Joni Mitchell, who will be appearing for two days in August at the Pine Knob Music Festival, showed up for the Playboy Jazz Festival in the Hollywood Bowl recently to perform songs from her latest album, MINGUS — music by the late Charlie Mingus, lyrics by Mitchell.

It's an historical album, in a sense, since it was recorded before the jazz great died and shows a drastic change in style for Mitchell. Her poetic sense has adjusted to the erratic jazz melodies Mingus produced and her voice is smoother — lacking the yodel she used in most of her earlier recordings.

MINGUS, however, is unfortunately not a straight musical offering. There are a number of chatty studio cuts where the musicians are laughing and talking about nothing particularly interesting to the audience. I found this distracting. For me, MINGUS' music takes a lot of concentration, so to intersperse it with the insider's drivel was disturbing.

Otherwise, the album is exciting — especially to a long-time Mitchell fan who can see that she was not content to sit on a style that worked eight years ago, but wanted to make it grow.