Bitches Brew Live captures two performances — one nine months before the release of Bitches Brew, the other four months after the album came out. It’s a document meant to show the evolution of Davis’s electric sound, and it does that well. The set from July 1969, played at the Newport Jazz Festival (and available for the first time ever here), shows the lean power under the album’s hefty atmosphere. The disc opens with an incendiary take on “Miles Runs the Voodoo Down”, and never looks back from there. The quartet — Davis, Chick Corea, Jack DeJohnette, and Wayne Shorter — knock these songs out with a frayed energy that almost feels like precision, even if each vamp is as unpredictable as the last. The 1970 set, from the Isle of Wight, adds Gary Bartz on sax and Airto Moriera on percussion, and you can feel the band stretch out with the new players. The power is still there, but the sound has more of that atmosphere, more rabbit holes to fall down into. There are hints of the more untethered sounds to come from Davis later in the 70’s, but this also sounds like Bitches Brew coming to live fruition. The band grew into the album’s space as a live outfit, and the results are pretty amazing — once they get to “Spanish Key”, even if you’re exhausted by all this intricate sound, it’s a funky shot in the arm. That said, this disc is still little more than a companion piece to the album itself, a curious look at how Davis translated those patchwork studio recordings to cohesive wholes on stage. And there are other documents — particularly Live at the Fillmore East — that’ll give you a similar, and perhaps better, experience. Still, just because this isn’t essential, doesn’t mean it isn’t a hell of a thing to listen to.