Despite a relative heatwave in San Francisco, and Fleet Week, which means the sound of the Blue Angels roaring over, the devoted members of LAB XVI are working hard with Ben Johns, their co-director,  having long sessions Friday, Saturday, and Sunday.   Yesterday they were putting in place the rhythms and Russian in Sergey Taneyev's "Behold Darkness Has Fallen" - a tricky task we know well because it's on our "My Secret Heart" program.  We're in Seattle for the weekend, doing two performances of "Washing of the Water" at the Illsley Ball Nordstrom Recital Hall - our first time there.  We'll be back Monday to prepare for our Youth Choral Festival on October 14.