For the last 30 years, Bobby McFerrin could have contented himself with just being, as they say, "an act" – and an unrivalled one at that. Possessed of a four-octave voice, lightning improv reflexes, and the ability to mimic everything from an opera bass to a Charlie Parker bop solo via the sound of a car shifting gear, he remains the master of the solo-voice show.
But an act he refuses to be, and even at a Barbican concert (backed by Pete Churchill's fine 28-piece London Vocal Project) hooked to his most ambitious-ever album, McFerrin still spent much of the gig jamming with his fellow performers and the audience. Inevitably, his skills invite a: "How the hell does he do that?" But he also reminds listeners that all humanity carries the same instrument as him – and that music's roots are communal, which stardom has no business obscuring.
Typically he began seated, quietly singing a little uptilting falsetto melody while beating the groove on his chest. A deeper, soul-vocal line emerged (in McFerrin's private language, which sounds like English but isn't), then his trademark register-leaping skids, ending on a finger-snap. He then got the choir to sing a riff to the basses, playfully conducting its spontaneous overlaying all the way up to the sopranos, before unfurling his own improvised line over the top.
A yodelling traditional blues with mimicked slide-guitar fills followed, then a cheesy Fly Me to the Moon, and a Flight of the Bumble Bee delivered as if the insect were buzzing around his head. Later came a whispered Bach Prelude No 1 while patches of the audience sang the Charles Gounod Ave Maria counterpoint. In between the solo flights, four parts from the singer's new multi-genre VOCAbuLarieS album were conducted by their composer Roger Treece – complex, vividly coloured tapestries often phrased as emphatic African tribal chants.
The choir sounded at its most assured and impassioned on this rehearsed material, but though Treece's writing was deft, it veered toward a westernised Lion King gloss that faintly jarred with McFerrin's warmth and naturalness.
In the end, however, it was the duets with the audience on everything from James Brown's I Feel Good to McFerrin's own Don't Worry Be Happy, the astonishing beating-wings sound in the Beatles' Blackbird, a flawless account of Charlie Parker's Donna Lee, and the homely Q&A session with musical illustrations (instead of an encore) that reverberated afterwards.
