Prom 40: Silk Road Ensemble / Ma, Royal Albert Hall, London

Some concerts, you'd think, can't fail.

Some concerts, you'd think, can't fail. This one included a superb female Mongolian singer sporting pink headgear with dark peacock feathers reaching to about 10 feet high, with a most extraordinary voice, plus a band including instruments such as the bamboo and bronze sheng (looks rather like a bagpipe, sounds more like an accordion) and the beautiful, lute-like pipa, to say nothing of virtuoso players on violin, cello, tabla and other instruments besides. But, although the capacity audience's applause for this Prom was enthusiastic, I wondered how many of them, like me, left a little disappointed.

The band was the cellist Yo-Yo Ma's Silk Road Ensemble, and the concert explored "the relationship between tradition and innovation in music from the East and West", inspired by the Silk Road connecting the Mediterranean to China. Three specially commissioned works, plus one that seemed to be basically structured improvisation, were supplemented by arrangements of Armenian and Gypsy music. Encores widened the net further, even encompassing variations on an English tune from Elizabethan times.

There were variety and virtuosity aplenty. The Mongolian Byambasuren Sharav's Legend of Herlen, featuring that singer, Khongorzul Ganbaatar, opened proceedings in style; you really believed that her spicy tone and amazingly long-breathed melody, spiked without warning by high ululations, could have been heard across the Gobi Desert, from where this vocal style originated.

By comparison, even Ma's fruity (and perhaps anachronistically Western-sounding) vibrato on a two-stringed "horse-head" fiddle, and the intermittent blasts from three British trombonists augmenting the ensemble, seemed tame. But we had to wait until the third encore to hear her again.

Zhao Jiping (who wrote the score to the film Farewell My Concubine) provided the piece I most enjoyed. Moon Over Guan Mountain offered rather fragmented yet occasionally melodic music for an ensemble including the sheng, a marvellous and versatile instrument, at least as played by Wu Tong.

The Indian tabla player Sandeep Das's Tarang gave four drummers, himself included, the chance to add some genuine interplay in improvisation, accompanied by a string group that then became a mainstay of this afternoon Prom.

The Armenian and Romany music was very affecting, with the Chinese pipa making natural-sounding contributions. Wu Man, the pipa player, is a fine performer. The Iranian Kayhan Kalhor was persuasive in a solo on the Persian spiked fiddle, but his ensemble composition, Blue as the Turquoise Night of Neyshabur, proved too long and lacking in thrust.

Booking: 020-7589 8212; www.bbc.co.uk/proms. Prom 40 available online to Sunday