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It's time now for a more advanced look at chords, their functions, and how to write chords for several parts.
Let's briefly remind ourselves about this word "chord", and the difference between a chord and the related term "triad".
A chord is the general name given to any collection of notes sounding together, and a triad is therefore also a type of chord, being three specific notes sounding together.
While you can say "a triad is a chord", it is incorrect, however, to say that "a chord is a triad", because a chord can by a collection of any three notes, or indeed more than three notes!
When we use the term "triad", we are being quite specific about the chord formed by using a root, third, and fifth built on a degree of a scale. The degree itself is the root. There are always three notes, and only three notes, and we only ever use the root, the third, and the fifth.
Any other combination, even if it has three notes, is not a triad, it is simply a "chord"!
We can give chords similar names to triads if they contain only the same notes of the corresponding triad. For example, a chord containing the notes C, E, and G (each of which could be repeated) is a "chord of C major" and is also a "chord of
I in the key of C major"
Here are some examples of chords that are not triads, and some chords that are also triads:
Some of the notes of a triad can be contained twice in a chord. We say that these notes are doubled, for example: "the third has been doubled" (if the third, E, is included twice or more in a chord of C major).
The dominant seventh is an example of a specific chord that is not a triad, and is constructed by taking the 5th degree of a scale, then adding a third, fifth and a seventh on top. While this is a very specific type of chord, it is not a triad, because it has four notes rather than three.
For this reason, the final chord (in G minor) in the example above is not a triad, even though it contains each note of
V7c only once.
Just like triads, chords can also appear in inversions. A chord with the root in the bass is in root position; if the third is in the bass, it's in first inversion; and if the fifth is in the bass, it's in second inversion.
Reducing chords to triads
Look at the following example, which shows several chords and their equivalent triads:
It is important to be able able to "reduce" chords to triads in the same way. The process should be quite simple:
- Starting from the bottom up, eliminate any duplicate notes - you should be left with just three notes. Do not remove the bottom note!
- Transpose the top two notes to the same octave as the bass note, but without going below the bass note.
- You should be left with a recognisable triad in one of the three inversions.
Example 5.2.3 shows the reduction of several chords to the underlying triad, as described above:
Reducing to a dominant seventh
Using the process above, you might find that you are left with four different notes rather than three. This could be because the extra note turns the triad into a dominant seventh chord, so watch out for this.
Here is an example:
Remember that a dominant seventh chord must be built on the dominant, i.e the 5th degree of the scale. A seventh chord that is not built on the 5th degree is not a dominant seventh! In the example above, the key is F major and the chord is indeed built on the 5th degree (C), and is therefore a dominant seventh chord.
Open and close
In step 1, above, when you eliminate duplicate notes, you are left with the notes of a triad but they will probably be widely spaced, rather than the tight group of three notes that look like a familiar triad.
When the notes of a triad are widely spaced, we call this a triad in open position. When the notes are transposed such that they are all within the same octave, we call this a triad in close position.
Triads in open position can equally be in inversions and can be treated just the same as triads in close position, but for ease of analysis and speed of recognition we prefer to write down triads in their close position.
As well as working out what a many-note chord is from a given passage of music, we also need to know how to write down many-note chords of our own. How we do this depends partly on the instruments and voices for which we are writing. One common situation in which you will need to write down chords is for an SATB choir.
SATB is short for soprano, alto, tenor, and bass. These are types of voice ranges in descending order of pitch, with soprano as the highest voice, and bass as the lowest.
Each of those voices needs to sing notes that are in its range, and we have to make sure that, ideally, we include each of the chord notes in order for the chord to be recognisable.
We look at the SATB line-up in more detail in Voices, but here are some key points:
- Keep the alto voice below the soprano voice
- Keep the bass voice below the tenor voice
- Don't go above or below the stave in the soprano voice
- Don't go below two ledger ledger lines in the alto voice (i.e., low G is the lowest comfortable note)
- Don't go above two ledger lines in the tenor voice
- Don't go below the stave in the bass voice
You can see from these rules that the tenor tends to mirror the alto in range ("two ledger lines"), and the bass tends to mirror the soprano ("not below/above the stave").
In general, if you keep within the stave for each voice, and do not cross the voices, you should be safe!
The example below shows a hymn-tune harmonisation for SATB voices:
Check through to make sure that each chord has all three notes present, and try reducing some of them to triad form.
If we are writing three-note chords in four-part music, then it is obvious that one of those notes must appear twice (i.e., one note must be doubled).
It is usually best to double the root of the triad - it is the most important note and deserves extra emphasis. If, for reasons of good part-writing, this is not possible, then it is acceptable to double the fifth. It is seldom a good idea, however, to double the third, so you should avoid doing this.
It is good to practice writing chords in four parts. Start by just scoring individual chords, and then try harmonising a simple tune, in which each note has one chord. We will look further at how best to do this in Writing harmony.