audio volume suddenly seems awfully LOW

audio volume recently took a toll for the worst. with the same cd or music I usually play Im getting just about half of what it use to offer, also the bass is also reduced by about 50% like the mid's.

could I have of blown my mid amp / sub amp or sub itself?

btw the sub was cracklin the other day terribly but it went away for a day with reduced bass then the crackling sort of came back again.

thank you in advance!

Envy-