Why Are Parallel Fifths Bad Voice Leading?

I recently posted a music theory puzzle of a Bach chorale excerpt which contains parallel fifths. I was reminded that some music students may not understand why parallel fifths are considered “bad.” In fact, a great deal of contemporary music uses parallel fifths and to our modern ears they don’t usually sound wrong.

The usual answer is that it “destroys the independence” of each voice, which is true. However, there are also some practical reasons for avoiding parallel fifths in compositions for a cappella voices – it’s hard to sing. ComposerOnline put together an nice video presentation that demonstrates this.

There are also some historical reasons why Baroque Era composers began consciously avoiding parallel fifths. Beginning around the 8th or 9th century polyphony (the idea of using multiple melodic lines together, rather than just unison voices or voices with drones) developed. The religious chants were sung in monasteries by both men and boys in octaves already, so it seems obvious in retrospect that they might also sing them in parallel fifths. This is known as “parallel organum.” David W. Barber describes organum in his book, “Bach, Beethoven, and the Boys: Music History As It Ought To Be Taught.”

Gregorian chants developed into something called organum, which was all the rage of the ninth to 12th centuries. In its simples form, this consisted of singing the same Gregorian tune as the monk beside you at the interval of a perfect fourth or fifth.* This is harder to do than it sounds, and requires the kind of concentration that monks are especially good at.

* Barber’s footnote reads, “It’s not worth explaining why fourths and fifths are called perfect. Just take my word for it.”

Parallel organum later evolved into “free organum,” although it still frequently used parallel fourths or fifths between the two voices. It’s quite a distinctive sound. Here’s an example.

By 1600 ( early Baroque Era) the sound of parallel motion had started to sound old fashioned. Even in instrumental music, which doesn’t have the technical difficulties writing for voices have with parallel motion, composers avoided the use of parallel fifths and octaves. When they were used, they were sometimes used to symbolize something rustic or old fashioned, such as in Beethoven’s 6th (“Pastoral Symphony”).

It’s not until the 20th century when composers began to start using parallel motion with more frequency. It’s now a sound that is ubiquitous in many styles of music. I find it interesting that a musical sound can go from 5 centuries of extensive use to 3 centuries of avoidance, to being used frequently again. Not to mention musical styles other than “western European art music” that use parallel motion all the time. Regardless of your stylistic interests, both the use and avoidance of parallel fifths is something that is worth learning about. The distinctive sound of parallel fifths still has an ability to elicit a powerful reaction on us.

Jake

It’s interesting that parallel fifths are hard to sing, but I don’t believe that this difficulty has anything to do with the reason musicians in the rennaisance and boroque periods avoided them in counterpoint. The “…usual answer, that it destroys ‘the independence’ of each voice,” is much more to the point. Voices moving in parallel fifths or octaves sound like the same voice, but with a different timbre. So, if two voices suddenly start moving together in fifths or octaves the effect is that you lose a voice and change the sound of one of the voices. This doesn’t happen with parallel thirds or sixths because these intervals will constantly shift between major and minor thirds or sixths, which breaks up the sense of a single voice.

Of course, there is nothing wrong with using parallel fifths or octaves if that is the effect you want, but that was not the goal of classical counterpoint, in which the whole point is the interplay between the individual voices.

Actually, organists make use of the sound of parallel fifth motion when they pull a stop called the “quint” (and some other stops, too). The quint adds the sound of a pipe that is a perfect fifth above the fundamental note being played. This changes the timbre of the note, but the note is still heard as the fundamental tone. (Actually, the quint adds a pipe that is a 12th, or an octave and a fifth, above the fundamental; but for this purpose, it is equivalent to a perfect fifth.)

David Batchelor

I imagine that with the Martin Luther reformation going on at this time, composers of the Baroque finally felt it acceptable to God to stray from the ancient sacred traditions of organum-type polyphony. However, I don’t think that is enough of a reason to completely rule out the use of parallel (perhaps better stated as consecutive) 5ths. Some of us may argue that parallel 5ths stand out from the texture when written in a Bach-style 4-part chorale. I have experimented with my theory and aural skill students on occasion to see if it is generally obvious when a parallel 5th is present in the chord progression. Each time, I have concluded that they are very hard to hear unless they occur between the soprano and bass voices. Even then, it takes a talented ear to catch them.

So, why avoid them so diligently? The argument for maintaining independence between voices seems to be the most convincing. Our brains group things together when they are similar enough (search Gestalt theory online for the psychology behind this). As Jake says above, when an organist adds pipes to color a key on the manuals (keyboard), all that is being done is the addition of intervals above or below the original pitch. It may seem apparent to our ears that multiple tones are sounding when the switch happens, but after a while, the sounds meld as one. In Gestalt theory, that’s called grouping. So, it would make sense to some degree that two voices would lose their independence if moving in parallel motion with each other, especially if their timbres are alike. For that moment, the two would sound like a single voice, but with a new timbre.

For my second however, we should remember that the theory we use to describe Baroque music did not exist in the 17th and early 18th centuries. It was developed after the fact by theorist-composers already composing with those rules in mind. (See the treatise on music theory by Jean-Philippe Rameau.) The avoidance of such intervals was already well in practice in the Renaissance period of music with composers like Palestrina and Des Prez. It seems to have grown out of a general agreement and tradition to avoid them. We avoid them today in theory classes only to learn the style we are studying, which is theirs and Bach’s and Beethoven’s style. It enables us to both appreciate and understand their art and their craft.

Luigi Demeticci

It must also be considered that the harmonics of the pitches in consecutive perfect intervals affect the sensation of over-simularity, and cause a block effect to the texture of the harmony created

Keith R. Starkey

Parallel fifths are NOT bad; they are neutral.
They are to be used when a composer wants a particular sound.
They are not to be used when a composer does not want that particular sound.

We need to be respectful to the old cliche: rules are meant to be broken.
It’s quite subjective, at least in more modern times of music.

Dave

Thanks for your thoughts, Keith. As you can see from what I wrote above, I don’t believe parallel 5ths are “bad,” but wanted to muse on the historical and practical influences.

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