[Smt-talk] Passing and Neighboring 6/4s

[Dmitri Tymoczko]

On Jan 19, 2010, at 12:46 PM, Stephen Jablonsky wrote:

> Don't forget I-V6/4-I6.

Actually, V6/4 is a great chord to think about.  The chord is much,  
much rarer than you would expect from reading harmony textbooks.  Bach  
almost never uses it (preferring viio6), and it is also exceedingly  
rare in Mozart.

For instance, here are some interesting chord-progression counts from  
the Mozart piano sonatas:

	I -> V6/4 -> I6 appears 4 times (including the retrograde  
progression, I6->V6/4->I)
	IV6 -> I6/4 -> [IV or ii6 or ii6/5]: appears 51 times (including the  
retrograde progression)

In other words, the second progression is more than *twelve times*  
more popular than the I->V6/4->I6 -- even though I->V6/4->I6 is  
harmonically unobjectionable and uses textbook-approved "passing 6/4"  
voice leading.

I take a few lessons from this:

	1. If you want to imitate Mozart, stay away from I->V6/4->I6; use I- 
 >V4/3->I6 (which appears 110+ times) or I->viio6->I6 (40 times)  
instead.

	2. "Passing 6/4"s are a very particular phenomenon, at least in  
baroque and classical music: we're really talking about a specific  
progression, IV6->I6/4->[IV or ii6 or ii6/5] rather than some more  
general type of progression that comes in a variety of flavors.

	3. Music professors and textbook authors have strong, but not  
necessarily reliable intuitions about what happens in tonal music.   
For instance, Aldwell and Schachter write: "Of the various types of  
passing 6/4's the most important is V6/4 connecting I and I6."  This  
is false, at least if "important" is taken to mean "common" and if  
Mozart's Piano Sonatas are taken as representative.  To me it's a bit  
embarrassing that one of the leading textbooks can be so flatly wrong  
about such a basic matter.

	4. When thinking about tonal harmony, it's probably worth  
distinguishing the practices of Bach, Mozart, Brahms, etc.  Things  
that are reasonably common in Brahms (like I-iii-V) are pretty rare in  
Mozart.  It's not clear that there is one set of rules that applies to  
every composer 1700-1900; instead, we have a variety of similar, but  
not entirely congruent, musical styles.  We could stand to be a little  
clearer, when teaching students or writing textbooks, which  
conventions we have in mind.

All of this is making me think that it might be worth writing a  
harmony textbook that was based on actual data.  The ones we have are  
basically reliant on the intuitions of the authors.

DT

Dmitri Tymoczko
Associate Professor of Music
310 Woolworth Center
Princeton, NJ 08544-1007
(609) 258-4255 (ph), (609) 258-6793 (fax)
http://music.princeton.edu/~dmitri