Hi @Otellofelix 

Thanks for your post!

I believe you’re just able to hear the Sub powering it’s amplifier down to save energy - nothing to worry about. This is considered normal behaviour, as long as it is quiet. If it gets louder, please give our technical support team a call.

I hope this helps.

Dear Corry, thanks s lot for your reply.

I figured this was the reason but I needed confirmation from a technician!

Massimo

Is 2 minutes standard across all mains-powered amp/speakers, @Corry P ?

Hi @nik9669a 

The documentation says 3 minutes, and this is normal for most mains-powered speakers. Home Theatre setups will take up to 13 minutes to power their amplifiers down after the TV signal has stopped.

There’s more info on our Sonos Power Consumption While Idle help page.

Thanks @Corry P 

So, excuse me Corry P, my sub makes this noise after two minutes… there something wrong?

Thanks again.

Hi @Otellofelix 

I had presumed you were estimating 2 minutes, but I see no signs for concern in your diagnostics - as long as your Sub isn’t powering-down during playback or something, I wouldn’t worry about it too much.

I hope this helps.

Hi Corry P, thanks a lot again!

Anyhow, when a software update is available I will do it right away!