January is Kubrick month in Sydney. On the 24th and 25th the Sydney Symphony will perform the music of 2001 live at the Opera House, with a screening of the film. On January 26, in a free concert in the Domain, the orchestra will perform The Sound of Kubrick, a selection of pieces used in his films, from Beethoven, Bach, Purcell, Rossini, Khachaturian, Bartok, Shostakovich and Tchaikovsky.

This might have amused Kubrick, given how he used some of these pieces. In A Clockwork Orange, Rossini's William Tell Overture accompanies a scene in which Alex (Malcolm McDowell) has sex with two young women picked up in a record store. Context is everything.

Without his images, these pieces lose the power that came from his extraordinary talent for juxtaposition. At the start of 2001, Johann Strauss's Blue Danube Waltz comes in over the first view of the spaceships floating benignly in the deep black pool of space. The scene seems to express man's supreme technological and artistic sophistication - a waltz of the machines - except that it comes straight after the bone-cracking monkeys. There's a whiff of irony.

Kubrick gave us what Arthur

C. Clarke, his script collaborator, called the biggest flash forward in the history of cinema, across 3 million years, with a match cut from the bone thrown into the sky to a spaceship shaped like a bone. These spaceships were to be orbiting nuclear weapons. Kubrick pulled back from that, because he didn't want to evoke Dr Strangelove (1963).

Kubrick starts us thinking instead about whether we have evolved, become civilised. The waltz suggests manners, rather than civilisation. Before that Kubrick gives us three minutes of blackness in the overture, accompanied by the searing, dystopian hum of Gyorgy Ligeti's Atmospheres. This serves as a warning: abandon hope, all ye who enter.

All of these pieces were taken from existing recordings. Kubrick didn't bother to re-record them. With the Ligeti, he didn't even get permission, so the Hungarian composer sued him. After a settlement, Kubrick also used Ligeti in later films.

Beginning with 2001 in 1968, on through A Clockwork Orange (1971), Barry Lyndon (1975) and The Shining (1980), Kubrick's use of music had a big impact on the way later generations thought about film music, and not always in a benevolent way.

''I don't think he is a champion of classical music at all,'' says Paul Charlier, an Australian composer and sound designer with a long-standing interest in the history of sound.

''I think that what was innovative was not so much his use of classical music, but that he used extant recordings of classical and modern orchestral music. The effect was profound in that over time the influence was to free directors from the mould of how music, especially orchestral music, was composed, produced and incorporated within film.''

2001 was not so much a watershed as a reflection of his times. The Beatles were splicing takes together on Strawberry Fields Forever while Kubrick was cutting 2001.

Kubrick treated recordings as ''found objects''. He did not stand in awe of the traditional Hollywood score or those who wrote them, or even classical and contemporary composers.

In effect, he helped to reduce the hegemony of the big orchestral scores that had so dominated the 1930s and 1940s in films such as Gone with the Wind and Rebecca. For a while after 2001, those big scores were less dominant until John Williams came along with Star Wars.

Charlier argues that Kubrick opened the door for those modern directors whose style relies on existing music rather than original composition.

Martin Scorsese used Bernard Herrmann on Taxi Driver and Quentin Tarantino used him in Kill Bill, but both avoid original film scores. Tarantino says he is reluctant to give anyone else that much power over his movies - a telling statement.

Kubrick intended 2001 to be a non-verbal film, appealing directly to the subconscious, and music was a key to that.

He commissioned Alex North to write a score, then famously did not use it. He never used movie composers again, and they weren't gracious about it.

Herrmann has said: ''It shows vulgarity, also, when a director uses music previously composed.

''I think that 2001: A Space Odyssey is the height of vulgarity in our time. To have outer space accompanied by The Blue Danube, and the piece not even recorded anew!''

Kubrick did not just abandon traditional scoring, he avoided what Charlier calls the ''parasitism'' that still afflicts film music. Music has often been used simply to supply something not there in the image - missing emotions - or to intensify the effect of something that is already there.

Charlier says Kubrick did not do that. He didn't need to: his images were already strong enough by themselves.

When Kubrick added music, it was to transform a scene. One + one could equal three.

The music was not subservient, except to Kubrick. He may not have had great respect for film composers, but he did for the power of music itself.

2001: A Space Odyssey is on January 24 and 25 at Sydney Opera House. Symphony in the Domain: The Sound Of Kubrick is on January 26.