The first concert I attended was the Spectrum Pop Festival in 1969. I saw the Friday night show. I went primarily to see the Mothers of Invention and Ten Years After but was most impressed by Sly and the Family Stone. I saw them again at the Spectrum in 1971 (when Sly was still showing up on time or close). They were so loud, they made the built-in hockey rink at the Spectrum vibrate! The Jeff Beck Group must have included Rod Stewart then but I don’t remember him. Savoy Brown didn’t show up. Sets were about a half hour with about another half hour in between performers.
For me, the highlights of the Woodstock film were Sly, Ten Years After, and Santana. I was glad I got to see two of them in person just a few weeks earlier.