In a typical choral performance, singers file onto a stage, climb risers, and arrange themselves by sections; soprano, tenor, bass, and alto singers stand shoulder to shoulder, primed to create collectively a big, beautiful sound known and loved by many. But it’s a tradition that requires two elements that are non-negotiable during the coronavirus pandemic: large gatherings and close proximity to other people. Following a trend directly related to performance cancellations these days, the North Carolina Master Chorale is going virtual.