Do you hear the sound from all sources (including 5.1 and Dolby Atmos) or is it just with a Stereo PCM source? Other than the “raspy” sound, does the surround audio sound normal from the Era 300s?

It doesn’t make any difference if it’s 5.1 or Atmos. The only time I don’t hear it is when I turn the surrounds off. If you have surround sound like an airplane flying around you really don’t hear it but when that passes then I hear it again. I might add that it is like a pulsating sound. I don’t know if I’m making any sense or not but it’s the best I can do right now. Thanks Guitarsuperstar!

If you move the Era 300s to a completely different spot and plug them in to a different outlet, do you still hear the sound?

I’ll have to try that. May take me awhile as I don’t have a lot of outlet options.

Guitarsuperstar I was able to move about 3’ and lower but I get the same result.

Just to test, move the speaker to a completely different area or room and plug it into a different outlet.

Finally caught some breathing room. So I moved one ERA300 to a different room with the same results.

You should contact Sonos Support.

Ok, I will do that. Always appreciate your help!

Guitarsuperstar! I contacted Sonos as you suggested. They had me enable wireless on my ARC. They said when set to wired it would not communicate with the satellites. Did that and it fixed the problem!  Thanks again!