Bridget Mermikides explains the principles and practice of four-part harmony, and how understanding it can make you a more rounded musician and more knowledgable guitarist.
The history of four-part harmony, based on the simple idea of four voices singing in harmony, is the cornerstone of Western music and its influence can be heard across the centuries, from Bach to The Beatles and far beyond. It can be found in countless chorales, piano pieces, brass, wind or string quartets, songs and even in the basic concept of chords themselves. A complete study of four-part harmony would take years to complete, but looking at its main principles is a fascinating and extremely worthwhile thing to do.
First of all, most courses on four-part harmony – aka four-part writing, SATB (Soprano, Alto, Tenor, Bass) etc – might seem like a series of rules to memorise and strictly follow, in order to avoid ‘doing it wrong’. The reality is that these ‘rules’ actually emerged from the pursuit of musical expression rather than the other way around. Once you understand the basic aims and principles of four-part harmony, it becomes easier to absorb and appreciate these ‘rules’ not as abstract ideas, but as evolving from core musical principles. These principles might be summarised as…
Singability: Every part must be singable by a human, and this has implications on the range and contour of each of the four voices. This means that the range of each voice is well defined and most melodies are confined to same-note, step-wise (scale) motion or well-considered leaps (chord tones).
Independence: Each voice should have its own independent melody. The wonderful effect of good four-part writing is that harmony emerges from multiple simultaneous melodies rather than as basic block chords. When two or more voices move together with too much similarity, this jeopardises that effect.
Musical logic and balance: Inherent in the craft of four-part harmony is a beautiful musical logic, and a sense of tension and release that the listener can appreciate. This can be found ‘vertically’, in that the chords produced have a balanced use of dissonance and consonance. Tense chords will have a tendency to resolve to chords that sound more ‘seated’ – these generally start and end musical phrases. Each chord will be neither bland, nor too esoteric for the style. Each voice will also have a ‘horizontal’ logic (which
The reality is that the rules of harmony emerged from the pursuit of musical expression, rather than the other way around.
actually helps them be singable), in that certain tones will have a tendency to resolve in certain directions, and leaps are balanced, in that you won’t hear too many consecutive leaps up or down.
These three basic principles explain all the ‘rules’ or guidelines you might hear. You might, for example, have heard of the avoidance of parallel octaves in four-part writing. Why would this be a problem? Because two voices that move together in octaves sound like one musical line, thus jeopardising the independence of the voices in the musical passage.
You might also hear that you should never double the 7th note of the key (known as a leading tone). Why? Because a leading tone has a strong tendency to resolve up to the tonic, and so each voice singing a leading tone will either move together (making them no longer independent) or if they don’t, then one of the voices is likely to not sound logical. And that’s why such things as parallel octaves and doubled leading tones are rare – because they are likely to jeopardise a musical principle (and not sound good), not because they violate some arbitrary ‘rule’. That said, there are examples – even from such masters of four-part harmony as J S Bach – of ‘forbidden’ parallel motion and the like. Why? Because, at that moment, other musical imperatives of melody and narrative were more important than the three principles. It’s music first, and the ‘rules’ should be understood for what they are – merely stylistic guidelines.
Now let’s focus on some techniques of four-part writing through a number of examples arranged for the guitar, which will help you understand, arrange and compose a wide range of music. We’ll encounter some ‘rules’ on the way, but they will all be in the service of ‘singability, independence and musical logic’. You’ll get the most from these if, for each example, you learn to sing along each part (if you can reach it) or, better still, do so with other people.