Interesting article.
My observation: 22 seconds after the Bong, my inherited 21.5" iMac 10.1 gives a loud "Pop".
My previous 24" iMac and 2014 miniMac have only Bonged.
All other audio is just fine with it.
Suggestions?
21.5 iMac, Late 2009, s/n: W8950YY95PC
3.08GHz, Core2 Duo
16GB 1067MHz DDR3,
NVidia GeForce 9400 w/256MB
MacOS 10.13.6