AI, which is not guaranteed 100% accurate, offers this...
"NCH Crescendo does not have a dedicated feature to automatically play all instruments in their proper transposed keys so that all instruments sound in the same (concert) key during playback. Playback will use the written notation for each staff and play it back according to what you have entered for that instrument’s part. This means that for transposing instruments (like clarinets or trumpets), Crescendo plays the notes as written, not as they would sound in concert pitch, unless you have written their part already in transposed notation.
Transposing for Playback
Crescendo's playback feature will use the instrument MIDI you assign to each staff, but the playback key will correspond to the notes exactly as written in the notation, not automatically as transposed to concert pitch.
To hear all instruments in concert pitch (the same key), you must manually transpose the parts before playback. You can do this by using the "Transpose" feature found in the Score menu, which allows you to move all notes up or down by a specified number of semitones.
If you write the transposing part in its transposed key (as for Bb clarinet, written a whole step higher than concert), playback will match the part as written.
If you want all instruments to play back in the same key, temporarily transpose all transposing instrument staves to concert pitch using the Transpose function before playback, then undo for part printing if needed."