I was mixing sound for a church Christmas production consisting of a choir with 94 voices, a 20 voice children's choir, two flutists, a double bass, percussion, viola, harp, piano and a pipe organ.
I had 16 mics and powered subwoofers to augment the church's 70 volt sound system. I had two SM81s on the main choir and one SM81 with the children's choir standing on a riser that doubled as a platform for the double bass and the viola. The riser was below the main choir seats. I used an SM57 underneath the Steinway baby grand (because the pianist wouldn't allow mics on top-she was afraid of being too loud even though the top was taken off so the choir could hear the piano!). The built-in system has 70-volt speakers in overhead rows; any mic pointing straight up immediately starts feeding back. The house system doesn't have any sub-woofers or console and only four built-in mic jacks. I was using my 40-channel console with the typical processors and racks. The mono output from the console was plugged into a 30-db pad, which in turn was plugged into a mic jack of the house system.
The previous week, I heard the same viola and the same choir performing in the same building. The viola was the lead instrument and did very well until the end, when the music called for a note high up on the fret board and the musician just couldn't find and hold it.
So I was watching to see what would happen during the Christmas production. With a full house of nearly 2,000 people, the music started. Things went well through the production. The director then announced an encore, which was the piece I'd heard the week before. Just as before, the choir started to swell for the last few notes, and the violist again couldn't find the high note. She was wobbling, trying to find that note, and the choir was drowning her instrument out. I saw that the violist had reached the end of her bow and still wasn't on the correct tone. It looked like a disaster was going to take place, so I prayed and was impressed to push the fader for the SM81 mic on the viola to the max. So I did! The mic fed back at exactly the correct frequency the violist had been wishing to play. I held the feedback note until the choir came down from the crescendo, then I backed off the fader. You should have seen the incredulous look on her face. She looked at her viola and then at her bow, trying to understand what had happened. It was one of those fun Christmas miracles.
