The question of the week in the vocal jazz educator group was, when should you start rehearsing on system?
It’s a different answer for my two ensembles.
Shades of Blue, the vocal jazz ensemble I direct at Grand Rapids Community College, rehearses once a week for two hours. We rehearse on mic starting from the very first rehearsal. I think it’s important that they get comfortable learning to sing, balance, and hear through the system. (I also know they practice off system in their weekly sectionals, and in their personal practice.)
The Rockford Aces, the high school TTBB ensemble I direct, sings a wide variety of repertoire, from Renaissance to contemporary pop. I like to make the first third of the year about really quality ensemble singing, and the second third is devoted in significant part to preparing classical repertoire for festivals. The last third of the year, we rehearse many weeks on system. It takes that whole last third for the ensemble to adapt their sound to microphones, and it’s a thrilling process to hear them learn how to blend on mics in real time over the first two weeks on system.
Other directors alternate rehearsals, or do 2:1 in their 3x weekly schedule. If I saw my ensembles every day, it might be system Monday-Wednesday-Friday or some other strategy. But for extracurricular, once-a-week ensembles, I think it needs to be most or every time that you meet to work on microphone-appropriate repertoire.