car stereo: i'm stumped

[lemkea]

okay, all my subs and amp were working fine and then the next day they are very quiet, still working, but so soft you can barley hear it. i didnt touch the wires or anything. anyone have any idea what could have happened?

 

[LOUDSHO92]

I would guess that possibly the grounds came loose and so it lost full power capability. Another possiblility but I doubt is the alternator is on its last leg.