QUOTE(Aero @ Sep 16 2009, 11:22 PM)

As a general rule, F horn for sound, Bb horn for accuracy. I generally start on the F horn to see how natural they are. If they are doing fine I stick to that for a bit as it helps develop the sound and hones their accuracy even more. If they struggle, it's onto the Bb horn fingering.
Excellent plan!
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You need to know both anyway, it's just getting used to it. low G and middle G always on the F horn though.
Do you explain why, when to use 1 on the Bb for middle G, and what characteristics the other fingerings have?
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Of course this always depends on the pupil having a double horn.
I am surprised that the five-valve single Bb has never become popular. With the fourth valve set for hand stopping and the fifth giving an accurate F length, it has many alternative fingerings for better tuning and an adequate range downward for nearly all 2nd and 4th parts (only bottom G and F# needing some right hand tuning). It is lighter than a full double and cheaper for the same build standard. Alfred Brain, Dennis Brain's uncle, played one of these as the leading horn player in Hollywood in the thirties and forties. I suspect that the main defect of most of these instruments is that they are designed to be specialist 1st and 3rd instruments, with the mouthpipe and bell shapes chosen to make the overtone series best in tune around Ab or G horn length, rather than F or E, which would be normal for a double horn in F and Bb. PM me if you would like an expansion of the acoustics that explain this.
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I agree that a non horn specialist can do a lot of damage, but many know their stuff.
Agreed. You don't have to be a specialist, but you do need to know about each instrument.
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It's fortunate that it's not often on the horn that you need 4 octaves in one piece,
I couldn't think of one. I was thinking of Shostakovich 5 and the Schumann Concertstück.