[Callers] Using music in the pre-dance lesson

I'd like to hear from any of you who can share experience or advice about making use of music during the introductory lesson (a/k/a "new dancers' orientation", "beginners' workshop", etc.) that often precedes a regularly scheduled contradance. What source of music do you use? (Recorded music played on a device that you control? Live music played by a musician assisting with the lesson? Music that you yourself can play on some instrument while leading the session? Your own singing of song lyrics, nonsense syllables like "la la la", or dance calls? Music that may happen to be coming from the evening's band doing their sound check at the other end of the hall? ..) How--in as much detail as you care to supply--do you use that music in your teaching? What do you think/hope your use of music contributes to the effectiveness or fun of the lesson? I tossed out a few ideas on this topic, with much uncertainty about which ones were any good, in a message I sent on September 2 in the "Brain Dead - Need Suggestions" thread. I'm re-raising the topic here under a more descriptive Subject line in hope of getting responses from people who can offer comments based on actual experience. Thanks. --Jim