In a year all but bereft of upsides, streamed concerts have offered something close to a silver lining. They’ve flung open doors to otherwise inaccessible performances — whether fiscally or physically — and abetted novel performances that might not have happened otherwise, like a freewheeling Pauline Oliveros opera staged over Zoom last April, cellist Seth Parker Woods’s audiovisually mouthwatering performance of a work inspired by The Chicago Defender (and composed by the inimitable Nathalie Joachim), and Spektral Quartet’s lineup of side-splitting, chin-stroking conversation series.