Miles made two visits to London’s Rainbow Theater in the latter half of 1973, both of which were documented by the band themselves using an on-stage tape recorder. Likely intended for more of a post-show critique session than any sort of official release, the tapes offer a distinctly different listening experience than our typical audience recording – the sound has an almost 3-dimensional quality, allowing you to place each instrument in the stereo field for pure sonic immersion. Listen for Miles pounding out tempos with his high-heeled boot and the moans of ecstasy from the musicians as the groove gets particularly nasty.

Compared to the heady, searching quality of the previous month’s Japanese shows and the meandering psychedelia of the officially released Montreux gig two nights earlier, the performance here in London is focused and downright muscular. Much of that is due to Al Foster’s powerful kick, which features prominently in the mix and has a grounding effect on the whole affair. Without a doubt the beating heart of the septet.

Set opener “Turnaroundphrase” begins to solidify into a familiar form, now featuring its trademark hard restart followed by Miles squeezing some incredibly high, almost feedback-like notes out of the horn. The momentum into “Tune in 5” makes for a seamless transition into the knotty 5/4 groove, with an expertly timed cooldown to counterbalance the intensity – it’s amazing to hear the band simmer with such precision here. Michael Henderson’s bass riff pulls us from the murk and into “Untitled Original 730424c” where Pete Cosey and Miles trade jabs with a tone so remarkably similar it’s often hard to tell who’s who. Miles drops a few stop/starts to heighten the drama, but the groove begins to lose steam just as the band gives way to an extended percussion outro from Mtume to close the set.

“Right Off” kickstarts the second half remarkably focused, though Cosey enters guns blazing with an incredible fuzz tone less than a minute in but quickly abandons it for reasons unknown. Miles uses a dramatic pause to cue in the next section (a move so well done you have to imagine the band rehearsed it), then solos with unexpectedly Jack Johnson levels of power and intensity. Listen as he gives some raspy cues around 10 minutes in. Both Foster and the tape wear thin toward the end of the tune before Mtume’s drum machine tumbles around the sound field to indicate our crossover into “Ife”. Clearly operating on familiar turf, the band sculpts the formless intro into shape beautifully here as Miles switches over to organ as it builds then lays into a giant atonal cluster at its peak. The tension release as he lifts his palms from the keys can be felt in your bones. “Calypso Frelimo” closes the set, peak on peak, outpacing its studio counterpart with Miles weaving into the mix like a bonafide keyboardist and Liebman’s tenor practically shredding the speakers. We’ve reached cruising altitude.

Get the tape (both sets)
First Set
1. Turnaroundphrase (11:55)
2. Tune in 5 (10:24)
3. Untitled Original 730424c (21:30)

Second Set
4. Right Off (13:38)
5. Ife (20:49)
6. Calypso Frelimo (12:20)

Lineup
Miles Davis (trumpet, organ)
Dave Liebman (soprano, tenor, flute)
Pete Cosey (guitar, percussion)
Reggie Lucas (guitar)
Michael Henderson (electric bass)
Al Foster (drums)
Mtume (conga, percussion)