John Lubbock, artistic director of Orchestra of St John’s, explains the best way to bring spontaneity to a piece

For me the most important element of music making is spontaneity. Each performance should be unique and completely appropriate to the moment.

How do you ensure that each performance is unique? Well, the one thing you don’t do is rehearse the performance. Let me tell you what I do in rehearsals by introducing the analogy of the world of Formula One motor racing.

Without wanting to insult the musicians, an orchestra is a very complex unit with many moving parts which all contribute to the end ambition just like a Formula One racing car. The conductor is the driver — the track is the piece of music and the practice lap is the rehearsal.

What is happening during a practice lap? The driver/conductor is taking his car/orchestra round the track/piece to see a) the layout of the track/piece and b) how his car/orchestra responds and to discover how each cog in his enormously sophisticated machine functions in order for him to go round as fast as he can. Each cog/player is finding out how he/she can negotiate the various corners or inclines or characteristics of the track/piece. This produces a huge credit in each musician’s bank of knowledge about the piece of music, allowing the musicians to deal with whatever happens in the performance.

I will know the piece of music sufficiently well that I can completely blank my mind before I give the first downbeat, so that I am not making any predetermined decisions about the actual speed of the music. This will ensure that the speed is appropriate for that precise moment. Interestingly enough, for our live recording we record the rehearsal to patch any blemishes in the performance. Very often we cannot use the rehearsal as it was a slightly different speed.

This approach to performing can be rather dangerous for the musicians, as no one truly knows how the performance is going to go. When it works however, it is a wonderful experience, and I am lucky enough to have in my musicians a group of people who are willing to risk this roller coaster ride. Many orchestras, as I have found out, want the conductor to tell them how the performance will go as life is easier and less stressful that way.

What has always been clear to me is that spontaneity and compulsion are mutually exclusive. A performance really works when everyone on stage is in exactly the same place at the same moment entirely voluntarily. For this I am totally reliant on my players to show an enormous degree of generosity and selflessness to put all their musical talent and experience at the mercy of the moment. This will nearly always produce a result that is infinitely greater than the sum of the parts.

Forthcoming concerts include: OSJ Proms at the Ashmolean Museum, Oxford, on Wednesday, February 19 St John’s Smith Square, London, on Friday, March 14. To book tickets visit www.osj.org.uk