (not always) is that when I rev pass ~1300RPM, the thumping would happen. Only sometimes when I am sitting at idle (700-800RPM) will it thump.
I have tried to unstrap the amps (each amp powering a sub). I found that ONE of the subs will thump extremely loud (the one that was set as master when strapping), which lead me to believe that the amp was at fault, so I disconnected the speaker wires from that sub, so that now only the other one is connnected. However, I noticed that there is also a slight but still very audible thump coming from the other sub. I find it hard to believe that both amps are defective from the same cause (I bought these amps from different authorized dealers at different times).
This has been an ongoing problem for MONTHS now and I have tried to troubleshoot it to no avail. If anyone has any idea. PLEASE help.
I can provide any other information or pictures if needed.
Last edited by a moderator:
