I’m going with a “10” as well. Bitches Brew and Live-Evil have more aggressive surround mixes, but I find the music here much more accessible.
The layout of the 5.1 mix is relatively simple, but very effective--it sounds absolutely huge, despite coming from what I'd guess is an 8-track master. The center channel acts as the focal point of the performance, containing Miles’ trumpet and the bulk of the drum kit. However, there’s also a fair amount of drum sound in the rear channels--so listening from the sweet spot gives the impression of that hypnotic drum pattern projecting directly inside your head. It’s definitely one of the coolest uses of phantom imaging I’ve heard in a 5.1 mix.
The front soundstage has John McLaughlin’s guitar on the left and Wayne Shorter’s sax on the right, but neither is panned entirely to one side--they’re sort of hovering in those spaces between the center and front speakers. The rears are reserved primarily for the keyboards--I think there's one in rear left, one in phantom rear center, and one in rear right--and some nice ambience from Miles’ trumpet. It's like being in a completely enveloping, immersive bubble.
Finally, the sound quality and mastering are excellent--you can really crank this up, and the noise floor is quite a bit lower than the original stereo mix (though not entirely erased). If you like the music, don't hesitate to track this down.
