Enharmonic equivalent key signatures

Enharmonic equivalent key signatures are keys with different names that include the same pitches, such as C major and D major. Dorico Pro follows the convention for transposing to keys with the same type of accidental as the previous key, except where the enharmonic equivalent key signature has fewer accidentals.

When transposing selections of notes, Dorico Pro prefers keys with the same type of accidental as the previous key signature. When choosing key signatures for transposing instruments, Dorico Pro prefers key signatures with the same type of accidental as the current concert pitch key.

However, there are some instances where you might prefer to transpose to a key with a different type of accidental as it has fewer accidentals than the enharmonic equivalent key. For example, C major has seven sharps, whereas the enharmonic equivalent key of D major only has five flats. This means the player has to remember the accidentals for fewer notes.

Transposing to an enharmonic equivalent key with fewer accidentals can have the added benefit of improving readability by avoiding double sharps or double flats. For example, transposing music from F to G requires the leading note to be spelled as an F, but transposing to A instead means the leading note is G.

Figure 1. G major requires a double sharp leading note
Figure 2. A major, the enharmonic equivalent to G, does not require a double sharp leading note

By default, Dorico Pro selects an enharmonic equivalent key signature if it has fewer accidentals. You can change this setting in each flow independently.

How key signatures affect transposing instruments

If there is a key signature in the full score, it is transposed for a transposing instrument by the same degree as the transposing interval for the instrument. For example, in a project in E major, a B clarinet part has a key of F major, as a B clarinet sounds a whole step (tone) below its notated pitch.

Instruments that do not show a key signature

Some instruments are accustomed to seeing no key signatures in their parts, no matter the overall key of the piece. These instruments include timpani, percussion, horn, trumpet, and sometimes the harp. If you have input the No key sig version of these instruments, then no key signature is shown in their parts, even if they are a transposing instrument, such as horn or trumpet.

You can still transpose music in the staves of these instruments, but they show accidentals as necessary, instead of showing a key signature.