Initially, when Columbia owned the project, the studio executives wanted to hire musicians to re-record all of Parker's music, largely because most of the original recordings were in mono, and considered of insufficient sound quality to accompany a feature film. Eastwood had some recordings of Parker made by Parker's wife, Chan, from which he had a sound engineer electronically isolate Parker's solos. Contemporary musicians such as Ray Brown, Walter Davis, Jr., Ron Carter, Barry Harris, and Red Rodney were then hired to record backing tracks on modern sound equipment. Dizzy Gillespie was on tour at the time of recording, so trumpet player Jon Faddis was hired to record his parts. Most of the tracks are up-tempo, including a delighted nightclub audience as a part of the scenery. And, isn't that the way it was with Parker? Everyone sat up and took notice. No one could keep still when the maestro performed. He was a pepper-upper who charged everyone around him with considerable energy.