Herbie Hancock, Town Hall, Cheltenham

Herbie Hancock arrived at the Cheltenham Jazz Festival with a new quartet, a light-show, and a small but significant array of electronic enhancers that allowed him to create incredible soundscapes at will while still holding firm to the belief that this was a primarily acoustic band.

Herbie Hancock arrived at the Cheltenham Jazz Festival with a new quartet, a light-show, and a small but significant array of electronic enhancers that allowed him to create incredible soundscapes at will while still holding firm to the belief that this was a primarily acoustic band.

Hancock, dressed in immaculate cool fashion in jeans, sports jacket and casual shirt in three different shades of black, was seated at a concert grand piano for most of the evening.

But on top of that piano was a synthesiser keyboard, plus an Apple iMac and other sound generators. His drummer, the impossibly young-looking Ritchie Barsay, had an electronic drum pad in addition to his kit; his acoustic bassist, Dave Carpenter, from time to time strapped on a six-string Fender electric; while his guitarist, Lionel Loueke, played electric guitar with a vast array of foot pedals and switches. As Hancock put it, "This is an acoustic band that uses electrics."

What it also used was Hancock's vast imagination and experience. He has an uncanny ability to build and shape a performance from the smallest of elements: here, he sampled a sliver of the spoken introduction by Tony Dudley-Evans, the festival director, and did all manner of alarming things to it as the first number quietly began.

A second long excursion began with Hancock's beautiful theme "Sonrisa", which debuted on his early 1980s solo album The Piano, recorded in Japan: this was fashioned into something that became as vast as Gregorian chant, but as contemporary as the latest fusion of world and western musics, with electronics attached. It was also at times very moving.

Throughout all that, the young band largely responded with great sensitivity to the challenges Hancock handed them. It was at times equally challenging for the audience, for the music demanded total concentration, each piece being in the region of 15 to 20 minutes long, and the concert ran for well over two hours, with no interval.

It could have been less onerous if the inconsistent guitarist, Loueke, had not been given so much room (a Hancock trio would have been sensational in this format). Yet Hancock himself was in a great mood and scintillating form. He chatted good-humouredly to the audience, and with great charm: he also smiled spontaneously at his colleagues' playing, deriving pleasure from their fresh invention.

But Hancock himself delivered the most telling music of the night, his occasional solos being staggering spontaneous constructions. By the time the concert ended, the audience was almost too exhausted to demand an encore, but they gamely pulled the quartet back and Hancock rewarded them with a darkly beautiful acoustic piano introduction to "Maiden Voyage" that took the breath away. No matter that the band then smashed on for another 15 minutes: that intro will stay in the collective memory for years.