Noise coming from subwoofers and centre channel

Highly recommend buying a digital filter for your Cable wire leading into your cable box. Make sure you get one that's male female so you can just avoid using another wire. You can get them for about 10 to 20 bucks on Amazon. There was a recommendation made earlier for $75 isolator but that was crazy. @jetter .

Maybe the recommendation was for a really great isolator but the one I bought solved 90% of the problem. And my cable wiring to my house is grounded. Another problem I had was I have a tube amplifier and that inherently picked up a lot of hum versus solid state when I had one which had no hum.

You could always just buy a dog and forget about everything else.

OP: Well my recommendation of an HDMI isolator is still the best way to go, but another HDMI cable may help and be a cheap solution.

It would really only help if the ground was significantly better... so for sure dont' spend money on boutique cables.  Buy an affordable one that's as short as possible but looks well made.

For the HDMI isolator, how it would works. My HDMI is connected between my projector and processus and then, it to my AVR.

Where do we connect this isolator?

Thanks

The HDMI isolator seems to be very expensive more than 1000 $ CAD.

Also, i hope those isolator are compatible with Dolby atmos, HDR, 4K etc....

Could something like this possibly solve the problem?

FIBBR FIBBR Câble à fibre optique HDMI 8K 48 Gbit/s ultra haut débit 8 K 60 Hz 4 K 120 Hz 144 Hz HDR/eARC dynamique compatible avec PS5, Xbox Series X, PC, TV (5 m) : Amazon.ca: Électronique