@deehee47,

Can you perhaps give some examples of how and when the Arc reduces its volume-level, otherwise without these things, it’s likely not possible to even begin answering your post without some further detail.

It shouldn’t, unless you’re using some sort of voice command, and it’s temporarily ‘ducking’. Have you submitted a system diagnostic within 10 minutes of experiencing this problem, and called  Sonos Support to discuss it?

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.

If I’m watching tv and the Sonos Arc is being used, if use another Sonos in another round, the volume is temporarily ducking. It happens every time I use Alexa. 

If I’m watching tv and the Sonos Arc is being used, if I  use another Sonos in another room, the volume starts  temporarily ducking. It happens every time I use Alexa. 

Try removing the Sonos Arc from the Alexa ‘enabled’ group(s) in the Amazon Alexa App and see if that resolves your issue.

Thank you. It worked. I appreciate it.