Dominick Argento was the first composer commissioned by the then-Plymouth Music Series choir, in 1973. Now called Vocalessence, the choir has since commissioned numerous works from Argento — the latest to celebrate the choir’s 40th anniversary. The world premiere of The Choirmasters Burial, features more than 500 singers from seven Twin Cities choirs — Kantorei, Magnum Chorum, Minnesota Chorale, National Lutheran Choir, The Singers, Twin Cities Gay Men’s Chorus and Vocalessence. 3-Minute Egg went to Orchestra Hall for Saturday’s rehearsal. The concert was Sunday.