Try setting the bass setting lower in the EQ settings.

Thank you. Lowering the bass to 0 and vibration still there. 

Are you sure it’s the Beam that is vibrating or is it something the Beam is sitting on or something near the Beam?

As a test, put the Beam on a towel. If that stops the noise, check to ensure that all four rubber ‘feet/bumps’ are on the bottom of the Beam, or even if I dare say it, you don’t have the Beam installed upside down. 

Thank you for the suggestions. Replayed the end titles of the Mandalorian this morning. Vibration sound goes away now when Bass is reduced to 0 or -1.  Is that normal? I was expecting no vibrations for a high cost speaker. 

Will try the towel test. It is placed right side up as  the controls are on top  

Worth a double check ;)

I’d be calling Sonos Support directly to discuss it, once you have that ‘movie’ evidence. 

The towel test has worked. Increased bass to max, played The Mandalorian. Perfect sound. No vibration or distortion.
 

so what does this mean? The Sonos needs a towel at all times?

Heh. Possible. :)

Likely really means that the vibration is between the case and the surface it is sitting on. You may want to check (I don’t own one, so I’m unsure how they’re set up) that there are four feet/bumps on the bottom of the Beam. Conversely, that the surface it is sitting on is flat, if it’s warped, it could easily cause this. 

I’ve gone to the local hardware store before to buy either rubber feet that adhere to things, I’ve also purchased felt feet with the same adhesive, which equally stop vibration. I did a quick Google search and it looks like there are several places that sell pre-made feet for a Beam. Or, you could just leave some sort of cloth, like that towel, as an inexpensive solution. 
 

The key thing is, you’ve proven that the issue isn’t inside the Beam, it’s outside, so either there is a ‘foot’ (if there are such a thing on a Beam) missing, or the surface the Beam is on is slightly warped, and not as flat as the Beam is expecting.