Like in the manual, where they have printed this:

?

And later, as part of Important safety information:

7. Do not block any ventilation openings. Install in accordance with the manufacturer’s instructions.

8. Do not install near any heat sources such as radiators, heat registers, stoves, or other apparatus that produce heat.

Perhaps you would prefer if the box bore a great red label: 'WARNING: LARK'S VOMIT!!!'

The laws of physics always prevail. If you inject more energy into the space than can leak out, the temperature will rise. You’ll need to figure out a way to ventilate the cabinet.

Thanks Bruce. Operating in that range and no other equipment around. Must have been in closed environment.

Thanks all. My “Professional” installer did the work about 3 months ago and it is just now having these issues with no change in the environment. Temp in room is 72 degrees F so only change I can think of is turning on all 4 zones at once versus 1 or 2 zones.

I’ve spent a few dollars and effort myself in order to open up / force air through closed cabinets. Lots of ‘unseen’ hole cuts into IKEA cabinetry , and a few computer (USB powered) fans in order to get cool air to circulate. For some reason, most cabinet makers don’t seem to think about electronics which, by definition, create heat. Never understood that…but mostly because that’s what I’ve traditionally used cabinetry for, holding electronics. 

And yes, likely using all four simultaneously increased the amount of heat generated. I’d be complaining to your installer, they should have known that electronics needs more circulation of cool air. 

Just sent the installer an email. Thanks again.

Decorators hate technology and attempt to bury it as much as possible. Meanwhile the cabinet makers take pride in designing the cabinet to fit the components with glove like precision — squeezing out all of the “wasted” airspace. Without any means of circulating air to remove heat, the components will overheat and realize a much shorter lifespan than expected.

SONOS components are well protected and, as you’ve discovered, they’ll take action if necessary to protect themselves from eminent danger. That said, it’s not a good idea to continually operate them at one degree below the shutdown threshold. A very significant cause of component failure is the depth of temperature cycles. A cycle begins at room temperature, continues to the operating temperature, and ends at return to room temperature. Components are rated for xx cycles of yy degrees. As yy increases, xx diminishes rapidly.

A couple shutdowns are not too significant, just accept them as a warning, prodding you to take action and prevent future ‘events’.