no idea whats happening with sub amp

so i've had my set up for a while and i got a new box so today i mountned the amp on op of the and it was playing fine for a while, then all of the sudden the subs just start hitting super loud and if i turn it down or off it's still just pounding a single note. And i have to pull over and turn off my car for it to stop. I have no idea what's wrong please help. MikeHello.

Vibration is the Enemy.  I would not have mounted the amp to the box.  Do you have a Pioneer radio?  Does your radio have Pre-amp outputs for the sub amp, or are you using a Line Out Converter?  Are you driving a Honda?

This has happened to me before.  My senario was: Playing song and as I increased the volume, the subs just went crazy.  Started to play just one note like you said. If I turned the volume down, it didnt make a difference. I had to shut the stereo off.  The problem was that my headunit was feeding my eq strictly high frequencies.  I didnt turn off the high pass filter like I should have and as soon as I set my stereo settings to full range which fed my eq and inturn feed my amp for the subs, the problem no longer existed.  You could also be clipping your amp.  Are your gains set correctly?

funny you ask if i have a pioneer radio because i had stock, then i was installing a pioneer deck and had it playing then pulled it out to add on USB plug in and the one of the power wires on back of deck ripped out, so now i cant hook it up so i just put back in my stock cd player. My system sounds really good with my stock cd player and i've always used it. I like it because no one would think i have couple stacks worth of doodie in the trunk. And it sounds good and its nice and clean. Anyways i'm runnin stock, i did move the amp so it could be the ground connection, although i did unhook from amp then reconnected after i moved it. So could it be my EQ settings an hi and lo filters and other settings i have a 1500/2 MTX thunder so there's so many settings. But it started happening after i moved the amp and basically reinstalled my stock deck...i dont know whats the problem.Hello.