If they are not deaf by now, they soon will be. I ran an assholes street bikes on the dyno that was so fucking loud I had to wear ear plugs and ear muffs! It was so fucking loud, it crashed the computer in the dyno room. It was over 135db which I thing is the upper range on my sound meter.
My wife is damn near deaf, and it is not pleasant. Not for her, not for me, and not for our dog.