Noise coming from subwoofers and centre channel

One thought — you didn’t mention if you’re using a power conditioner/surge protector, which I would hope you are given the cost of your system.  If so obviously the conditioner would be plugged into the wall with a 3-prong plug so wondering if then using a cheater plug on the projector is a non issue?  If you’re not using a power conditioner that’s definitely something to address, and depending on how its designed may also help alleviate your noise issue without a cheater plug.  Just some further thoughts FWIW and glad you’ve at least identified the culprit and gotten rid of the noise — that’s gotta be a huge relief!

Hi good afternoon,

I only use a powerbar. Here a link of my model. All my power cable are from Bis audio ( 3prong plug)

BIS Audio PowerBIS Maestro A/C Power Bar + AC20WG A/C Power Cord Review – NOVO Audio and Technology Magazine

Thank you for your findings. Indeed, I am happy to have made the discovery but I do not want to put my system and our security at risk....with the cheater plug...

Not quite sure where you are in your investigation.

If your system is connected to cable tv I will share I had a pretty obvious hum/buzz. 

What solved my problem entirely was connecting the following Jensen VRD-1FF IsoMax CATV Digital RF Isolator between my xfinity coax and the xfinity cable box needed to run my TV.

Jensen Iso-Max VRD-1FF 75 Ohm Inline Digital CATV Isolator Hum Eliminator (parts-express.com)

Note that the coax from outside is first split and one leg goes to the TV and the other to my modem/router.  This was only needed on the coax leg going to the xfinity cable box.

Hi,

No my system is not connected to any TV cable.

Thanks for sharing.

I only use a powerbar...I am happy to have made the discovery but I do not want to put my system and our security at risk....with the cheater plug...

But, your entire system already is at risk as you’ve got no surge protection and there are many here who’ve told tales of losing expensive equipment plugged into the wall.  I have a vey transparent Wiremold power strip, and when I wanted to add power conditioning and surge suppression I just got this and plugged my power strip into it and my whole system was protected on the relative cheap.  I still question if your power strip is plugged in with a 3-prong plug if the cheater plug makes any difference — I don’t know the answer but maybe someone like @erik_squires or someone else does.

https://www.usaudiomart.com/details/650064731-audience-adept-response-ar1p-power-conditioner/

FWIW.