I have installed 2 Ifi systems and both have exactly the same problem.
Both systems have sony DVD players audio outs running into the sub. When playing a CD the speakers pop and crackle like mad, turning up the ifi volume does not affect the level of the pops and cracks.
It does this on both systems, only when listening to a cd. When listening to an I-pod the sound is fine, also connecting a TV's audio out into the sub did not have any pops and cracks on the speakers.
I think the line output on the DVD players are maybe too high for the I-Fi, as i tried a different brand of DVD as a test it it too sounded fine.
Any suggestions?.
Thanks