Last week, we listened to Eddie Cochran perform his "Summertime Blues" in 1959. In 1969, The Who, above, played the song at the Woodstock Festival (at another concert, singer Roger Daltrey said that it was "the only song we do by another composer"). In listening to both, we hear the changes that rock underwent in a decade. In the Cochran version, the focus was on the singer and the band's purpose was to serve as backup. With The Who, the individual musicians also stood out. The guitar emerged as a solo instrument, and technology tremendously boosted the music's amplification. There's something to be said about the powerful impact of such changes–and something also to be said about Cochran's more stripped-down, basic sound.