Chords are a key topic in music theory. Each and every song is built on top of them and this gives them their mood (e. g. happy, sad). But before reading this article I would strongly recommend to read the article about intervals because this will improve your understanding of chords and make this session easier overall.
In music theory chords are a group of at least three notes that are played simultaniously. In this article I cover the most important forms of chords called major, minor, augmented and diminished.
Before explaining these four chord types there is some knowledge you need to gain. In general, chords are named after their root note, e. g. a C Major chord is called like this because it's root note is a C. In most cases the root note is the lowest note you see so determining it isn't really hard. But in some cases the chord might not be in root position. Have a look at this example:
A chord inversion is a chord which notes have been shifted. Now, the root note no longer is the lowest note. Inversions are built by taking the root note and shifting it up an octave. This is called the first inversion. The second inversion is created by shifting the third up an octave so in this example the note order is G, E and C.
Major chords consist of the 1st, the 3rd and the 5th note from the corresponding major scale. This makes them consist of a major third between the root note and the third and a minor third between the third and the fifth. Major chords give a happy and content sound.
Minor chords consist of the 1st, the 3rd and the 5th note from the corresponding minor scale. This makes them consist of a minor third between the root note and third and then a major third between third and fifth. Minor chords sound kind of sad and sometimes give a melancholy feeling.
In a major chord there is a major third followed by a minor third. Augmented chords consist of two major thirds which gives them a tensioned and instable feeling.
Diminished chords consist of two minor thirds so B Diminished consisting of B, D and F is a perfect example. Like augmented chords diminished chords create a kind of tension which can be resolved by playing the root chord from the corresponding scale. B Diminished is part of the C Major scale so this is the chord to resolve this tension.
In conclusion, chords are an important topic in music theory used to create interesting chord progressions. Major and minor chords are the most commonly used but augmented and diminished chords create tension and make a song interesting. Make sure you master every chord by using the chord quiz.