Subtonic issues

[GoogleCodeExporter]

In chords.py I have two question marks

1. Shouldn't vii7 return subtonic7?

def vii7(key):
    return subtonic(key)

def VII7(key):
    return subtonic7(key)

2. Isn't subtonic being confused with leading tone?
subtonic7("C") => ['B', 'D', 'F', 'A']
Shouldn't it be a whole step below tonic and thus ['Bb','D','F','Gb']?

http://books.google.com/books?id=bJdrYYBJFnoC&pg=PA157&lpg=PA157&dq=subtonic+tri
ad&source=bl&ots=k_bo1XKhKt&sig=saXOomaRLG1RjfkyoJfql_ZF1hI&hl=en&sa=X&ei=MTM1Uf
ChO-rr0QG4xoDgBg&ved=0CGIQ6AEwCA#v=onepage&q=subtonic%20triad&f=false

Original issue reported on code.google.com by andreas....@gmail.com on 4 Mar 2013 at 11:58

[GoogleCodeExporter]

This change in chords.py will fix the issue:

def subtonic(key):
    """Return the subtonic chord in key.

    Example:
    >>> subtonic('C')
    ['B', 'D', 'F']
    """
    return triads(intervals.minor_third(key))[4]

def subtonic7(key):
    """Return the subtonic seventh chord in key."""
    return sevenths(intervals.minor_third(key))[4]

Original comment by OrtalisM...@gmail.com on 16 Apr 2013 at 5:58

Attachments:

• chords.py

[GoogleCodeExporter]

Oh, I hadn't added a leading_tone() or lead_tone7() functions before, these 
should work. If leading_tone7() is passed a minor key (lowercase) it will give 
a diminished 7th chord and if it is passed a major key it will give a half 
diminished 7th, so I believe the is how it should be.

I tried to fix the corresponding roman numerical chord functions too, but they 
might not be correct. I would have thought that lowercase roman numeral should 
give the minor (or diminished) chord (depending on the degree) while uppercase 
should give major, but this is not the convention in the file.

Original comment by OrtalisM...@gmail.com on 17 May 2013 at 6:51

Attachments:

• chords.py