i have an aftermarket system, with a powered sub. i notice that when the engine cooling fan turns on and off, the sub would boom.

1) should i install a cap
2) should i redo the grounding for the powered sub
3) should i put in grounding kit

ideally its probably all 3 and some more, but i am looking for the least amount of work and just getting rid of the annoying boom.

or is it simply a poor quality power sub (it does boom slightly when it powers on)

 

sounds like it's picking up EMI/RFI noise and that's filtering into the sub. You might want to add a noise filter to the power of the amplifier.

 

noise filters are temp problem fixers. Dont do it. Find the real source of the problem.

 

its a ground issue on the amp when the cars elec system goes under load

 

multiple choice guys, not question and answer type.

 

I'd go with re-doing the grounding for the amp. Also, check the signal wires (dont know if you're using speaker level or rca/line level) for signal bleeding. Could be picking up noise through that. Can re-route them from where they are, can be picking up noise through them

(sorry for the above deletion, didn't do that right, lol)

 

What exactly does that mean? What's the "boom" sound like, and does it always sound the same? Does the "boom" always happen at the same volume, or is it sometimes louder/softer?

Does it always do it, and does it happen every time the fans turn on AND off? Does it only happen when the sound system is turned on and playing music, turned on but playing nothing, or even happen when the HU is off?

The cause needs to be determined before a potential solution can be suggested, otherwise it's all just speculation.

 

I have a powered sub, so its turned on when the stereo turns on. and off when its off.

the boom depends on the music level. I notice it more often on a hot day when the AC is working and the volume is up.

 

its a ground issue