So maybe you think "Chord Theory" is a waste of time? Well let me tell you, chord theory is worth your time! Have you ever noticed when you're trying to figure out a certain chord in a particular song that all of a sudden you arrive at the right chord, but for some reason it just doesn't sound exactly like the one being played? Something about it just seems to sound different. Well it's a good chance that the reason for this is because a different "voicing" is being used. The term voicing is just anoter way to describe all the different fingerings and places that chord can be played on the fretboard.
So as you become familiar with the different chord voicings that are used by today's rock guitarists it will become a lot easier to figure out songs and also your composition skills will greatly improve when you have some chord theory skills under your belt.
Before we get to those "rock chords", let's get into some basic chord theory. For starters, those of you who are not sure of the difference between sharps and flats, let's clear that up right now. A sharp (#) raises a note's pitch one half step. A half step is equal to one fret on the guitar. The note A# is one fret higher than an A note on the guitar. A flat lowers (b) lowers a note by a half step. The note Ab is one fret lower than the A note on the guitar. A note is natural when it is neither sharp or flat.
All natural notes are separated by a sharp note and a flat note, execpt for B and C, and E and F. A# and Bb are actually the same note with two different names. The same is true for C# and Db, D# and Eb. The key is what determines whether a note is considered sharp or flat. Since most rock and metal progressions mostly center around major and minor chords, most of this lesson is based on those chord types.
So what is a major chord? The first thing you need to know about any chord is that it is constructed from the major scale of the same letter name. Any type of C chord, whether it is C major, C minor, C7 etc., will be constructed from the C major scale.
The next thing to realize is that every chord has it's own formula. The formula for a major chord is 1, 3, 5. This means that the major chord consists of the first degree (or root), third degree, and fifth degree of it's major scale. Below is a C major scale. All the scale degrees have been numbered.
By using the major chord formula with the C major scale, we get the notes C, E, G. This type of three note chord is called a triad, a major triad. There are four types of triads: Major, Minor, Augmented, Diminished. The notes in this triad can be arranged in any order: C, E, G - E, G, C - G, C, E - etc. Remember that term voicing? Well it refers to the actual order of the notes.
When writing or refering to chord voicings, the notes are named in order from lowest to highest in pitch. If a chord is "voiced" with it's root note as the bass note (lowest pitch note), this would be what is considered root position. If the chord's third degree is the bass note, then it would be what is called a first inversion. If the fifth degree is in the bass, then we call it a second inversion.
Any of the notes in a given triad may be repeated. If there are more than three notes present (ex: C, E, G, C), then we call it a chord instead of a triad. In this case however, the example I just gave you would still be considered a triad because it contains the first, third, and fifth degrees only. So you are probably starting to see that there are a lot of options you have when it comes to variations, or voicings for the same chord.
The formula for a minor chord is 1, b3, 5. The only difference between a major chord and a minor chord is the third. The major chord contains a natural (unaltered) third of it's major scale, and a minor chord contains a flatted (lowered) third. By using the minor chord formula with the C major scale, we get the notes C, Eb, G. This is a C minor triad.
Although major and minor chords contain the root, third (or flatted third), and fifth degrees, it is very common in Rock and Metal for these chords to be played using the root and fifth only. This is what is known as a "Power Chord". This chord gives you a very strong and powerful sound, hence the name power chord.
The power chord is neither major or minor because it contains no third. So when put into a progression it can function as either a major or minor chord. This is why the power chord is so popular.
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