This post is one of a growing series of holistic investigations into various aspects of music theory. The full list can be found in the Posts page under the category Music Theory De-Mystified.
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This is a key tenet in my approach to music theory. However, if you disagree, feel free to comment.
Most music has both a melody and chords. Even a melody by itself is usually built on chords, it’s just that we don’t hear them. We call this an implied chord progression (when no chords are written, we can deduce the likelihood of potential chords by the evidence provided in the melody such as phrase structure, the actual notes used and the use of accidentals).
A chord represents a key- at least basic major and minor chords and their common variants do. How effective they are at establishing their key depends on low long they’ve got. Yes, time. The longer the time spent on a chord, the more it feels like THE key.
A melody is a journey. Typically it starts at home (in the home key) then travels to one or more visiting keys, represented by the main chords along the way, eventually arriving home again.
Just like a physical journey, the trip can be long or short, fast or slow, bumpy or smooth, visiting nearby or exotic places on the way. Everything that applies to a physical journey has its parallel in a musical journey.
There are three parts to any trip- the departure (including any prep such as packing), the travel and the arrival. Similarly, pieces (and the phrases within them) have a start, a middle and an end.
Time, Space and Culture Shock
A journey can be brief or extensive, or anything in between. The places you see can be familiar or exotic, near or far.
- A trip to the local shop to get staples might be a 5-minute walk around the corner or up the street. You spend just long enough to do a common task in familiar surroundings and head back. This is the most basic journey; familiar and short.
- You might drive across town to visit a close friend or family. Again, you are in familiar surroundings, yet you travelled beyond your immediate neighbourhood. This still feels like a small and safe journey yet you may spend hours on your visit and be surprised by the changed traffic or weather conditions coming home. A tiny bit more complex journey than the first example.
- Maybe you’ve chosen to visit someone out of town or in another state. You might be invited to stay a few days. Longer distance means a little less familiarity: you don’t know the roads so well, where the post office is, the bed feels a bit different, etc. After a day or two, you start to get used to this. The longer you’re there, the more it feels like home.
- While you’re there, you might take mini trips within the journey- go to the shop, the beach, maybe even camping out.
- If you stay away long enough, when you come home it feels a bit strange at first. You almost turn the door key the wrong way, the colour of the wallpaper isn’t quite as you remembered it, you didn’t realise you were low on a few staples.
- What if you set out on a grand adventure to visit strange and distant cultures? The journey is either massive, with strange and mysterious stops on the way, like an ocean journey, or super fast, almost like a blur, as in a flight. When you arrive, it’s almost alien. Everything’s different: the living conditions, the language, the food… Stay there for a while, however, and you gradually pick up a few basic words, learn a bit about the local neighbourhood and start to feel more settled.
- Were you to stay in an exotic culture for long enough, it would start to feel like home, and your memories of your real home become less and less clear. Coming home after living there for years, home itself would feel like a very strange place at first. Stay somewhere long enough and you might even come home with a foreign accent!
All this can be mirrored in the way a piece of music progresses. The melody is the traveller, the main chords are the visiting points. Time is time.
The relationship between each chord and the home key (as well as between one chord and the next) is the relationship between home and the various places visited on our travels. As a (basic) chord represents a key, the main chords mark out the visiting keys in the journey.
Closely related chords
Chord relationships are key relationships. A topic in itself, this is worthy of revisiting in at least one separate post. However, in general, keys (and chords) are related by how many notes they have in common. There are basically three types of key relationships:
The Cycle (or Circle) of 5ths
The cycle of 5ths is a sequence of all major and minor keys in increasing and decreasing key signature order, usually represented as a circle. Octaves are unspecified, as it’s just a list of keys. Adjacent keys in the cycle of 5ths have only one note different in their scales and both chords are made up of notes in the home key.
See my Beginner’s Tip for a graphic of the cycle of fifths, including relative majors/minors.
Adjacent keys in the cycle of 5ths are the closest companions. Many pieces only use 3 chords: that of the home key, previous key and the next key in the cycle, otherwise known as the Tonic, Subdominant and Dominant or I, IV and V. As we progress away from our neighbours, the keys sound less closely related and the chords a little more independent. Distant key relationships produce a startling or disorienting sensation in the listener.
Relative major and minor
All the common tonalities used in Western music have either a major 3rd or a minor 3rd from the root note. In this way, modes can be categorised as “like major” or “like minor” and be represented by a major or minor chord accordingly. It’s reasonable to talk in terms of major and minor chords, even if the piece is in another mode.
For every major scale, there is a minor scale with the same key signature (and vice versa). When the music changes between relative major and minor, the root note and tonality change but the notes all belong to the home key. As a chord progression, going from relative major to relative minor (and vice versa) feels more like taking a small step back rather than a significant change in key. Relative major/minor chords are often interchangeable in an accompaniment, depending on whether a more direct or a slightly indirect and more sophisticated effect is desired.
Major and minor on the same root note (parallel major and minor)
A major and a minor scale on the same root note have 3 notes that differ between them, so they only have 4 notes in common. In the cycle of 5ths that amounts to keys which are 3 steps apart, a relatively indirect relationship, yet they sound like they’re much more closely related. As it happens, only one of the three chord notes is different-the 3rd. The root note and 5th are both the same. The only thing that seems to change is the mood, the tonality.
Back to the present…
In short, closely related chords feel comfortable, almost predictable, as the melody arrives there – the friendly key next door…
Of course this is mitigated by the directness of the trip. We could potentially weave through a myriad of other keys before arriving next door, blindfolded and bedazzled, and it might then take us a while to realise where we are, but by and large, closely related keys can be freely visited in comfort.
More adventurous journeys use less direct key relationships or follow a cascading progression of keys in the cycle of 5ths to arrive in a new land.
When listening to a piece, try to feel not just the more rapid flow of the melody, but the deeper, underlying flow of the progression of keys through which the melody travels.
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