I'm having an issue using my A95K tv as the centre speaker for an HT-A5000 sound bar - namely crackle / static.

It is not regular, certainly not constant, but crops up from time to time and is quite off-putting.

The tv is connected to the sound bar via HDMI using the e-Arc channel. The sound bar is then connected back to the tv using the 3.5mm jack cable supplied with the tv.

I have contacted Sony Support over this but their trouble-shooting advice only went as far as to suggest unplugging everything. I have read, in a number of places, static if often caused by dirt or dust which can be blown away. I have also read suggestions of using compressed air to do the job but don't know if this sounds like the very most sensible idea!! 

Has anyone else had this problem?? Can anyone advise on the dust theory or suggest anything else that might help??