ON a recent humid Sunday, 26 members of the Harmonium Choral Society shuffled into Grace Episcopal Church here and dropped their belongings among the pews. As they stood in a scattered group, they locked gazes, stretched their arms skyward and hissed at one another.
That was a warm-up for a three-hour session that would culminate in the recording of three minutes of original music, created on the spot, to be woven into the Shakespeare Theater of New Jersey’s production of “Hamlet,” which is running in Madison through Oct. 11. Music previously recorded by the group would be used at other points in the play.
Bonnie J. Monte, the Shakespeare Theater’s artistic director, approached Harmonium’s director, Anne Matlack, about a collaboration after she heard the singers at a First Night event in Morristown last year.