Does the buzzing/hissing happen with just TV audio or with streaming music too?

Have you tried unplugging the speakers from power for a couple of minutes?

@GuitarSuperstar thank you for taking the time to reply and your feedback.

In reply to your questions:

• The faint hiss (white noise) occurs for all contents whilst playing, which includes TV audio and streaming music.
• I have followed your advice and unplugged the power sockets from all the speakers for at least 10 mins and the issue still present afterwards.

It is the same issue as describe by other users in this thread

https://en.community.sonos.com/home-theater-228993/sl-one-rears-hissing-6848819

I have just bought the two refurbished One SL, which are setup as surround rear speakers.

Due to being very close to the surround speakers, I can hear the faint hiss of white noise from both One SL speakers, when I put my ear next to them.

The faint hiss is present when content is playing, but after 5 mins or so when the content/TV is stopped/powered off, the hissing completely stops.

I has hoping staff on the forum would be able to review the diagnostic log, and advise if there’s anything that stands out as being abnormal in it.  If there is any other advice/guidance available, then that would be appreciated.

Thank you.