Thanks Paul, just what I was looking for. I have been nibbling round the edges of this sort of thing for a while with the hope of writing some software to do it, mainly for dance tunes rather than song. I might start another thread on the subject when I've done a bit more thinking. I don't think your points (i) and (ii) are quite as staightforward as you thing and the process might not be quite so easy to do as all that. Could you give me a link to your website please?

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