Voice leading is important. There is no doubt about it. But why? Why should we spend the time to become familiar with this seemingly unconnected side of theory? How many people have come out of college music courses, taking several semesters of elementary harmony and voice leading, but have been unable to use it effectively in composing? A lot, and I think its for several reasons.
Why Voice Leading Doesn’t Stick
Let’s look at why you may not fully internalize voice leading after learning it:
- You don’t believe it is applicable to your style of music making. This could be that you don’t compose, and so you don’t think you even need to know this. Or maybe, you like to write rock tunes, and voice leading is something that Bach did, so its not really applicable. Whatever your reason, you have put up a mental barrier towards acceptance.
- You think there are too many pointless rules. There are quite a few rules to voice leading. Rules about the direction of voices; what can be doubled and what can’t; incorrect chord progressions. Yeah there are quite a few, but the rules have a purpose and I am going to spell that out in the next section.
- You don’t get past the beginner’s stage. Every time you learn something, you must repeat it enough for it to become automatic. When it is a new skill, the amount of brain power it takes to use it is immense… especially something as complicated as voice leading. But if you put in the time, you can internalize it, and use that left over brain power for other activities. This is one of the main reasons some people are not good at musical analysis. Its because your eyes move faster than your brain, and you get behind. Eventually you are just looking at a blob of ink on the page, and wondering where you lost your place, or when is it lunch time.
So what can we do about this? First let’s take a look at why voice leading is important.
The Purpose of Learning Voice Leading
If we take a few steps back in history, we can get a firm grasp on why voice leading is important.
In the dawn of musical time… all we really had were voices and things to bang on. Sticks, stones, basic drums made of hide. Maybe somebody fashioned a flute out of bone, or a primitive trumpet out of an animals horn. Things were simple. Ug didn’t really care about parallel 5ths. In fact, Ug didn’t really know what 5ths were, let alone, Weitzman Regions or parsimonious voice leading (but I digress).
A few years down the line, people started to codify the way sounds came together to make enjoyable music. Most of this music was still sung, and so when we started to write it down, we called it voices.
More and more time goes by, we find out that more than one voice at a time sounds good they are singing different notes, and certain things start to become commonplace. Certain intervals become “consonant,” and others “dissonant.” Diabolus in Musica…
But the thing about the human voice, is that it is not “exact.” If you’ve ever sang in a choir or a group that has to sing harmony, you realize how easy it is to slip out of tune, or even completely off of your note, and boom, your out. You don’t know what to do. You hold your finger to your ear… laa.. la. cough.. laaaaa… there it is! LAAAAAA.
The people writing and singing the music started to notice certain things.
- Leaps are harder to sing then steps.
- If you have two or more voices, and you want them to sound like two different parts, then contrary motion sounds better because it makes them sound more separate. Parallel motion makes them sound as one, sometimes, if it is in octaves or even 5ths, you cannot tell that two pitches are being sounded.
- Crossing of voices makes it difficult to sing and keep track of different parts.
The Cognitive Reasons for Voice Leading
The following information comes from a paper by David Huron called Tone and Voice: A Derivation of the Rules of Voice-leading from Perceptual Principles. If you want a very in depth look at the subject, I recommend reading it, as it is very thorough. This is just a summary of the principles.
The rules of voice leading have a certain goal in mind. This is important to remember, as sometimes, the goal of voice leading is not the goal of the composer. So for the naysayers out there, saying that “parallel 5ths sound good, and Debussy used them,” I get it. You want to be your own composer. To me its just a cop out, and you’ll be much better off understanding and being able to use them properly. As my Dad always told me in reference to bad movie music:
You’ve got to know the rules, before you can break them. And this guy clearly doesn’t know the rules… Dad
So what are these goals? To create two or more, concurrent yet perceptually distinct “parts” or “voices.” Good voice leading maximizes auditory streaming.
What is Auditory Streaming
The idea of auditory streaming comes from a psychologist named Albert Bregman. We’ll call him Al. Al figured out that the way we hear things is very specific. You see, we have a problem. This problem is that we have only two ear drums, and all of the sounds we hear hit this one little spot in our ear. So our brain has to do something to separate these sounds out and make them useful. How does this happen?
In comes Al to the rescue. Al figured out that our brains have the ability to separate, or integrate these sounds into what are called “auditory streams.” Several factors go into whether we hear something as integrated or segregated.
- Timbre
- Interval distance (pitch)
- Time span between onset of pitches
This site has a good example of how auditory streaming works.
So with auditory streaming understood, how does voice leading apply?
Maximizing Auditory Streaming
David Huron follows the goal with two corollaries (a corollary is just a statement that follows from another statement).
- Effective voice leading requires clear auditory stream integration within each of the individual parts.
- Effective voice leading requires clear auditory stream segregation between each of the concurrent parts.
This makes sense from a musical basis, as segregating out the different auditory streams gives your clearly different parts. But how do we get there from a perceptual basis, and how do they apply to the rules of voice leading.
The Summarized Rules of Voice Leading
Below is an exact quote from Huron’s paper. These are the rules that he as put out there for voice leading. I think they sum it up very well, and will give us a great starting point for grouping our own rules that we learn from textbooks and courses. I put these up there first because I want you to realize where he is basing his research from. Later on, each of these rules will be explained using the six perceptual principles he lays out in the paper.
- Registral Compass Rule. Harmony texts begin by specifying the pitch range for harmonic writing. Students should write in the region between F2 and G5. Although this region corresponds to the combined pitch range for typical male and female voices, it is noteworthy that students of harmony are encouraged to write in this region, even when writing purely instrumental music.
- Textural Density Rule. Harmony should be written using three or more concurrent “parts” or “voices.” The most common harmonic writing employs four voices set in overlapping pitch regions or tessituras: soprano, alto, tenor, and bass.
- Chord Spacing Rule. In the spacing of chordal tones, no more than an octave should separate the soprano and alto voices. Similarly, no more than an octave should separate the alto and tenor voices. In the case of the bass and tenor voices, however, no restriction is placed on the distance separating them.
- Avoid Unisons Rule. Two voices should not share the same concurrent pitch.
- Common Tone Rule. Pitches common to consecutive chords should be retained in the same voice or part.
- Nearest Chordal Tone Rule. If a part cannot retain the same pitch in the next sonority, the part should move to the nearest available pitch.
- Conjunct Motion Rule. When a part must change pitch, the preferred pitch motion should be by diatonic step. Sometimes this rule is expressed in reverse:
- Avoid Leaps Rule. Large melodic intervals should be avoided.
- Part-Crossing Rule. Parts should not cross with respect to pitch.
- Part Overlap Rule. No part should move to a pitch higher than the immediately preceding pitch in an ostensibly higher part. Similarly, no part should move to a pitch lower than the immediately preceding pitch in an ostensibly lower part.
- Parallel Unisons, Fifths and Octaves Rule. No two voices should move in parallel octaves, fifths, or unisons. In the case of many theorists, a more stringent version of this rule is used:
- Consecutive Unisons, Fifths and Octaves Rule. No two voices should form consecutive unisons, octaves, fifteenths (or any combination thereof) — whether or not the parts move in parallel. Also, no two voices should form consecutive fifths, twelfths, nineteenths (or any combination thereof).
- Exposed (or Hidden or Direct) Octaves (and Fifths) Rule. Unisons, perfect fifths, octaves, twelfths, etc. should not be approached by similar motion between two parts unless at least one of the parts moves by diatonic step. Most theorists restrict this rule to the case of approaching an octave (fifteenth, etc.), whereas some theorists also extend this injunction to approaching perfect fifths (twelfths, etc.). Most theorists restrict this rule to voice-leading involving the bass and soprano voices; in other cases, exposed intervals between any pair of voices are forbidden.
In future posts, I’ll be showing examples of all of these rules, and hopefully, you will get something out of it.








