Hi @Bill Kent 

Welcome to the Sonos Community!

I was able to find a couple of other topics on this subject: 

The second is somewhat lengthy, but the first has a good suggested solution:

Have you done TruePlay on your Arc? If so, redoing it may fix the problem. Please try TruePlay-ing from your intended listening location (like your sofa) only - just move your arm around rather than traversing the room.

You can also try turning TruePlay off altogether.

If you haven’t done TruePlay, or if it makes no difference, I recommend you get in touch with our technical support team directly.

Update: Issue Resolved (My Stupidity)

For anyone using an older iPad for tuning, the mic is in the top of the device, not the bottom!  Once I ran trueplay leaving the iPad in its normal position, the sound is absolutely perfect.  NOTE FOR SONOS, suggest you change your trueplay video instructions which recommend you flip your device… that is not always correct.  In my case, doing so put the mic facing the floor, which created all of my sound issues!

LOVE THE SOUND NOW!

Glad to hear you got it sorted out! Enjoy!