We've talked before about our stats being lopsided --we have far fewer questions than most sites, but a VERY healthy number of visitors per day. It never before occurred to me to ask "why?" Why so many lurkers, and so few posters? What about our topic drives that combination?
On the map of Stack Exchange sites arranged by the numbers of questions (horizontal axis) and visitors (vertical axis), Music Fans site does not really stand out.
The general pattern is that science/technology sites (green and blue) have less traffic per question, and Culture/Recreation/Life/Arts sites (red and yellow) have more traffic per question. A plausible explanation is that technical sites get a lot of detailed technical questions, each of which serves a narrow audience. Non-technical sites tend to have questions of wider appeal.