All demos are from John Coltrane's 'Africa/Brass' era, his 1961 debut for the record label.

The excavated tracks may give insight into how Elvin Jones and John Coltrane evolved as they recorded more takes.

American jazz record label Impulse! Records was established in 1960 by producer Creed Taylor.

Initially a subsidiary of ABC-Paramount Records and based in New York City, the label is now part of the Verve Music Group.