Power Chords

Why the fifth and nothing else

A perfect fifth is the simplest relationship after the octave. Two such notes blend almost without beating, and they stay clean no matter how hard the signal is driven.

A third does not. Distortion generates difference tones — frequencies that were not in the signal — and for a fifth they reinforce what is already there. For a full triad they scatter, and the chord turns to mud on any amplifier.

The three forms

Two-note C5 is x35xxx: root on the fifth string, fifth on the fourth. Add the octave above and you get x355xx, which sounds noticeably bigger while carrying no extra information — that is the whole point of it.

The third form inverts the interval: root and fourth instead of root and fifth, x33xxx. It sounds thinner and more strained, and players reach for it precisely for that difference.

Why it is played so fast

One finger, or two, covering two strings at the same fret. The hand can jump between chords faster than it ever could with barres, and that speed is what made riff-based guitar playing possible in the first place.

The shape never changes either. Move it and you have a new chord, with no knowledge of key signatures required — which is why it is usually the first thing a beginner learns after single notes.

The mode is decided elsewhere

Since there is no third, C5 does not commit to major or minor. The vocal, the bass or the surrounding chords decide, and the guitar part stays neutral underneath.

There is a practical benefit: one riff can serve both a major and a minor version of a song. Change the melody and the guitar part does not have to move at all.

Not only for distortion

Clean fifths are an old sound, much older than the amplifier. A bagpipe drone, a hurdy-gurdy and most folk instruments with a sustaining note hold exactly this interval, and the ear treats it as natural background for a melody.

Stacked fifths do the same job in orchestral writing — open, wide, without naming a mode. The quartal group in this catalogue covers that use in more detail.

On piano and bass

Pianists reach for the same two notes when the left hand needs weight without mud. Low on the keyboard a full triad turns muddy for acoustic reasons rather than electronic ones — the intervals between the harmonics of two low notes fall inside the ear's critical band — and a bare fifth stays clear where a third does not.

For bass players it is less a chord than a decision about the octave: root and fifth, or root and fifth and octave, played as a double stop. Same two notes, and the same reason for choosing them.

Frequently asked questions