The presence of a concert-score element indicates that a score is displayed in concert pitch. It is used for scores that contain parts for transposing instruments.
A document with a concert-score element may not contain any transpose elements that have non-zero values for either the diatonic or chromatic elements. Concert scores may include octave transpositions, so transpose elements with a double element or a non-zero octave-change element value are permitted.
The
<concert-score>element.The presence of a concert-score element indicates that a score is displayed in concert pitch. It is used for scores that contain parts for transposing instruments.
A document with a concert-score element may not contain any transpose elements that have non-zero values for either the diatonic or chromatic elements. Concert scores may include octave transpositions, so transpose elements with a double element or a non-zero octave-change element value are permitted.
See
https://www.w3.org/2021/06/musicxml40/musicxml-reference/elements/concert-score/