Chicago pianist Sun Ra emerged as a leader on the jazz scene early in 1956, when he assembled a group of neo-boppers that contributed to the original and exciting jazz sound offered by his new Sun Ra Arkestra, a medium-sized group that swung like a giant locomotive, an effect primarily due to an interesting use of two basses playing simultaneously.They featured the power of big band ensemble along with the excitement of combo blowing by fine soloists, among them the driving tenor John Gilmore, …