Question: who were the principal musicians of the jazz avant-garde

title: Cool jazz
text: In 1948 , Miles Davis formed a nonet including Mulligan , Konitz , and Evans from Thornhill 's orchestra . Capitol Records recorded the group ( at arranger Pete Rugolo 's suggestion ) in 1949 and 1950 . These recordings , originally issued as 78 rpm records , were later compiled as Birth of the Cool ( 1957 ) . Gerry Mulligan explained that the idea behind Davis 's Nonet was not to get away from bebop , but `` just to try to get a good little rehearsal band together . Something to write for ... As far as the ' Cool Jazz ' part of it , all of that comes after the fact of what it was designed to be . '' As for Davis , his concern at the time was simply to play with a lighter sound , which he believed to be more expressive . Also his choice of notes suggested great deliberation rather than wild exuberance