One of the coolest things about this legend was that he would happily meet with your local ham club no matter how small to share his expertise on radios, microphones, sound engineering, etc. I remember he jumped on a Zoom call with like 5 or 6 of us and we had a great time—really down to earth, solid engineer. Truly a loss. RIP.
I remember encountering Bob many years ago at the Dayton Hamvention. He was an incredibly kind individual, and I vividly recall how he crafted an adapter cable overnight for my friend's then-new radio and microphone. His generosity and expertise left a lasting impression. Rest in peace, Bob.
I didn't know Bob but I was fortunate enough to work with another legend of live sound: Tommy Linthicum.
The sound company he started with his highschool friend (National Sound) ended up doing the first 11 world tours for Rush. He pioneered "flying" PA speakers above the stage in the 1970's. Before that they were commonly just stacked on the front/sides of the stage. Later, National Sound merged with another company to form National Events, which did sound/light/staging for almost all of the major concerts and political rallies on the national mall in DC for several decades.
I have a bunch of Heil mics in my locker and they've been serving me exceptionally well over the years. PR40 and PR30 should be considered true dynamic classics.
He may have been even better known for his work in concert sound systems for the Grateful Dead, The Who, Joe Walsh, Peter Frampton, and many others.
Here is a previous HN discussion with some notes about the term "silent key":
https://news.ycombinator.com/item?id=19674170