You want to create a lively, alerting atmosphere in your pre-dawn class. However, extended exposure to sound levels of 85-90 decibels or greater may eventually damage hearing, so it's not an option to just "crank it up". You choose to raise the bass but lower the treble because:

Question

Quizplus · Accepted Answer

Because lower frequency (bass) sounds are less damaging to hearing than higher frequency (treble) sounds, instructors looking for a lively atmosphere may choose to raise the bass and lower the treble, if sound levels are maintained below 85-90 decibels. Another effect of raising the base may be more active participation in the class. Since the bass often carries the dominant beat, an elevated base may increase alertness and arousal through a process known as "entrainment."

You Want to Create a Lively, Alerting Atmosphere in Your