Transpose instruments by looking up the difference between a concert pitch note and the one produced by the instrument in question. Players who wish to be able to transpose music written for another instrument so that it can be played on a different instrument need to change the notes depending on the pitch actually produced by the original instruments. For example, a C played on a B-flat clarinet will actually produce a B-flat note. To transpose a B-flat clarinet piece for an instrument like a guitar which plays notes at the written pitch, the player will have to flatten each note by two semitones.
Different instruments produce notes at a different pitch to the one written down in the music notation. This is because they do not always have the required notes to reproduce a song as it is originally written. Instruments such as the alto flute, the clarinet, the saxophone, and the trumpet fall into this group. To play music originally intended for one of these instruments at the correct pitch, the player will have to transpose instruments according to the degree by which they differ from the written pitch.
Many different lists of the different instruments and their difference in pitch from the written notes can be found online. Anybody wishing to transpose instruments should look at these lists and find the instrument they wish to transpose music from. The written note will be displayed, and then the actual produced note will be displayed. Intervals may be used to describe the distance between the written note and the produced note when trying to transpose instruments. A “minor 3rd ascending” interval is two notes higher than the original note — the original note is counted as the first — and is flattened to make it minor.
Each note written down in the piece of music should be changed by the same degree when musicians transpose instruments. If a piece of music written for the horn in F states that a note is a C, it will actually have been produced as an F. This is a perfect fifth below the written pitch, and can be worked out by counting five whole notes down from the original note, remembering to count the original note as one. If a different note appears in the same piece of music, it will have to be altered by the same degree, so a D would become a G. This is achieved by counting down; D is one, C is two, B is three, A is four, and G is five.