[THEORY] Triads

Andrei Moraru

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Hello one and all and welcome to our newest installment in the music theory series. Today we discuss triads.
In music, a triad is a group of 3 notes, played at the same time. Of particular interest to us though are the triads formed by having 3 notes, each separated from the previous one by a third. More often than not, when referring to triads, musicians think of the following four types:

major triad – a triad consisting of a major and minor thirds
minor triad – a triad consisting of a minor and major thirds
augmented triad – a triad consisting of two major thirds
diminished triad – a triad consisting of two minor thirds

Musicians will also use the term chord to describe a triad, especially when playing the piano. This is caused by the fact that in order to play a chord on an instrument, you require at least 3 notes. A triad fits the bill for that.
The easiest way to construct a major triad is to stack the 1st, 3rd and 5th notes of a major scale on top of each other. In the case of your beloved C major scale, the major triad for that is C-E-G. As you can see, we have a major third between C and E and a minor third between E and G.
In order to obtain the other triad variants, all we have to do is apply some accidentals. For example, if we flatten the E note, we get C-E flat-G, which is a C minor triad.
Now, if we sharpen the G note, we get C-E-G#, which is a C augmented triad. And finally, if we flatten both E and G, we get C-E flat-G flat, which is a C diminished triad.
Why are triads important you ask? Well, because on any instrument, they are the basis for playing chords, be it major/minor/augmented/diminished or more advanced ones like seventh, 9th etc.
That about covers it for this post.
Previous posts:
Notes, pitches, semitones and octaves
Accidentals and enharmonic-notes
Musical Intervals
 

Dominik Gräber The Great

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Hey, thanks for sharing your knowledge!
One question though, you said “…in order to play a chord on an instrument, you require at least 3 notes.” But I thought we can play a power chord out of two notes to which we still refer as a chord or am I missing something?
 

Andrei Moraru

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Huh…interesting point you’ve made there. And technically correct, you can play a power chord by using only two notes.
I cannot edit my first post, so I’ll just say it here: the rules above (3 notes per chord) apply to the major/minor/augmented and diminished chords only, with regards to this post anyway.
I’m so used to playing power chords by using all 3 notes that I forgot about that little variation that you have mentioned, though it’s very guitar specific.
 

Jak Angelescu

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Dominik and Andrei,
You both are correct. A powerchord is technically called a chord even though it only has two notes. HOWEVER, it cannot have a proper name because it’s only two notes. That’s where the confusion comes in. Powerchords are VERY ambiguous. Let’s take the chord of A minor for example and I’ll show you what I mean.
If you play an A minor power chord in the open position, you only play A (open) and E (D string 2nd fret). HOWEVER, an A Major chord ALSO has this. It consists of A and E as well. So if you were to play an A minor power chord (or even an A major powerchord) there’s no distinguishable 3rd note to say “Yes, this IS an A MINOR chord” or “This is an A MAJOR chord.” That third note is truly what gives a chord it’s name.
So to make Andrei’s point valid, we should conclude that you CAN have only two notes to make a chord, however, because of ambiguity and for clarification purposes to actually give the chord a name and a tone/harmony value, we need that third note.
Example:
Am notes are: A-C-E
Amaj notes are: A-C#-E
As you can see, BOTH chords have A and E in them. It’s that C or C# that really differentiates between a minor chord and a major chord. So technically speaking, yes, a chord DOES need to have three notes in order to have a clear tone value. But you can have only two notes to make a chord, but chord will be ambiguous with no actual set tone value. I hope this makes sense! 🙂
 

Andrei Moraru

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Jak put it best 🙂 .
In the words of Terry Jeffords from the 99 though: “Power Chords are dumb”. The idea is that when you’re playing a power chords you’re basically playing a fifth on which you can add the octave of the root note. Thus, as Jak said, said power chord doesn’t really have a quality associated to it (major, minor, augmented or diminished).