(
Musical) - A triad is three
notes that comprise a
chord. The notes are separated by a third. Thus, it is the first, third and fifth notes of the respective scale. There are four types of triad:
major,
minor,
diminished and
augmented.
The major triad consists of the first, third and fifth notes of a major scale, for example in C, these would be C, E and G. Thus C, E, G is a C major triad. The interval from C to E is a major third (two tones), and from E to G a minor third (one and a half tones). Similarly, an E major triad is E, G#, B.
A minor triad consists of the first, third and fifth notes of the minor scale. An A minor triad, for example, is A, C, E. The interval between A and C is a minor third, and between C and E - a major third.
The dimished triad is similar to the minor triad, but with the fifth lowered a half tone. So the intervals are now a minor third between the first and third and a minor third between the third and fifth. For example, an A diminished triad is A, C, Eb.
An augmented triad is like a major triad, but with the fifth raised a semitone (half a tone). Thus between the third and fifth we now have a major third. For example, C, E, G# constitutes an augmented triad.
Although I said there are four types of triad, there is also a fifth. A sus4 triad. Not all musicians consider this to be a triad, as it's not thirds one on top of another, but some will consider it, as it is a basic chord comprised of three notes that is not one of the other four. So you can choose whether you wish there to be 4 or 5 triads. Whatever makes you happy. In any case, a sus4 triad is a fourth followed by a major second. If you wish, it is a major or minor triad with the fourth instead of the third. So a Csus4 triad is C, F, G.
Some people consider a sus2 to be a triad too, but it isn't really. It's just an inversion of sus4. So Fsus2 is F, G, C, which as you can see is the same notes as Csus4 (so you could write it Csus4/F).
Summary:
Triad | Intervals | Example
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| |
Major | major third, minor third | C E G
| |
Minor | minor third, major third | C Eb G
| |
Diminished | minor third, minor third | C Eb Gb
| |
Augmented | major third, major third | C E G#
| |
Sus4 | perfect fourth, major second | C F G
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