A trained soprano approached me recently about adapting a famous Buddhist song, arranged for four-part voice, for a 45-person amateur choir, pianist, cello, and saxophone.
As typical of Chinese songs, it is written in jian pu, which means simplified notation. She explained that the original key of F major is too high for choir members. As there are few male singers and the melody carried by the men, some of the women have to double up.
The beauty of using simplified notation is that there is no need to transpose. The numbers correspond to the notes in that particular scale. Thus 1 represents do, 2 is re, 3 is mi, etc. In the key of F, 1 is the tonic of F, 2 is G, 3 is A, etc. In the key of D, 1 is D, 2 is E, 3 is F#, etc.
As the choir members practice to a recording, it would be necessary to either transpose the recording to the new key, which can be done by such software as Audacity or record the accompanying instruments playing in the new key.
As for the instrumentalists who don’t read jian pu, some may be able to transpose note by note into the new key. It may be easier, however, to specify the chord progression first, e.g. I, IV, V, etc, and then label the new chords in the new key. I am curious how the pianist accompanies the choir, for the sheet music indicates only the melody lines and verse. Similarly how does the cellist figure out the bass line – by ear? It seems rather odd to have a saxophone in the mix.
Perhaps I should do some homework before attending the rehearsal next Monday in Zuilen, a borough of Utrecht in the Netherlands. Without a piano and a computer with notation software, I am limited in what I can do.