Jam band

Jam bands are musical groups whose albums and live performances relate to a fan culture that originated with the 1960s group Grateful Dead and continued in the 1990s with Phish and similar bands. The performances of these bands often feature extended musical improvisation ("jams") over rhythmic groove and chord patterns and long sets of music that cross genre boundaries. While the seminal group Grateful Dead were originally categorized as psychedelic rock, by the 1990s, the term "jam band" was used for gr