A consistently exciting conductorless ensemble made up of members from all sort of big-name orchestras and chamber groups, ECCO returns for a pair of enticing outings: one inexpensive and the other free. This afternoon's event, part of the generous Schneider Concerts series, includes pieces by Mozart, Satie, Gesualdo, Ravel, David Ludwig and Judd Greenstein. Many of the same works recur on Mon 17, save that Jonny Greenwood and Radiohead replace Mozart and Ludwig.
