Before the dance last night the band asked if they could play an unusual old-time tune. I gave it a listen and after a while I asked how the B part went. "But this is the B part!" They pointed out that the A starts on a I chord while the B starts on a IV and so the change should have been clear. I felt embarrassed as a musician for not hearing it, but as a caller I treat my confusion as a signal: if I can't follow it, the dancers won't be able to either.

This isn't a firm rule: there are things that won't confuse me but do confuse the dancers. This is partly because I'm a musician and partly because I'm not dancing, but it's mostly worked well for me. If I find myself losing my place in the music I find it again by watching the dancers and listening, and then I start calling a bit. Just a few calls in the most confusing places, but the goal is to keep the dancers from drifting relative to the music. I don't tell the band to change tunes unless it's really bad, but (if I remember) I'll tell them afterwards that I don't think that tune is a great fit.

(If I have a chance to listen to a tune in advance to see if it's suitable, I don't count it out. If I'm counting I won't get lost as easily, which weakens the signal. You often want to confirm that the tune is square, however, so you need some way to tell. I do this by tapping my hand on my stomach: four taps in one place then four in another, with four places in an И-pattern. If I repeat that four times and the music comes around, the tune is 64 beats.)