I just returned from a performance of Mahler's 9th and at various parts in the piece the horn players held their instruments quite high...was just curious to know why??

It's all to do with the sound projection

Yes. Occasionally a composer will want a much clearer horm sound and instructs the players to hold the bell aloft. This allows its beautifil mellow sound to cut accross the orchestra more clearly. Another quite common effect is hand stopping. Here the player is asked to close off the bell with the right hand and creates a haunting, buzzy tone. This will require the player to transpose the part also as the pitch is altered by the hand stop.

It's called 'Schalltrichter auf', 'bells up', he uses it for clarinets and oboes too. Allegedly to get more sound over as Ben says, although I'm sceptical as to how much difference it really makes.

It looks great though!

Chris

This reminds me of a corgi once owned by my inlaws. A siren used to be used in the town to call the (volunteer) firemen to service. Rusty was generally a quiet dog, but when this siren went off he would jump on to chair (to increase his height), he would tilt his head back with his nose as high as possible in the air and emit an eerie howl ! It must have been his (presumably Welsh) version of Schalltrichter Auf !

Bells up gives more projection yes but also to give a more raspy edgy and raucous sound like the old hunting horns, which is eliminated somewhat by the hand in the bell.

Because horns are pitched to take into account of the hand in bell effect, bells up usually sharpens the tone noticeably...but it's Mahler, who cares?

Thank you! I did wonder if it was something to do with the sound.

True - although speaking as an oboist it's darned hard to get your bell up, keep your reed vaguely in the right position, and still be able to see the music.

You also feel like a right idiot if you're the only one in your section of 6 doing it (as has happened to me - amateur orchestra, conductor who obviously hadn't noticed or didn't care)

Can a bassoonist play in any other way?

nope - but mahler asks us to play low As so we have to stick rolled up paper in our bells, which looks just as silly

It's pretty hard as a clarinetist as well and trying to keep the intonation under control well

I think at least on the clarinets it does change the sound quite a bit a much edgyier racous sound.