Those of you old-enough to know, what did the bands of the 1960's and '70's & into the '80's all-use on-stage for their shows? Banks of Altec-Lansing
Voice of the Theater speakers.
When someone who knew what he was doing ran the soundboard at the concert, you would have a silken sound that was loud, but not punishing in a 120 dB fashion. I think that the equation was that bands who could afford the best equipment would set their road crews up w/the best you could get-speakers, amplifiers, mics for the performers, and the end result was even the huge interiors of sports amphitheaters could sound decent, which was a hard thing to do, given the limitations of design, furnishings and volume. Halls designed for acoustics didn't seat enough paying patrons to allow the arena-rock bands at the peak of their careers to play in those places. After time there was some movement to return to a better acoustic environment and those shows got people willing to pay more for better acoustics and smaller capacities. A more-intimate seating arrangement, not in the five-figure seating capacity area, proved to be a good move for the bands because they were able to enjoy themselves more than in a 20,000 seat capacity stadium.
A good exhaust (to me) is one which combines performance and a limitation on loudness so you can use the upper rev ranges in a populated area w/o destroying everyones' hearing momentarily as you roar-by at 8,000 rpm.
That's what drove me to reduce the UFO sound via my mod to a point where babies won't cry, mothers won't give me dirty looks, and cops won't automatically target-fixate via excessive noise presence.
Bonus points if you know who the band is! (no 'properties' search!) And, who's the guy w/the hat next-to the guy at the mic?