If an opening number is traditional for a group’s long-form musical show, no mystery there. Later, however, you’ll be listening for opportunities to effectively encourage a musical number, and another and another and another.
When do you “cue a song?” Well, anytime a character experiences a moment of great emotional significance is a good time for them to sing, particularly if it seems to be the climax of a scene.
Also listen for emphatic statements that can be expanded upon in song, for example, “You and me are the sleaziest cops in town,” or “There’s a lotta ways to make money in New York, my friend!” And here’s one more: “Come on everybody, we’re gonna throw the best barbecue ever!” You’re looking for bold proclamations of feelings and points of view – perfect moments for actors to exploit by singing.
If you’re like me, you play various “incidental music” during a long-form musical that isn’t intended to cue a song. I have contrasting approaches to “underscoring” and “cueing a song” for the sake of clarity. My underscore is subtle, often out of tempo, often dissonant, and doesn’t much like an invitation to sing. Conversely, my “song cue” will stride aggressively into the air, in tempo, and sound distinctly song-intro-like to both actors and audience. Most often it’s some flavor of a vamp.
When you make that committed first move, it can contain this collection of info for an actor’s ears – style, tempo, groove/feel, key signature. A vamp is always a good idea because it presents a conveniently “revolving door” for the singer. Some actors can work well with less informative musical offers, like an arpeggio or even a bell tone. These are fun, and require expert leadership from the singer as we literally discover the song together.
On occasion a singer will launch from silence into a musical number, in which case you must find them – locate the apparent key, and feel the tempo that seems evident. I don’t have perfect pitch, but it works for me to use relative pitch…I lightly strike any single note as the singer is singing, compare it to what I’m hearing, then begin to sneak in accompaniment that reflects what is apparent rhythmically and melodically.