Every summer, the Boston Symphony Orchestra goes out to the Berkshires for a few weeks and plays a bunch of extraordinary music out among the trees and hills during a festival they call Tanglewood. Next summer’s season is the 75th anniversary, and the schedule that the BSO announced yesterday has a few callbacks to 1937 scattered throughout it, including the season-opening all-Beethoven concert July 6. The symphony is also running headlong into the modern age: the concert will be broadcast on BSO.org, and throughout the summer, 75 archived streams of Tanglewood performances will be offered for download. Tickets go on sale January 29. (FULL STORY: Andrea Shea, WBUR)