I feel I am very proficient with music theory (though I was not an orchestral major). However, I am trying to play a written part of a score for a trumpet and am having some transposition problems. Here is the scenario: The score is in Dminor. The trumpet part is listed as "3 Trombe(B)" which means 3 Bb trumpets. However, the part is written in Am - just like the Horn section(which are F instruments). This is either a typo in the key signature, or a typo in the type of trumpet. Anyway, the first note is B below middle C. I thought I could play the part into Sonar as written but use the midi transpose function. I transposed it "-7" to take it down a 5th for the key. This could be where I am mixed up...but anyway.... When I play the part into Sonar, the "B" I play - I suppose this would really be an "E" - is below the playable range of my sample library. So here are my questions:
1) Do I have this set up incorrectly?
2) Could it be the sample library does not cover the entire playable range of the trumpet?
3) What the heck is up with the key signature being in Am?