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Here are a few tips that I have given to my grade 8 music theory students - just some basic pointers and outlines of general principles to keep in mind.
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When Harmonising a given bass line or melody.
One thing to keep in mind when deciding on chord sequences, is that certain progressions are very strong, and if you use them where possible you can’t go far wrong. One example of a strong progression is based on a series of fifths.
Think of the perfect cadence which is V I. A perfect cadence is even stronger if it is II, V, I - and this is a very common way of doing a perfect cadence. Each of those chords are a fifth apart, going backwards. You can continue that cycle even further backwards, going a fifth up from each chord and you can end up with a complete sequence:
I, IV, VII, III, VI, II, V, I.
(Or you can think of it as going up a fourth if you’re going forwards.)
In C Major this chord sequence would be:
C maj, F maj, B dim, E min, A min, D min, G maj, C maj.
So don’t think of the Roman numerals as being up a fourth each time, think of the root of each chord.
You don’t often see this whole sequence uninterrupted in a piece of music, but you will often see chunks of it, and if you’re ever unsure of what chord sequence to do, try working your way backwards from any point that you have managed to fill in the chords (particularly a cadence) and see if going backwards in fifths for a while fits in. (Using chord III in a minor key is awkward because it ends up being an augmented triad, but in this sequence in a major key works well.)
This works so well, because anytime you go from one chord to another and they are a fourth apart going forwards (or a fifth apart going backwards), it sounds a bit like a little perfect cadence on a very small scale, with a resolution each time.
It would be worthwhile playing through the above chord sequence in any key on the piano, just to familiarise yourself with the sound of it.
I, VI, IV, I is another good progression to keep in mind and see if it fits if you’re stuck.
As shown above, II, V, I makes a very strong perfect cadence. The other strong perfect cadence is of course Ic, V, I. Try and use either of these two cadences at the end of a piece where possible. Even better, try and use V7 I at the cadence where possible. Make sure the 7th of chord V resolves downwards onto the 3rd of the tonic triad. And make sure the leading note of the key (or the 3rd of chord V) resolves upwards to the tonic.
In a Ic, V, I cadence, or cadential 6-4, try and follow these rules:
The name cadential 6-4 comes from figured bass. Even if you are not being asked to write figured bass, it is important to understand something about the notes and their relation to the bass. In a Ic chord, you have the fifth of the chord in the bass, and the other notes are a 4th and 6th above the bass. E.g. in C Major you will have G in the bass, with C and E above. In four part harmony you should double this bass, and then you should resolve the 6 onto 5, and the 4 onto 3. So E resolves to D, and C resolves to B. So the figured bass would go: 6-4 then 5-3. The 6-4 acts like a double suspension or double appoggiatura which must resolve downwards onto a root position chord V, then finally finish with chord I.
To further help you choose your chords based on a bass line you’ve been given - try and avoid using 2nd inversion chords too often. Try and save them for cadential 6-4s, or the occasional passing 6-4. In a passing 6-4 you can use chord Vc and the bass moves by step, filling in a line formed by chord I in root position, Vc, then Ib. So if you see a bass line moving in step, see if it would fit this progression (I, Vc, Ib). Otherwise, try and avoid second inversion chords.
Try and make sure that the majority of the chords you choose are the primary triads - I, IV and V in root position or first inversion. Then add other chords here and there (following the series of 5ths idea I mentioned above) to avoid too simplistic a sound. However, be careful to avoid over-complicating things in your effort to make it sound more interesting because you’re worried about it being too simple. Often simpler is better and results in a more unified sound that makes more sense - trying to be too interesting can result in a random sound and a lot of mistakes. Music that is pleasant to listen to (for most people) is based on patterns and repetition. If it is over complicated it is hard to see the pattern.
Chord VII if used should be in first inversion, and generally chord II is better in first inversion too.
Think of the perfect cadence which is V I. A perfect cadence is even stronger if it is II, V, I - and this is a very common way of doing a perfect cadence. Each of those chords are a fifth apart, going backwards. You can continue that cycle even further backwards, going a fifth up from each chord and you can end up with a complete sequence:
I, IV, VII, III, VI, II, V, I.
(Or you can think of it as going up a fourth if you’re going forwards.)
In C Major this chord sequence would be:
C maj, F maj, B dim, E min, A min, D min, G maj, C maj.
So don’t think of the Roman numerals as being up a fourth each time, think of the root of each chord.
You don’t often see this whole sequence uninterrupted in a piece of music, but you will often see chunks of it, and if you’re ever unsure of what chord sequence to do, try working your way backwards from any point that you have managed to fill in the chords (particularly a cadence) and see if going backwards in fifths for a while fits in. (Using chord III in a minor key is awkward because it ends up being an augmented triad, but in this sequence in a major key works well.)
This works so well, because anytime you go from one chord to another and they are a fourth apart going forwards (or a fifth apart going backwards), it sounds a bit like a little perfect cadence on a very small scale, with a resolution each time.
It would be worthwhile playing through the above chord sequence in any key on the piano, just to familiarise yourself with the sound of it.
I, VI, IV, I is another good progression to keep in mind and see if it fits if you’re stuck.
As shown above, II, V, I makes a very strong perfect cadence. The other strong perfect cadence is of course Ic, V, I. Try and use either of these two cadences at the end of a piece where possible. Even better, try and use V7 I at the cadence where possible. Make sure the 7th of chord V resolves downwards onto the 3rd of the tonic triad. And make sure the leading note of the key (or the 3rd of chord V) resolves upwards to the tonic.
In a Ic, V, I cadence, or cadential 6-4, try and follow these rules:
The name cadential 6-4 comes from figured bass. Even if you are not being asked to write figured bass, it is important to understand something about the notes and their relation to the bass. In a Ic chord, you have the fifth of the chord in the bass, and the other notes are a 4th and 6th above the bass. E.g. in C Major you will have G in the bass, with C and E above. In four part harmony you should double this bass, and then you should resolve the 6 onto 5, and the 4 onto 3. So E resolves to D, and C resolves to B. So the figured bass would go: 6-4 then 5-3. The 6-4 acts like a double suspension or double appoggiatura which must resolve downwards onto a root position chord V, then finally finish with chord I.
To further help you choose your chords based on a bass line you’ve been given - try and avoid using 2nd inversion chords too often. Try and save them for cadential 6-4s, or the occasional passing 6-4. In a passing 6-4 you can use chord Vc and the bass moves by step, filling in a line formed by chord I in root position, Vc, then Ib. So if you see a bass line moving in step, see if it would fit this progression (I, Vc, Ib). Otherwise, try and avoid second inversion chords.
Try and make sure that the majority of the chords you choose are the primary triads - I, IV and V in root position or first inversion. Then add other chords here and there (following the series of 5ths idea I mentioned above) to avoid too simplistic a sound. However, be careful to avoid over-complicating things in your effort to make it sound more interesting because you’re worried about it being too simple. Often simpler is better and results in a more unified sound that makes more sense - trying to be too interesting can result in a random sound and a lot of mistakes. Music that is pleasant to listen to (for most people) is based on patterns and repetition. If it is over complicated it is hard to see the pattern.
Chord VII if used should be in first inversion, and generally chord II is better in first inversion too.
General guidelines about doubling notes of chords in four part harmony.
Because triads consist of three different notes, when writing four part harmony, one of these notes has to be doubled in each chord. Be careful about which notes you choose to double.
- For root position chords double the root or 5th.
- For first inversion chords double anything - except in chord V - don’t double the 3rd of chord V because that’s the leading note of the key which should be resolved onto the tonic, and therefore can result in consecutive octaves.
- For second inversion chords double the 5th (the bass).
Be careful with doubling 3rds:
- In a minor triad within a major key, the 3rd can be a good note to double because it is one of the primary notes of the key.
- It is best to avoid doubling the 3rd of a major triad (except in this example - chord VI in a minor key - you can double the 3rd because it is the tonic).
- Do double the 3rd of a diminished chord (and put the diminished chord in first inversion).
If you need to triple something, triple the root of a root position chord.
When writing an incomplete chord, do not omit the root or 3rd.
When writing an incomplete chord, do not omit the root or 3rd.
Avoid consecutive 5ths and octaves, and use good voice leading.
Good part writing (and avoiding forbidden consecutives) always takes priority over doubling rules, so if you need to break a doubling rule to avoid a parallel 5th or 8ve, do so.
Some tips about part writing:
Some tips about part writing:
- Don’t cross parts.
- Soprano and alto shouldn’t be more than an octave apart.
- Alto and tenor shouldn’t be more than an octave apart.
- Tenor and bass can be more than an octave apart.
- Within each part, try and move in step or stay on the same note where possible. This results in a smoother melodic line.
Melodic and smooth part writing can help to avoid a lot of parallel octaves and 5ths.