Hi,
I have a few questions regarding four part writing. Walter Piston presents two "rules of Thumbs" in the first chapter of voice leading in the major mode. Then he proceeds to teach the various means of voice leading such as crossed voices, direct 5th/8vs and bad parallels. What confuses me is this, are these rules of thumb actual laws? I've never heard of them, nor have I witnessed an equivalent of them in any text regarding this subject. He moves on to the aformentioned rules of four part writing after talking about ways of departing from the rules of thumb. Can anybody shed some light on this for me? Those rules of thumbs are:
1.If two triads have one or more tones in common, these common tones are usually repeated in the same voice, the remaining voice or voices moving to the nearest tones of the second chord.
Exception: In the progression II-V, when the fourth degree is in the soprano of II, it is customary not to repeat the common tone, but to move the upper three voices down to the next available position. (This motion may, but need not, be used when the fourth degree is in the alto or tenor.
2.If the two triads have no tones in common, the upper three voices move in opposite direction to the motion of the bass, but always to the nearest available position.
Exception: In the progression V-VI, the leading tone moves up to the tonic, while the other two voices descend to the nearest position in the chord. The third, rather than the root, is doubled in the triad on VI. This exception always holds true when the leading tone is in the soprano of V; when it is in an inner voice, either the rule or the exception may apply.
Edit: I would just like to add, on the subject of doubling? I read that the rule is to double the root. In the vast majority of instances, I find that this creates no problems. But in the event that it does, is it customary to double something else? Preferably the third? And what constitutes a better move from another in the same progression, as Walter Piston's text shows several examples of the same progression in different positions and makes it know that x is more satisfactory than y, without stating why.
My appologies in advance for my ignorance on the subject. Any help will be gratefully received.
