Okay, sometimes when I turn on my car there is a VERY FREAKING LOUD RUMBLING sound that comes from my subs. It is annoying and makes me look like an idiot. Plus, when it does happen, my subs sound like crap for the rest of the drive. When it doesn't happen my subs sound AWESOME.

I have a 180watt RMS MTX Amp, and two 12" kicker subs in a ported memphis box.

Sound's like the amp isn't grounded good. Make sure it's metal to metal and tight.

yeah check your amp ground

Took the dremel both of the grounds for the 4 channel amp (the one I got from thehardknoxlife), the sub amp is ground fine (well it worked great before I put in the amp for the speakers).

It still does it damnit! I hate this damn noise, it is loud as FAWK!

So do you leave the radio turned on and up loud? What is different when it DOES happen? Give us specifics here....

Just because the ground is attached does NOT mean it is OK. Take a long piece of ground wire, run it directly to the battery temporarily (eliminating the current ground) and see if that makes a difference.

Nothing changes between when it happens and when it does! That is what is so weird.... Volume is always at 10 when I turn the car off and on, that is my baseline for driving. I may try grounding it like that....

Next time this happens, jump out and unplug the RCAs at the amp... if the sound goes away, then your RCAs are picking up noise from some electrical component maybe *** they're either low quality, or damaged during installation.

What kind of H/U are you using? Try regounding it also especially if it's in a b13. I had trouble tracking down a noise in mine once and this solved my problem.

Yes it's in a B13, and it is a Pioneer HU. I reached over and wiggled the RCA's while it was rumbling (the speaker amp is under the passenger seat) and it seemed to change it a little. I'm gonna look at it later.

What model of pioneer? I thought it was coming from the sub's? It could be faulty RCA outputs on the H/U, those Pioneers have been know to have bad RCAs. I don't think any of them after 2005 has had that problem. There is a fix if that's the case. You have to manual ground the RCAs. There is a write up on this somewhere let me know and I'll try and find it if all else fails.

It is coming from the subs. The HU outputs go to the speaker amp inputs, and the speaker amp outputs go to the sub amp inputs.

The stereo isn't the nicest, it's a DEH-1500 I believe.

Ah I see. Make sure you use good rcas. Have you tried running the rcas straight to the sub amp? If your not getting noise throught the front stage then it's not the (Pioneer) ground loop issue I mention earlier. It seems to me that its a ground issue or cheap rcas.It is coming from the subs. The HU outputs go to the speaker amp inputs, and the speaker amp outputs go to the sub amp inputs.

The stereo isn't the nicest, it's a DEH-1500 I believe.

The RCA's are singles from Bestbuy that are supposed to be for home audio. If I bypass the speaker amp and just connect the sub amp I will only hear the subs right?

Just spend $20 and get some RCAs that are made for automotive sound. There are countless sources of noise that need to be shielded properly against.

The RCA's are singles from Bestbuy that are supposed to be for home audio. If I bypass the speaker amp and just connect the sub amp I will only hear the subs right?
Correct. But if the noise goes away, then you have a better idea of where the real problem is.