Constructing Major, Minor, Augmented and Diminished Triads
If you want to know how to build interesting sounding chords you'll first need to understand how to construct triads. Triads are in fact chords and familiarizing yourself them will make writing chord progressions and extended chord voicings easier later on.
What's a Triad?
A triad is a chord constructed with 3 notes. When in root position (the root note is on the bottom) each note is a third away from the last (if intervals are new to you check out the intervals tutorial). Triads are a basic chord structure and the basis of how other types of chords are constructed. There are four types of triads:
Hopefully you've read about major scales already; if not go check them out, triads will make much more sense. To create a major triad simply stack the 1st, 3rd, and 5th notes of a major scale on top of each other.
Let's take the G major scale: G - A - B - C - D - E - F#
Take the 1st, 3rd, and 5th scale degrees out: G - A - B - C - D - E - F#
The G major triad would be G - B - D.
Minor triads are constructed in the same fashion as major triads, only based off the minor scale. Take the 1st, 3rd, and 5th notes of the scale and you end up with the minor triad.
Augmented triads have a cool sound, very mysterious. An augmented triad is a major third on top of another major third. So basically, you can take a major triad and raise the 5th note by a half step to get the augmented version (since a major triad is a major third on the bottom and a minor third on the top). The augmented triad has lots of uses and can resolve in many ways. By ‘resolve', I mean it naturally has the tendency to lead into another chord. We'll get into that later. Just familiarize yourself with how the augmented triad is constructed in comparison to the major and minor triads.
A diminished triad has a dissonant sound to it. It's built using two minor thirds.