It's music to my ears: and eyes, and brain

At last! Schoenberg's 12-tone system explained. Sue Gaisford heaps gratitude on Leonard Slatkin

Everyone knows about music. It's what you hear in shopping centres and supermarkets. It tinkles maddeningly out of the telephone, and thunders, distorted, over station platforms. Dentists use it to calm the nerves, and surgeons play it to soothe the unconscious patient and to steady the hand with the scalpel. Advertisers link airlines or cigars to a famous tune, hoping we'll buy. Music spurs the vigorous to dance and it lulls infants to sleep. It is everywhere.

Occasionally, we choose to listen more attentively. But do we know what we are listening to?

We can recognise tunes, of course, and most of us know what we enjoy and what we find excruciating. Sometimes we can switch off, or walk out. People whose careers and lives are dominated by music have a entirely different attitude, because music demands all their attention, but your average audience is less focused. "The problem with audiences," as Leonard Bernstein once said, "is that they hear too much music but they don't really listen to it."

The American musician Leonard Slatkin is well aware of this problem and has decided to do something about it. As a conductor, he is famous for talking to audiences all over the world about what they are about to hear, introducing and generally demystifying it. Now he wants to help the rest of us to "listen to music, really listen to it, to understand some of its principles and at the same time to come away with a real enjoyment and a sense of well-being".

Such a combination of enthusiasm, ability and knowledge is, thank heavens, still irresistible to BBC Radio 3. For 10 days over Christmas, they will broadcast his series on discovering music. It is a degree course, inside a fortnight. I have heard the first two and enrolled.

Slatkin was inspired by Aaron Copland, whose 1939 book, What to Listen for in Music, started by dividing musical experience into four groups: rhythm, melody, harmony and tone-colour. Slatkin does the same. He starts by teaching us how to count, while the band plays on: "One two, three, One two three - on your own!" His collaborators are the BBC Philharmonic as you've never heard them, performing with agile flexibility and making deliberate mistakes. In the second programme, for example, he gets them to play a famous tune from Tchaikovsky's Fifth Symphony. Then he changes a note, so that we can hear the difference, then another note. It sounds quite nice, actually - and he agrees. "I don't think there was anything wrong with the changes we made," he remarks. "It's just Tchaikovsky knew better".

From here, he leads us into thinking about what makes a melody, about the steps and leaps between notes, and thence to the four main systems of scale-building: oriental, Greek, ecclesiastical, and modern. Before we have a chance to become dazed, he plays seven wildly differing snatches of melody - an Indian raga, a medieval organum, gamelan music from Bali, Jewish and Hungarian tunes, and finally, Messiaen and Palestrina. Immediately, you see what he means, how they are all related by interval. Next, he chooses four notes and demonstrates how this sequence has been used by another handful of great composers - and yes, the connection between Handel and Richard Strauss emerges.

But the really clever bit is just coming. There's a problem for some of us in appreciating the work of Webern and Schoenberg - but don't panic. Slatkin describes and illustrates Debussy's discovery of the 12-note whole- tone scale and explains that Schoenberg and Webern, who thought that Western music had got as far as it could go, fell on this new scale with glee. But, "they decided that they would take these 12 notes and play them, without sounding any note twice before the other 11 had been heard. It made it very difficult for performers, and extremely difficult, to this day, for many listeners".

No wonder it's hard: it's not music, it's algebra. Slatkin acknowledges that many would not describe the Webern he played as melody, though technically you could. He leads us back towards Brahms, plays seven tiny snippets of the finale of his First Symphony, and then lets rip with the whole movement. By now, an hour after the subject of melody had been introduced (by Frank Sinatra and Ella Fitzgerald), at least one listener is brimming with new-found confidence in her knowledge of scales, intervals, and great tunes.

By the end of the 10th lesson - sorry, programme - I hope to be able to sound off about the symphonies of John Corigliani and Tan Dun, and to pinpoint precisely the notes stolen from Kurt Weill by William Bolcom when he wrote his Sixth Symphony. Honestly.

'Discovering Music with Leonard Slatkin': Radio 3, daily from tomorrow.