On Mon, Sep 29, 2008 at 6:49 PM, D'Arcy J.M. Cain <[EMAIL PROTECTED]> wrote: > On Sun, 28 Sep 2008 16:37:11 +0200 > "Mr.SpOOn" <[EMAIL PROTECTED]> wrote: >> Hi, >> I'm working on an application to analyse music (melodies, chord sequences >> etc.) > > Sounds interesting. Will this be Open Source?
Well, yes, I think. > Have you considered having the object take a key option with default to > 'C' so that you don't have to mark as many accidentals - or, more > correctly, mark actual accidentals rather than always marking the > "black keys?" Well, one of the analysis task would consist in finding a possible tonality from a set of note. Or, more useful, give a set of playable notes over certain given chords. > Couldn't the note class simply have a list of all the notes and have a > simple method calculate the actual pitch? That's not really how it works. There exists just 12 octave independent pitch classes. This means that there is a pitch class C with all possible Cs. There ambiguities with accidentals, because different named notes fall in the same pitch class. The difference is important for the musical theory, because C# and Db belongs to the same pitch class (actually they are the same note, they sounds completely identical -- because on the piano you play them pressing the same key), but in a scale they have a very different role. For example, the interval C F# is an "augmented fourth", because what really matters are the natural note (C and F), and their distance if 4. Then it is augmented due to the #- But the interval C Gb (Gb is the same as F#) is a "diminished fifth". So I can't list all pitches. > def interval(self, lower, higher) > if lower > higher: > # uncomment one of the two following lines depending > # on the behaviour you want > #lower,higher = higher,lower > #higher += 12 > > # could use some error trapping > return self.interval_name[higher - lower] > > Note that lower and higher could be a note object that you have to > convert to integers first. I can't estabilish which note is higher, because all the analysis part is octave independent. Anyway thanks for the ideas. I think itertools is what I need. -- http://mail.python.org/mailman/listinfo/python-list
