Warm-up time is a great time to practice ensemble roles, focus on rhythmic feel, and experiment with small rhythmic and melodic ideas. It's an important part of coming together as an ensemble and getting everyone's head in the game. Below is a short list of warm-up ideas. You're sure to come up with your own!
1. Choose a major, minor, dorian, mixolydian, or blues scale related to a tune you're studying.
Play it in ascending and/or descending quarter notes while the drummer establishes the appropriate feel (swung or straight)
Play it in pairs of 8th notes, ascending and/or descending, in the appropriate feel (swung or straight)
Play it in single 8th notes, ascending and/or descending, in the appropriate feel (swung or straight)
Perform any of the previous exercises, but with the guitar/piano player comping a matching chord and the bass player outlining the same chord
2. Choose the harmonic form to a tune you're working on.
Suggest a rhythmic pattern (play or sing it). Play it over the harmonic form using root notes or other chord tones (this is also a good way to introduce background figures). For longer harmonic forms, consider choosing one section for the warm-up.
Play the same exercise above, but have a student suggest the rhythmic pattern (play or sing it).
Play the same exercise, but everyone
Play the same exercise, but with a melodic motive (this is also a good way to introduce melodic sequences).
3. Choose a chord from a tune you're studying.
Vamp the chord (guitar/piano player comps, bass player outlines chord, drummer establishes rhythmic feel). Encourage horn players to experiment to come up with a riff (singing or playing). Choose one riff, or let one emerge organically. Keep vamping the chord while the one player performs the riff; others join in as they acquire the riff by ear.
To include the rhythm section in the riffing: (1) rotate relieving rhythm section players of their ensemble roles so that they can join in on a horn player's riff, or (2) specifically start with a rhythm section player's riff.