Using music21, how can I transpose a pitch down an octave?

If I use p.transpose(-12), flats get changed to sharps:

import music21
p = music21.pitch.Pitch('D-4')
print(p.transpose(-12))

output

C#3

Using music21, how can I transpose a pitch down an octave?

If I use p.transpose(-12), flats get changed to sharps:

import music21
p = music21.pitch.Pitch('D-4')
print(p.transpose(-12))

output

C#3

• python
• music21
• music-notation

• For most practical purposes, C sharp and D flat are the same note. Probably the printed representation of the note is affected by the key signature. – kindall Commented Feb 17 at 23:29
• Try -8 instead of -12 – Starship Commented Feb 18 at 0:37
• @kindall -- a pitch doesn't have a key or key signature, and I couldn't find a way to transpose using a key or key signature (other than perhaps adding the note to a stream and transposing that, and then removing it from the stream and discarding it.) – Jeff Learman Commented 2 days ago
• @Starship -- when a number is used, it's interpreted as semitones. – Jeff Learman Commented 2 days ago
• 1 @JeffLearman I meant -P8 (which you also say is what worked for you) – Starship Commented 2 days ago

1 Answer 1

Instead of -P12, use -P8, like this:

import music21
p = music21.pitch.Pitch('D-4')
print(p.transpose('-P8'))