Some are born great, and some are picked by BBC2. Great Composers launched its preferred seven (Bach, Mozart, Beethoven, Wagner, Tchaikovsky, Mahler and Puccini) on Sunday with a synthesised collage of juicy bits by them all. In case you hadn't got the message about supermen, it cut to a space shuttle lifting off. And if you stayed with it, the programme then sprang its surprise: a documentary about Johann Sebastian Bach so respectful and decent that it could have stopped Lord Reith turning in his grave.

Here was Kenneth Branagh telling the life story with modesty and directness. There between the chapters was a parade of reassuring Germanic types like descendants of the bourgeoisie Bach wrote for, and the English version in grey pullovers. They talked about the music and they played and sang soundbites, in varying states of quiet transcendence. This was a show of unity in worship to make the churches pine with envy.

The message of the wall-to-wall WASPs was strangely excluding. What were they all so certain about? Why wouldn't they say? You had to latch on to any sign of excitement. Ton Koopman went slightly crazy and transported, as is his way. Joanna MacGregor atoned for incipient waffle ("a very simple early harmonic style") by waxing urgent about the Preludes and Fugues. Jacques Loussier invented his own versions, and that was without playing jazz. Unexpectedly, John Eliot Gardiner let it all hang out over the B minor Mass and paid off a worrying deficit in the joyous side of Bach's music that had built up since the programme began.

Otherwise, viewers who didn't "get" the religion must have found it a puzzle. The trouble, on this showing, was that the question-begging premise of the series stood in the way. Hanging the story of classical music on seven composers would have looked dodgy even in the age of Civilisation, which at least respected the tides in the affairs of man. Now it looks like a late product of back-to-basics philosophy, mixed with a dose of Great Man theory.

We grow up in a complex musical environment that makes us hear much without taking it in. Ears have walls. Granting a few composers divine status doesn't suddenly bring them down. Focusing on the music has a better chance. At the end, a complete performance of Bach's Dona nobis pacem spoke, all right. Even continuity fell silent. But who else was still watching?

Half a night later on Channel 4, Yo Yo Ma took his cello into the Kalahari and played Bach to a crowd of villagers. They fell silent too. Ma was following an old fascination with some African music and wanted to search for common ground. It looked like a stunt, as he paraded this huge, loud, shiny instrument before his rural audience. Must be a missionary. But Ma seemed so good at meeting them, and so frankly aware of the cultural pitfalls, that it made a riveting experience. There were long shots of musicians just figuring each other out, slowly and happily. Anybody watching would have "got" both the African music and Bach, no trouble.

Shame about the final shot of him playing on his own in front of a fire, as though Africa had gone away, but it didn't erase what had taken place. To quote the late Sir Laurens van der Post in an on-camera conversation with Ma, the adventure was about crossing bridges that others treat as barriers. This time, no barriers.

`Great Composers' continues with Mozart this Sunday at 7.45pm on BBC2. The complete set of seven programmes is already available on video from Warner Vision.