What dancers and callers understand as “a measure” or “a beat” is not
necessarily the same as what professional musicians will understand,
depending on how the sheet music was written.
(My wife is a classically trained clarinetist who can also play violin and
fiddles a little; she has gotten used to my terminology, but we still have
miscommunications occasionally.)
I strongly second the advice of communicating the concept of potatoes and
practicing exactly how long you expect the band to play before you start
calling, and how to signal the end of tunes. The advantage you do have on
that particular front (assuming these are classical musicians) is that they
are used to watching a conductor for gestures.
They may have difficulty setting a good starting pace for tunes. I’d tell
them to be careful with recordings as those frequently are paced
differently and are flourished for listening. One of the finest fiddlers I
know once recorded a 9 minute track for me with the preface that it would
be great for dancing, but not much to listen to.
I will ask my significant other if she has other advice.
Neal Schlein
Librarian, MSLIS