Sketching during a rehearsal session of my brother's cover band

My brother Matt asked me to come and sketch the members of the band during a rehearsal session.
Interesting and difficult at the time... Alex, the guitar player, and Matt, on the drums, are moving all the time. Jacques, at the bass, and Jérôme, the singer, are more static than on stage. I prefer the slow pieces and breaks to do my job!
Arnaud