Panasonic 5.1 Home Theatre’s subwoofer making rattling/cracking and popping sounds

[deaduma1r]

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 AUX, even if the other end isn’t connected to any thing. No such noise is made when it is muted i.e it increases with the volume from the Theatre or TV/mobie phone. Secondly, on low volumes, it intermittently drops bass and makes popping noise before and after dropping the bass.
I do use a Havit Ground Loop Isolator. Tried removing that as well.
Using 3-legged switch for the receiver on a completely separate electrical switch.
Tried moving the speakers and the sub away from each other and the tv but no luck.
Any solutions?

 

[hang-the-9]

Since you recently bought it I would contact Panasonic support since they can handle a warranty return if needed.

 

[jsmithepa]

Not normal. Return.

 

[deaduma1r]

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 RCAs individually on both Red and White ports of the receiver and there is no such sound on any of the 5 speakers. I guess that makes a subwoofer faulty.