I don't typically use music when I teach qigong. This is a philosophy that is developing, so I may change my mind in the future, but for the time being you won't get much music in my classes.
Why is that?
Music distracts. That's what we in western culture are often looking for. With the "no pain, no gain" philosophy, exercise is difficult. We don't like that, so we look for something to distract us from our discomfort. Or boredom. That's why fitness centers play music and have cardio areas filled with TV's.
The result is the exact opposite of what we are trying to cultivate when we do qigong: mindfulness. In the typical American fitness center, we work out our bodies while letting our minds go elsewhere. When we practice qigong, part of our attention needs to be on how our body feels and where it is in space. We may focus on one area of the body (the lower back, for instance) during a visualization or on the whole thing during a progressive relaxation meditation. This allows us to become more aware of our alignment, which TCM says is a key element in maintaining health. If the body is out of alignment, qi cannot flow smoothly, resulting in sickness.
The one exception I make to this is when we are trying to regulate the breath -- that is, we want each breath to be the same length -- so that body and mind can relax. The music I use for regulating breath includes clicks at 1-second intervals and a bell every four seconds. When you hear a bell you begin to inhale, and when you hear the next bell you being to exhale. Rinse and repeat. If that feels too short, try 8- or 12-second intervals, but remember to keep the in breath and out breath the same length.
There are certainly some people who prefer to do qigong to music. And I'll agree that you may want to use it if it drowns out the chatter that would otherwise be front and center in your head. But then consider it a tool that you can eventually wean yourself away from, not as a crutch that you cannot function without.
Who out there prefers to practice without music? Who couldn't live without it?