What is transposition in music ?
There’s 2 kinds of transposition but they are related. In a band or orchestra some instruments are transposing instruments. For instance, a Trumpet is keyed in Bb relative to a nontransposing instrument like a piano or violin which would tune in A. Therefore, a piece of music written with no sharps or flats in the key signature woukd have to be written in Bb for the Turmpet. Other instruments use other keys. In a score (showing all the instruments like what a conductor would use, you would see all sorts of key signatures depending on the instrument. The other kind of transposition is changing from one key to another. Going from one key to another is known as modulation more commonly than transposition, but, if you wanted to play a piece written in say, C Major or minor, and wanted to perform it in say, A Major or minor. (frequently done for singers), you would re-score (re-write) the whole piece in the new key, paying attention to the sharps or flats and most especially, the incidental
