That is what I worry about with the volume on my mp3 player. I don't like it too loud. Got to protect that hearing! This coming from someone who has seen the loudest concerts in the world in my teens and early 20's! Kiss was the loudest. My ears rang for 3 straight days. Not good! I remember their slogan was, "If it's too loud, you're too old". I didn't realize they really meant that until I saw them. I guess I was too old in my early 20's. Ha ha! Most concerts were metal and hard rock. I have seen others like KC and the Sunshine Band, MC Hammer, Vanilla Ice and a few others that didn't blast it that loud. =)
Back to the music that motivates us. Like I mentioned my file is too small so I switch sometimes from Beatles then take that off and put on another set I have. The other set of music varies from hip hop, country, opera (only 1 song, Time to Say Goodbye, Bocelli), disco, rock, etc. I love all kinds of music. I don't listen to a lot of country music but I am a die hard fan of Patsy Cline, Queen of Country!
My mom said her workout is not as good without music either. I guess I just like to change it up sometimes and not listen to anything. Most of the time I need music. Depends on my mood. =)
I have seen Spin Cycle classes at my gym. That is one heck of a workout! I should try it sometime.