What possibly can cause these 2 issues?
Update: I just disconnected the RCAs completely from the wiring and it was gone. Putting them back brings the rattling/cracking back.
Still no solution for the bass drop at low volume.
Update 2: I disconnected the subwoofer and tried both Red and White...
I recently bought Panasonic SC-XH166 5.1 Home Theatre as it was on sale. https://www.panasonic.com/middleeast/en/consumer/home-entertainment/audio/home-theater-systems/sc-xh166.html
It has a subwoofer (model no. SB-HW3010) connected to it which makes rattling/cracking noise intermittently on...