I’ve had a Sonos Beam / Sonos One(x2) system for about 3 years. Everything has been fine until recently when every 15 minutes or so a high frequency noise will emit from the left rear speaker for about 5 seconds. It is very irritating. I have unplugged it and plugged it back in with no improvement. 

Someone posted an identical issue 4 years ago (now closed) with no resolution. Per responses to that, I do not have an extension cord with an on/off switch, but did swap it out anyway. I am in Spain, so it’s 220v. 

Should I do a total reset of the speaker?

DISREGARD. I UNPLUGGED THE SPEAKER AND I NOW THINK IT IS COMING FROM MY COMPUTER.