Why Two Notes Played Together Aren't a Chord

Yes.  The old two-note conundrum.  

What is a Chord?

Very often you'll read the following definition of a chord:

'A chord is two or more notes played simultaneously'.  

But this is an incorrect definition.


Why is it incorrect?  Because two notes played simultaneously isn't a chord.  

Of course, it also isn't just a note - as we have two of them.  

The important question is:

Why aren't two notes played together classed as a chord?

We'll get to that - but first let's define what a chord is:

A chord is more than two notes sounded simultaneously.  

I generally use the word 'sounded' rather than 'played', as played can be read to imply a musician physically playing something - whereas 'sounded' is more open, in terms of meaning.  However, either will suffice.

Very, very important point: chords don't have to sound 'good' in order to qualify as chords.  'Chord' is a definition of quantity - not a subjective experience of pleasure.  

When a 5-year old smashes hands/arms/elbows down on the piano - yes, the little one is playing chords!  Possibly not very pleasant chords, but still - chords they are!  

There's a Classical piano piece where the pianist pushes down every piano key by sitting a plank of wood on the whites, and another plank on the blacks.  Is the sound cacophonous?  Possibly.  Is a chord being played?  Yes.  No mention of composer here: do a little digging and see if you can find the piece for yourself.  

If anything, thinking along the above lines should be quite freeing.  Music doesn't have to sound 'good'.  There's a time and a place for everything.  Pleasant music isn't very appropriate during a tense horror scene.    

So - chords don't have to sound 'good' to be chords (and music doesn't have to sound 'good' to be music).  

But chords do have to consist of more than two notes.   

What is an Interval?

In music, interval is an important concept.

The term has nothing to do with everyday use i.e time/duration.

Interval = the distance between two notes.  

We have specific musical terms for certain distances.  It can get rather confusing, as the names for intervals change.

We get semitones/tones/thirds/fourths/fifths etc.


When we have two notes, we have the presence of an interval.

You could think of each note as a house, and the interval as an automatically-created path between the houses.  If we remove one of our two notes and return to only one note, the path disappears.



We'll take our twelve musical notes, and plot them in a circular format:

 


Let us take two notes (we'll take C and E) and plot them on the circle.  We'll also add the 'path' i.e. interval between the notes:

   
As you can see, two notes creates one interval i.e. one 'path':

Psychoacoustically, a chord is the presence/perception of more than one interval.

One note = no intervals.
Two  notes = one interval.

Hence we need more than two notes to have a chord.  We need more than two notes to create more than one interval.


Let's add a note to our previous diagrams.  We'll add G.  The notes we now have are C, E, and G.

Before looking at more diagrams, consider how many intervals you'll now hear:

You'll hear C-E
You'll hear C-G
You'll also hear E-G.

Your ear/mind hears all combinations of the sounds.

Let's add G

As well as hearing C-E, your ear now also hears C-G...

...and it also hears E-G

Three notes = three intervals.  Hence we have a chord i.e. the presence/perception of more than one interval.

It is impossible to perceive exactly two intervals.  We either have one, or three/more than three.


Mathematically, it also isn't a case of simply adding an extra interval for each extra note (for example: a four-note chord has six intervals, not four; a five-note chord has ten intervals etc).  If interested RE the why, on my YT page you'll find a video on the subject of Graph Theory.  Quite a long video, but it explains the mathematical relationship RE the number of notes and the resulting intervallic density of the chord.

The underlying maths isn't too important just now.  What is important is understanding the concept of why we need more than two notes to have a chord.


Remember: any amount of notes greater than two sounded simultaneously is, by definition, a chord, as any more than two notes creates more than one interval.


Three notes sounded simultaneously is a chord.
Forty-two notes sounded simultaneously is a chord.
587 notes sounded simultaneously is a chord.

Note = single, fixed pitch

Interval = *two notes/distance between two notes

Chord = more than two notes.

*Two common words for an interval are dyad, or - if you are familiar with blues - double-stop.  Both mean 'two notes sounded simultaneously'.



As we can see, an interval is an entirely unique category - not an afterthought.



I'm going above and beyond with the following, but here's an interesting way of thinking RE the above definitions:

Note = psychoacoustic perception of a single point within Euclidean Space

Interval = psychoacoustic perception of a line within Euclidean Space

Chord = psychoacoustic perception of shape within Euclidean Space.

Best

Kris