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:

1. 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.
2. 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.
3. 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).

1. Effective voice leading requires clear auditory stream integration within each of the individual parts.
2. 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.

I’ll be going through each species and trying tie in these ideas directly with what I am learning from Fux and Jeppesen.

Stay tuned!