break in sound

Is this whilst playing TV audio, or whilst playing music to your Sonos system?

Also what TV is connected to the Arc and does that TV have anything else connected to its HDMI Ports? 

Are you controlling the volume using HDMI-CEC or Infrared?

Thanks for your reply, it’s whilst playing TV audio.

TV is a Samsung QLED and I do have freeview, fire stick and blu-ray attached to other HDMI ports

controlling volume with fire stick remote

So is infrared switched off on the Arc and is it a case you are using HDMI-CEC (via Fire TV) to control the TV volume or are you using infrared? 

Also, is there a reason you are not using your TV remote and HDMI-CEC to control the volume instead? - have you tried that to see if it fixes your issue?

Perhaps less importantly… on fire TV there is an option in the sound settings to switch off the Navigation Sounds - are those switched off?

I haven’t tried that but I will. 
I tend to use the fire stick as it has the quick access Netflix, Amazon Prime buttons, I’ll get back to you once I’ve tried that.

thanks for help