Not since the days of Roland Kirk, Albert Ayler and the Charles Lloyd of the '60s have Cleveland audiences seen such an exuberant and musically exciting performance as that of the Thomas Chapin Trio at the Bop Stop October 17. You could hear echoes of Kirk, Ayler, Lloyd and Henry Threadgill in Chapin's stylistic approach to the alto sax, soprano and flute — if you were a member of the predominantly youthful audience (mostly in their early 20s) who roared with approval at the mixture of free jazz, bop and r&b, presented with