Loud subwoofer popping noise

4 possibilities:
1) ground loop or open connection on input.
2) close proximity to a CFL, or other flourescent fixture.
3) bad filter caps in the sub.
4) bad coax to the sub.

in any event, check wire routing. You can also track down the noise sources by using a portable AM radio tuned off station. it will pick all manner of RF noise around the house. Light dimmers are notorius noise makers.

The symptom sounds like an open signal shield somewhere and the cable is acting like an antenna for airborne electrical noise.

Disconnect the RCA cable at the sub. Is it still humming? NO? Problem is external to it. YES? Internal. Broken ground somewhere.

Recheck all connections making sure to twist the RCA head as you install it so oxides will be worn off.

Consider what may have changed in the environment regarding electrical devices, motors, magnetic sources. Ensure signal and speaker wires as ar not running are as non-parallel to any power cords as practicable.

Sounds like the sub is blown. Swap the two subs and see if the sound comes from the other sub in the original location as well. If not, then you have a bad sub. If the bad sound happens with both subs then you need to look at wiring and the Amp.

well, hopefully the amplifier was wired correctly. But either way there are so many factors that can cause this problem... But the biggest one is the amplifier must have been sending some distortion to your subwoofers which a subwoofer can take a certain level of distortion and be fine but too much will blow any subwoofer even the highest of high end subs at a high volume... when your subs hit the point of blowing they will tend to just blow out one at a time... they don't just pop both right away. I'd say get the sub that isn't blown off off of the amp before it blows too... distortion is clipping most of the time... when you destroy the subs it will eventually work it's way to the next component in the system which is your amp and then you will be out an amplifier and subs. save yourself the headache.......

had the same problem, so I installed a radio shack ground loop isolator and fixed the problem, it has 2 rca plug inputs and 2 rca outputs, goes in-between the sub and the input cables of your system to the sub...that's if your using the rca inputs..

Well, I have the same problem and I would think it has something to do with the RCA-connections. If I power up my head unit while I have my main fuse for the amp's removed and then replace the fuse as the head unit is already playing music (thus putting out a current through the RCA-connections) it works just fine. But if I just power up my stereo with the fuse in, my subs go all crazy. I guess it has something to do with disruptions in the rca cable. Maybe they are drawn too close to some power cables or speaker cables? Good luck!

The only way to Correctly do this is to Run an External Amp for your Subs. If you continuously run the Subs off of the Factory Amp It will Ruin the Subs and the Amp Eventually. This way you can still Connect the Rear speakers as they need to be. Please Rate my solution, I need all the Help that I can Get! Thanks!

Well as I see from the owner manual for this device the sub is active one and my opinion is that electric is your problem.The power of the sub and main unit must be on the same phase otherwise you'll hear brrrrr or frequency of your main unit power supply on the sub.Thats why sound changes when you open or close the door.Take one power distribution cord (get power for bought devices from the same place) and connect main unit and the sub on it and then try.I hope that this will help you

the ground may not be coming from your stereo it should be coming from a loose wire under the hood. Do u have the factory radio? that might be it if u do

Check all the wiring. It could be a loose connection since it's intermitent. Really pay attention to the power cable, both the end for the amp and the one that's going to the battery cable.