Now that I've shipped off the Symphony in A minor to the Boston metropolitan area, I can fully concentrate on the Horn Concerto in B-flat major which I have been commissioned to write by a Canadian fan of Bruckner's music.
So far I've jotted down some melodies, listening to Horn Concerti as I worked on page turns and rehearsal letters for the Symphony, etc. I've also gone to the library and copied out some melodies from Masses by Michael Haydn and Antonio Salieri. And I've read the chapter specifically for composers in Gunther Schuller's book Horn Technique, plus reviewed the chapter on the horn in Kennan's classic orchestration textbook.
I think it was Robert (from a Yahoo! Group for Bruckner fans) who said that Bruckner's conception of the first movement of a concerto would have been filtered through his understanding of sonata form, and it's possible that he would have looked at Mozart's concerti as a guide. So I'm thinking a sonata form with three subject groups fitted together somehow with the ritornello/solo structure we'd expect from Mozart or the older contemporaries of his he used as models.
The piece should use four orchestral horns (even Bruckner's Study Symphony doesn't, if I recall correctly), but in the slow movement I'll have them switch to Wagner tubas. I'm not sure if in Bruckner's Seventh Symphony he expects the Wagner tubas to be played by the same horn players, but in my Concerto that will be the case, so Wagner tubas throughout the slow movement.
Brahms cast his Piano Concerto No. 2 in B-flat major into four movements, and I think Bruckner would also have done that, making the third movement a vigorous scherzo. For this purpose I plan to orchestrate a Minuet in D major for string quartet I wrote a few years ago.
The Finale should be a rondo. I think at least for his first concerto Bruckner would have so written it. The rondos Bruckner wrote as student exercises for Otto Kitzler pretty much go by the book, without the interesting deviations we sometimes find in Michael Haydn's secular oeuvre.
As for cadenzas, I will write them out but with instructions encouraging the soloist to make up his/her own.
It was yesterday that I pretty much laid out my plan to Ray, who commissioned the Concerto. He replied "Since my favourite Bruckner symphony is the Fifth, I am very pleased with your choice of key signature. As for the use of horns and Wagner tubas, that seems very novel and interesting! I also like your scherzo concept. This sounds exciting."
