Biergarten opens at noon, and the band usually plays at 1:15, 2:15, 3:15, 4:45, 5:55, 7:00, and 8:05 pm.
Not sure how much they deviate from that schedule, but I do know this past Sat (NYE) the band came out sooner than 5:55 pm to celebrate/countdown the German New Year @ 6 pm. The dance floor is also back open.