Thursday, September 8, 2011


In connection with harmony and form I have several times mentioned the cadence. Lots of people know what I am talking about, but others might not so let me talk about the cadence a bit. It is a very useful exercise to reexamine the fundamentals of music from time to time. Composition in the Classical Era had, if not unbreakable rules, then certainly procedures that were followed without fail. One of these is that each piece and significant section of a piece had to end with a cadence. In fact, the cadence defined the parts of the piece. For an overview and some examples, have a look at the Wikipedia article on the cadence.

Cadences come in varying strengths. The strongest, called a Perfect Authentic Cadence is required to end a piece--or even a significant section of a piece--in the Classical Era. Even after many years as a performer I was surprised to hear this stated so firmly by a theorist and even more surprised to discover he was correct. It is simply not the case that composers often used cadences to end pieces in the Classical Era--no, pieces HAD to have a solid cadence at the end.

A cadence is more than mere punctuation. Every sentence in prose writing normally ends with a period, but in music phrases may end in various ways, sometimes with, sometimes without a cadence. Also, cadences come in varying degrees of strength from ones that are very solid indeed, to ones that are deceptive, leading not to the home chord or tonic, but to some other chord. In those cases the cadence does not close off the music, but leads it on. Cadences in some form or another have been used ever since mentioned by Guido of Arezzo around 1026. We can see how cadences work in just one phrase of a piece by Haydn. Here is the opening of his Piano Sonata in E flat major:

click to enlarge

Here are the first nine measures of the piece. The first phrase ends on the first beat of the ninth measure, which is also the beginning of the next phrase. Now look at the smaller sections. The first two measures begin and end with an E flat chord, but there is no cadence. The next three measures move to a B flat chord, known as the dominant and with some faster moving ideas, end up, in measure six, on a new chord: C minor. Measure eight ends with two separated chords, an F minor followed by a B flat with an added 7th (the A flat note). These two chords, followed by the E flat chord that is the first beat of measure nine, create a Perfect Authentic Cadence which is the dominant (B flat, prepared by the F minor chord) followed by the tonic (E flat) both in their strongest form. In microcosm, this is how classical harmony works. No matter what the first chord might be, until we have the full cadence of measure 8 to 9, we have not defined a tonality. Here is a performance of the piece so you can hear how this works:

The full cadence, ending the first phrase and defining the tonality, occurs at the 20 to 22 second mark. What happens in measure six, at the 14 second mark, shows the subtlety of the system. Here, where we might expect an E flat chord, we get instead a C minor chord. C minor is closely related to E flat, but still different. Going to C minor expands and opens out the phrase. These sorts of things: presenting a tonality, but delaying confirmation, expanding to closely related areas and finally confirming the tonality--all these are typical harmonic devices and they all depend on either using a cadence in a strong or weak form, or on delaying the cadence. Not only a single phrase, as here, but entire movements several minutes long, are constructed with these same devices.

If you learn to listen for cadences, it will clarify the musical form for you.


Anonymous said...

Jazz modulations can be so quick that, with roots and 5ths typically omitted, the quickest way to spot the key is to look for the dominant 7th leading to it (or its tritone substitution). So yes cadences are hugely important!

What's also interesting is how many of these basic musical concepts are not really "contingent" but have to do with physics. A perfect cadence is what it is because, at the end of the day, 3/2 is the simplest fraction bigger than 1. Much of modern music (and free jazz) is trying to reject these constraints as though there were just conventions. But they are not. We do not like C-E-G because we've been socially conditioned to like it. We do because 3/2 and 5/4 are among the simplest fractions. And the reason we "like" simple fractions is not a matter of taste. It's because they create resonances. We like CEG for the same reasons tylenol relieves headaches: it's physiological and, fundamentally, has nothing to do with will or culture. Now where culture plays a role is in how quickly we might get bored with too much CEG and so great music is the art of venturing in and out of the "natural" zone. But to pretend there's no such thing as a natural zone is absurd.

Bryan Townsend said...

Yes! There is a kind of evolution in harmony. In the earliest period--say, the organum of the 12th century--all intervals except the 5th were considered dissonant to some extent. After a time the third was admitted, though originally only the major third. This is why many pieces in minor even up to the 17th and early 18th century ended with a major chord instead of a minor one: the so-called "tierce de Picardy". In the classical period material presented in keys other than the tonic needed to be recapitulated in the tonic. With Chopin, this ceases to be the case.

You are quite right in saying that there are sound reasons, based in physics, why some intervals sound dissonant and others consonant. But over time, the degree of acceptable dissonance became broader. Many pieces in jazz end with a chord containing a major seventh chord, which is a fairly strong dissonance.

For a long time stronger and stronger dissonances were used until finally, with the adoption of completely atonal music in the 1920s, consonance was no longer a goal. But listeners could no longer find their way! As Richard Taruskin was pointing out in that long quote I included in my last post on harmony, composers now are re-discovering consonance!