The musing following my previous post has lead me to think about why the setting is weak, and I've come to realise that this is due a lack of any narrative drive. It is simply there as a backdrop to the action.
It's occurred to me that an underlying assumption in the majority of amateur performance - be it theatre, orchestra, choir or whatever - is that people will go out of their way to see it. In reality, audiences are generally strongly biased towards friends/relatives of the performers, who will have been 'encouraged' to attend. There are exceptions of course, but if an amateur group suddenly ceased to exist, hardly anyone not involved would notice or care. This is in stark contrast to professional groups. Furthermore, the audience's appreciation is often insensitive to the quality of the performance. The performers tend to behave as if the performance were as important as for a professional group - understandable, as it is their pastime - even if the standard falls far short of that (talking the talk?). Would the performers actually like it if they got what they wished for? Would an audience of 3000 and a frank review in The Times really please an amateur group?
Bearing this in mind, I wonder if the orchestra storyline could be made to stand up on its own by turning this on its head - perhaps setting it in a world in which amateur performances share the same properties as professional ones (large audiences, reviews in major newspapers etc.), perhaps setting it in reality but having the (poor) orchestra suddenly become famous.
It's not quite right yet, but I think it's a thread worthy of more thought.