I'm about to ask a question that has made many a music teacher cry when they attempt to answer. Prepare yourselves.
I really don't understand why some instruments have different tunings, e.g. "Horn in F" and "Clarinet in A" or "Bb". Is it something to do with playabillity? I'm a violinist, so I'm used to concert tuning, and although Sibelius has a useful tool where you write all parts in concert tuning and it will transpose automatically whenever you want, I would feel more proffessional if I new the theory behind this.
And on that note - how does one transpose to and from these different tunings. Is it just a matter of counting up or down a few semitones (despite the fact that the note stays at the same pitch, as I understand)?
Any guidance from yourselves would be very helpful, but a link to a page explaining this would be equally useful. I hope to eventually understand the reasons behind the tunings, and be able to transpose myself manually, should the need arise.
Have a nice day,