A triad is a chord made up of three notes. These chords form the basis for all other chords. A lot of music contains ONLY triads, so they're very common!
Before going further, make sure you understand what a major scale is! You can refer to this lesson.
Remember that a major scale is made up of seven notes with the following number of frets between them:
2 - 2 - 1 - 2 - 2 - 2 - 1
We'll be using the key of C major for examples here since it has no sharps or flats. The notes are C - D - E - F - G - A - B - C.
Triads are built by skipping notes in the major scale until we have three. Why do we skip notes? That's just how triads are made - I don't have the answer, but I do know that when you don't skip notes the chord you get sounds pretty bad. Try playing C D E as a chord and you'll see what I mean.
So to get a proper triad, we're going to use C E G, the first, third, and fifth notes of our scale. Try playing it this way. The chord shape is exactly the same notes but played on adjacent strings so you can hear how they sound together.
Those three notes, when played together, make a C major chord. When you play the standard C major (the chord you learn as a guitar nooblet) you play five separate notes, but each one is either C, E, or G.
You always name the chord by the first note, in this case C. Another name for this note is the "root" of the chord.
Notice that there are four frets between C and E, and three between E and G. A major scale can be played from any note (as long as you follow the pattern above). Just like a scale, a major chord can be played from any note - as long as you follow this pattern. So the pattern for a major chord is:
4 - 3
Just like the pattern for a major scale, this pattern is set in stone. Any time you play this combination of notes together, you get a major chord!
To make things easier later on, remember that we are playing the first, third, and fifth notes of a major scale to make the major chord. Sometimes we call the notes in a chord 1, 3, and 5 for easy reference. So a musician might say something like, "I'm playing C major, you take the third." That means you play E.
That's our first triad type - the major chord. There's only three others!
It turns out there are more triads hidden in the key of C major. We already used C E G, but what about starting on a different note? If you start on D and make a triad by skipping notes, you get D F A.
The number of frets between D and F is three, and between F and A there are four. So our pattern for this chord is:
3 - 4
This is NOT the same pattern as a major chord! If you play these notes together, you will hear that it doesn't sound like a major chord either. This triad is a minor chord, and the pattern we just discovered is the pattern for a minor chord starting from anywhere. Here's D F A in tab:
We can name this chord D minor because D is our root note. It's kind of neat that there's a D minor chord hidden in the key of C major. We'll go into more detail on that in another lesson.
Major and minor chords make up the vast majority of popular music in most styles. There are two other types of triads that can sound weird and have limited uses. Nevertheless, they do show up now and then, so I'll briefly mention them. Sometimes you *want* to sound weird, right?
Diminished triads have the pattern 3 - 3. Augmented triads are 4 - 4. Try them out! Here's some sample tabs for diminished and then augmented:
Here's a clip of each triad type.
Four Triad Types
Each type has an associated emotion or feeling that goes along with it. As with the major scale, I can't really explain the *why* of this, but it probably has something to do with the fact that this is how chords are commonly used. So the feelings tied in with these chords are sort of set in stone in our minds. This doesn't mean you can't experiment though!
Of course, songs generally combine chords together, and so it's hard to identify a collection of chords as mainly one of these. But in general a chord progression with a lot of minor chords will sound more moody and sad than a progression full of major chords. Sometimes the chord you start or end a song with makes a big difference too. The above list also helps you in identifying the sounds of triads.
Start identifying the kinds of triads used in music you listen to. About 90% of the time, you're going to be hearing regular major or minor chords.