Question for music composers/arrangers

[Star Treks]

Hey, thanks in advance if anyone can help me with this.

I'm writing a jazz piece which includes a part for B-Flat trumpet. Originally I wrote that part in C but now I have to transpose it properly.

The trumpeter told me to transpose not only the notes, but the chords (there is an improvised section where I list what chords to improvise in).

I just want to be 100% sure I get this right. If I wanted him to improvise in the key of Concert D Major, should I put "E Major" or "C Major" in the score - the whole step higher or lower?

 

[Maestro]

Everything should be transposed up a Major 2nd, or a whole-step.

If the piece calls for improv in the concert key of D Major, the Bb trumpet part should direct the trumpet player to improv in the written key of E Major. Or, you could just say fuck it, and note in the part that the chords aren't transposed and expect the player to do the transposition on his own, which is something that a well trained trumpet player should be capable of.

 

[Star Treks]

Everything should be transposed up a Major 2nd, or a whole-step.

If the piece calls for improv in the concert key of D Major, the Bb trumpet part should direct the trumpet player to improv in the written key of E Major. Or, you could just say fuck it, and note in the part that the chords aren't transposed and expect the player to do the transposition on his own, which is something that a well trained trumpet player should be capable of.

Thanks, I'm glad to hear this, because that's what I did, before I was suddenly seized with a fear that I'd transposed it wrong.

He's a decent trumpeter but he seems to be fairly weak at any type of transposing, so I want to make the score as easy for him as possible.

Appreciate the help!