My main question is in the title above.
Chords in Common Practice Style only have three notes, so in 4-part harmony (SATB), one note will be repeated.
In music theory, there are a ton of doubling rules. I am wondering if there is an easy way to memorize all of them, because I don't want to always have to look back at my music theory book when writing chorales (I don't have to follow the rules, but I want to).
Here are the list of doubling rules:
- Root position: Best double root
- I, I 1st inversion, ii, IV: Best double root, 5th and 3rd acceptable
- V: Best double root, 5th acceptable, 3rd unacceptable
- viio: Best double 3rd, root and 5th unacceptable
- vi: Best double 3rd, root acceptable, avoid 5th
- VI: Best double 3rd, root and 5th unacceptable
- I, IV, and V first inversions: Best double root (match in soprano), 5th acceptable, avoid 3rd (for I and IV first inversions), and 3rd unacceptable (for V first inversion)
- ii, iii, iv, and vi first inversions: Best double 3rd, root acceptable, avoid 5th
- 2nd inversions: Best double 5th, avoid root and 3rd, root and 3rd unacceptable in a cadential 6/4
- V7 without 5th: Best double root, 3rd and 7th unacceptable
- Augmented and diminished: Best double root, root unacceptable (for viio)
- Altered chords: Altered note unacceptable
- Scale degrees: Best double 1st, 4th, and 5th; 2nd, 3rd, and 6th acceptable; 7th unacceptable
- Root and 3rd only: Best triple root
That is seriously a ton of stuff.
Any help will be appreciated. Thanks.