random intermittent audio on iMac

This is a brand new iMac and it works beautifully and as expected EXCEPT that it will often play random AND intermittent audio. It could be music or an advertisement, literally anything.

I have gone through the process of looking at each open browser window (Safari and Firefox) finding nothing. Next logical step was to close all the running programs (while this random intermittent audio was happening).

I even tried checking Activity Monitor to see what might be happening but, using all of the search terms i could think of related to 'audio' i found nothing.

Needless to say, this is hugely frustrating when i am in a Zoom meeting with a client.

Any help with this would be most appreciated. My computer details are below.

...john...

Model Name: iMac

  Model Identifier: iMac20,2

  Processor Name: 8-Core Intel Core i7

  Processor Speed: 3.8 GHz

  Number of Processors: 1

  Total Number of Cores: 8

  L2 Cache (per Core): 256 KB

  L3 Cache: 16 MB

  Hyper-Threading Technology: Enabled

  Memory: 32 GB

  Boot ROM Version: 1554.80.3.0.0 (iBridge: 18.16.14346.0.0,0)

  Serial Number (system): H4***N7C

  Activation Lock Status: Disabled

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