London African Festival, South Bank Centre

The London African Festival was a nice idea, and the main events promised much: I was looking forward to hearing the Cameroonian diva Sally Nyolo, whose CD Beti is a most beguiling evocation of rural life. But from the moment she came on at the Queen Elizabeth Hall - supported by a dancer, two electric guitars, a drum-kit, and a busy drum machine - the reality was rather different.

As if to make up for the fact the auditorium was half empty, the amplification was turned up high: the result was a desperate village-hall effect. A small claque gave dutiful whoops at the end of each number, and Nyolo and her dancer spent a lot of time switching veils, but there was absolutely no spark between stage and stalls.

Would it have helped if her words had been audible, or if we'd had a commentary telling us the context of the songs? Possibly. When we did hear her voice above the mechanical din, her strong, boyish timbre was a reminder of what she was about. But most of the time her engaging personality remained woefully under-projected.

The next night we got Thomas Mapfumo - the Lion of Zimbabwe - at the Royal Festival Hall, where he was given a hero's welcome. "Thomas Mapfumo is in the house" shouted his herald, whereupon cheers and ululations rang out all round. The moment the first instrumental number began, half the audience rushed down to jive in the aisles. And when the Lion himself appeared, it was with the slow and measured gait of an emperor.

His musical style has always been spare, but here he was positively laconic, crouching and posturing while his official dancing girl whirled about, and seemingly addressing his few words to the audience-dancers just under his nose. Would this musical freedom-fighter give us the dope on present-day Zimbabwe? Nothing beyond a brief assertion that "all the songs are revolutionary", but at least he didn't drown them out with technology. His three-piece wind section blended nicely with the mbira thumb-pianos, which set up a merry carillon above the heavy bass below.

But the following night, magic descended from an unexpected quarter. Tipa is Tibet's indigenous operatic art-form, created in the 14th century and now pursued by Sugkyi Nyima, a troupe based at Dharamsala. On came four musicians - with plucked and bowed strings, plus a zither - followed by five apparitions from the most fantastically colourful dream.

We were treated to two moral tales about love and fidelity, and though the language was strange, the flowing grace of music and movement spoke volumes. The range of vocal timbre was astonishing, and though the musical rules were hard to fathom, one sensed that they had the rigour and cogency of our own.