As you slowly advance in music theory and composition, you will inevitably run into 4-part harmony. This is an important element of the musical language of the Classical masters from Bach, Handel, Mozart, Beethoven and beyond. The concept developed over centuries and is still used to this day.
So what is four-part harmony? Four-part harmony is a traditional system of organising chords for 4 voices: soprano, alto, tenor and bass (known together as SATB). The term ‘voice’ or ‘part’ refers to any musical line whether it is a melody sung by singers, a long note played on an instrument or anything in between.
Here’s a brief example of 4-part harmony from the music of J. S. Bach. Notice that there 2 main aspects to it. Firstly, there are 4 voices and each one is singing a melody. This is the melodic, or the ‘horizontal’, aspect of the music.
Secondly, the four voices are singing at the same time so their notes are combined into one sound. At any one moment, the music consists of 4 voices each singing one note. In other words, the voices are producing 4-note chords. This is the harmonic, or the ‘vertical’, aspect of the music.
In four-part harmony, we deal with both these two aspects at the same time. We get four distinct parts held together by the same chord progression.
What's in this Lesson
Why Four-Part Harmony?
While music for 2, 3, 5, 6 and more voices does exist, 4-part harmony became standard in the musical style of the 17th, 18th and 19th centuries (a period known as the Common Practice Era). The reasons for this are quite practical:
- Four-part harmony developed as tonal music became standard (that’s the musical system of the major and minor keys). As you know, this type of music mainly works with our typical major and minor chords and these chords fit really well into 4 parts. Tonal music and four-part harmony complement each other perfectly.
- Four-part harmony also accounts for the whole range of human voices: from the lowest notes (sung by males) to the highest (sung by females) and everything in between.
Because of these reasons, even instrumental or orchestral music of the time was written with four-part harmony in mind. The orchestral strings, for example, are often treated as a four-part choir: 1st violins on top, then the 2nd violins and violas in the middle, and cellos plus double basses together for the lowest part.
Why do we Learn a Musical System of the Past?
Now before we move on to the basics of four-part writing, why should we even learn a musical system of the past?
The answer to this question merits its own article but in short, it’s because:
- The discipline you get from manipulating musical notes in certain ways according to certain guidelines can be applied to any other musical style. The study of four-part harmony teaches you how music works (by working with aspects such as chord progressions, rhythm and writing melodies). You can then apply your understanding in any way you like in your own music.
- Four-part harmony is part of a continuous line of musical development from the earliest medieval chants to contemporary film music. When you see how music composition developed over time, you get a profound appreciation of how it evolved to fit the needs and purposes of its time. Four-part harmony is an important part of this evolution.
- In addition, learning how composers of the past wrote their music opens it up for analysis and further learning. Earlier we looked at a brief excerpt from a Chorale by Bach (whose music is the standard model for 4-part writing). Thinking about why the composer chose to do things in one way or another provides composition lessons that no book or course can teach us!
Later on in this lesson, we’ll come back to the same Bach example and see what it can teach us about the basics that we are learning today.
How to Write 4-Part Harmony: the Basics
Writing basic 4-part harmony requires some fundamental guidelines for: 1) proper notation, 2) the ranges of the voices, 3) doubling rules and 4) spacing. Let’s go over these one by one.
As we said, 4-part harmony is written for 4 voices: Soprano, Alto, Tenor and Bass (SATB in short). The notation for these is written on two staves: one in the treble clef for the Soprano and Alto parts and the other in the bass clef for the Tenor and Bass parts.
To make the written music clear, the soprano voice must have notes with stems going up while the Alto voice must have notes with stems going downwards. Similarly, the Tenor voice must have stems going up and the Bass voice with stems going down.
Also, the two staves are joined together by a brace, showing that they go together:
Four-Part Harmony Voice Ranges
Here are the ranges of the four voices. More or less, these represent the normal span of human voices and it’s not recommended to go beyond.
Soprano: from middle C to high G
Alto: from G below middle C to C above middle C
Tenor: from C below middle C to G above middle C
Bass: from F below the stave to middle C
Four-Part Harmony Doubling Rules
If basic chords are constructed of three notes but this style of harmony is in four parts, where does the fourth note come from? That’s a good question and a common one too. The answer is in a procedure known as doubling.
Doubling means that one of the notes of the triad is in two voices at the same time (that is, doubled). The G major triad below is rewritten for four parts, with the root G in the Bass and again in the Alto. In other words, the note G is doubled:
The doubled note can go to any of the four voices as long as it is within range.
How do you know which note you should double?
As you advance in your learning, you’ll be able to use a variety of options but the easiest rule to start with is this:
Double the primary notes of the scale you’re in.
The primary notes (also known as the tonal degrees) are the 1st, 4th and 5th notes of the scale.
For example in C major, the tonal degrees are the notes C (the first), F (the fourth) and G (the fifth). These notes are important as they support the tonic (they help establish and maintain the tonal centre).
Now here are all the triads of the G major scale. Notice that there is at least one tonal degree in every chord of the scale. No matter the triad, you’ll always find a tonal degree to double!
The tonic and subdominant chords themselves (the first and the fourth chords) each contain two tonal degrees. Most often, we double the root of these chords but the alternative is fine too.
Notice that all chord-factors (root, third and fifth) are in the chord. In four-part writing, we can sometimes leave out the 5th of a chord but never leave out the 3rd (as that’s where the chord gets its major or minor sound).
Four-Part Harmony Spacing
Spacing refers to how we distribute the notes of the chord amongst the four parts. Questions such as: “Which note should go on top?”, “How far should the notes be?” and “Where can the 5th of the chord go?” are all a matter of a spacing.
Here are 6 examples of the C major chord in a variety of possible spacings. These chords are all correctly written for four parts but since the notes are arranged in different ways, they all sound different. Observe that all versions are in root position (with the root in the bass), with the root doubled and always within the voices’ proper ranges.
Isn’t it amazing how many ways there are of writing the same chord for 4 parts?
In these examples, some intervals are placed close together while some others are wide apart. When the three upper voices (Soprano, Alto and Tenor) are within the span of one octave, they are in what is called Close position. When the tenor and the soprano are further apart than an octave, the chord is in Open position.
Out of the 8 chords of the example above, the chords 2, 3, 5 and 7 are in close position; the chords 1, 4, 6 and 8 are in open position.
The largest distance between Soprano and Alto shouldn’t be more than a perfect octave. A wide interval between these voices leaves an empty space in the middle. Composers of the 18th and 19th centuries tended to avoid this.
For the same reasons, the largest distance between Alto and Tenor is also that of a perfect octave.
This doesn’t apply to the interval between the tenor and the bass voices. Here it can be wider than an octave apart because the bass is resonant enough to support itself.
Four-part Harmony Examples Explained
Now that we know the basic rules, let’s say we have these 4 basic triads in the key of F major that we want to arrange for 4-parts. How do we go about it?
- First, we decide which notes we should double. As we said, we double one of the tonal degrees (the 1st, 4th and 5th notes) of the scale we’re in. In this case, we’re in the key of F major so the tonal degrees are F, B flat and C.
- Next, we have to think about arranging the 4 notes for the 4 voices. Start with the bass notes first.
- Finally, we distribute the rest of the notes amongst the upper 3 voices. With this step we must keep in mind the rest of the rules:
- Notation (2 staves: the top one for Soprano and Alto with stems going up and the bottom one for Tenor and Bass with stems going down);
- Stay within the range of every voice;
- Spacing: keep the Soprano and Alto voices within the span of one octave and the same goes for the Alto and Tenor voices.
Just for practice, here are 2 answers (2 versions) for each chord.
Back to Bach
Remember that example by Bach from earlier? Now that we learned a good few things about 4-part writing, let’s have another look and see what else we can learn from the music.
In these 2 bars, we can observe everything we learned so far (and much, much more, of course). We can see how:
- The notation is clear: we have 2 staves each one with 2 voices and the right direction of the stems;
- Every voice sticks to its range;
- Every chord has a tonal degree doubled (since we’re in G major, the tonal degrees are G, C, and D);
- The spacing of the chords is varied: some chords are in open position and others are in close position;
- As we’ve seen at the beginning of this lesson, the 4 voices maintain a more or less independent melodic line but they’re held together by the same chord progression.
Common Questions about Four-Part Harmony
Now that I know the basics of 4-part harmony, what should I learn next? Once you master the basics we’ve talked about in this lesson, the next step is voice leading. This is another essential topic in harmony and it will teach you how the notes of any one chord can (or should) move to the notes of the next chord.
Where can I use 4-part harmony? Well, four-part harmony is everywhere. Nowadays the traditional type is still used in hymns and arrangements for choir but variations of it are used even more. For example, composers of contemporary classical music and jazz musicians often use some sort of 4-part harmony – they just inject new principles to obtain a fresher, more modern sound. Pop, rock and electronic musicians also make use of 4-part harmony when, for example, there is a lead singer or lead guitar with a 3-part backing vocals or keyboards.
As we mentioned earlier, the orchestral instruments are often treated as 4-part choirs too. The strings, we said, are divided into 1st violins, 2nd violins, violas and violoncellos plus double basses. Same idea goes for the orchestral wind instruments: flute on top, then the oboe, then the clarinet and the bassoon at the bottom. Orchestral music and arrangements doesn’t necessarily mean classical music either – film music and all kinds of genres make use of the orchestra.
But perhaps, the strongest argument in favour of learning 4-part harmony is that it teaches you how music works. Chord progressions, melody writing, bass lines, counterpoint, rhythm, texture and a lot more are all part of the study of 4-part harmony. In addition, having any other number of parts than 4 doesn’t really change that much. The basic principles are more or less the same. Once learned, we can apply these principles anywhere and in any way we like.