Why Use C-Flat?

Note: I’ve noticed that this post looks just fine in most browsers, but Internet Explorer may have a hard time with the flat and sharp symbols in the text.

a music staff showing enharmonic equivalents

Not misfit notes…just misunderstood.

A Little Background

To understand why C♭ is such an odd note, you have to understand a little about musical pitches, and the best way to describe this is with a keyboard. On a piano keyboard, there are black keys and white keys. The white keys are usually whole steps apart, and they get names like A, B, C, D, and so forth until you get to G. The black keys exist at half steps between those white keys; notes like G♯ and D♭ exist on the black keys.

piano key board three octaves

Notice the space between E & F and B & C, however. There are no black keys between these notes – meaning they are already half steps apart. That means an F♭ is an E, and an E♯ is an F. C♭ is B and B♯ is C. (These are called enharmonic equivalents for those of you seeking to expand your vocabulary. They produce the same tone while written differently.) The question remains, however, that if these are essentially the same notes, why bother?

Learning to Spell

One explanation for the use of enharmonic flats and sharps boils down to spelling the chord to which it belongs. The basic triadic chord for A is spelled A-C-E. An A major chord is spelled A-C♯-E, and you lower the C♯ to C to make the chord A minor. If your chord is an A♭ major chord, then you would lower everything by one half step and spell it A♭-C-E♭. Lowering the third to create an A♭ minor chord would necessitate the use of a C♭ if the triadic spelling is to remain intact. This also applies to the rare usage of double-flats and double-sharps in specific keys.

a progression from A major to A♭ minor, illustrating the use of C Flat in the last chord.

In order: A major, A minor, A♭ major, A♭ minor.

If you were to substitute the C♭ with a B (its enharmonic equivalent), it would disrupt the triad spelling and create a very unusual-looking chord.

A flat minor spelled with a B instead of a C flat

You might still ask, “What does it matter so long as both spellings sound the same?” Yes, they do sound the same. So do their and they’re, yet we wouldn’t advocate interchanging them in writing because of their phonetic similarities. Correct spelling in music matters as much as it does in prose.

Where Are You Going?

The other reason for using these unusual notes is a bit more subtle and a little psychological. It has to do with voice leading — the way notes move from one pitch to another. In any given key signature, when you raise a pitch by using an accidental, you are creating upward voice leading. That pitch should continue moving upward. The opposite is true if you lower a pitch using an accidental.

I’m going to stay in A♭ major for the next couple examples.

a musical passage with misleading voice leading

Pay attention to the notes in the box. By adding a natural sign to the B on the second beat of measure two, we create an upward leading phrase. The next pitch, however, is lower, disrupting the flow of the voice leading. It’s the musical equivalent of saying, “I am going to a movie yesterday.” I am going leads the reader to expect a given time frame — later, tomorrow, next week etc. The word yesterday disrupts that expectation. Resolving a raised pitch downwards (or a lowered pitch upwards) creates the same level of cognitive dissonance.

Instead, the passage should have been written this way:

the same musical passage with better voice leading

Now, using the C♭, the overall chord will be spelled correctly when put in context of the other parts, and the performer sees correct leading. The lowered C naturally will draw the performer in a descending pattern. Likewise, the upward leading of E♯ and B♯ become very important in some minor scales and a few modal scales.

Coda

It may seem a small thing, but notes like C♭ and E♯ (as well as those double-flats and double-sharps I didn’t include in this post) serve a purpose in writing music correctly. Both in voice leading and in chord spelling, it may be necessary to use a note whose enharmonic equivalent seems simpler at first blush. Despite their auditory sameness with those equivalents, these misunderstood notes are important to composing with musical integrity.

featured image from Haydn’s String Quartet In E-flat Major Opus 33, No. 2 ‘ The Joke ‘

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