Hello Dana Heston,
My ACE Group Fitness Instructor c. 2011 book says the music volume should be under 85 decibels. References in approximations are: normal conversation in quiet place is 60-70 dB, alarm clock ring two feet away is 80 dB, chainsaw is 100 dB, and a jet plane takeoff is 120 dB. OSHA says ear protection needed for workers exposed to 90 dB over eight hour period. Extended exposure to above 85 dB can damage hearing as well as the instructor’s voice. The clients should be able to hear their own voice clearly at all times.
If people care about their health, is not hearing part of the story? The owner should be responsible enough to care about the public and safety issues.
I feel for you. Motivating does not need to be loud…the group atmosphere should be more than enough to get people going, with music in the background.
I hope this helps you; I am on your side.
Is it possible to decrease the electric power to the music source? Kidding…but I think I would do that if I knew how. Hmm, I have something else to look into now…kidding…or am I?