What is dissonance?

A question on harmony, or perhaps the antithesis of harmony:

What do people mean by “dissonance” and other such terms when talking about chord changes?

Dissonance, according to the dictionary, is “an inharmonious combination of sounds; discord; any lack of harmony or agreement.”

When we listen to music, certain notes sound pleasing when played together. For many people, the interval of a major third (C and E, for instance, or G and B, etc.) is perhaps the most pleasant, or harmonious sound.

Dissonance is when we create a sound that is not harmonious. There are degrees to how harsh the dissonance can be. If you were to play a C (5th fret, G string) and a C# (2nd fret, B string) together, it would sound as if the notes are clashing.

In a sense, they are – you feel that this combination of notes wants to turn into something else. It’s almost as if you’ve caught them in mid-metamorphosis. Play these notes again and now slide your finger on the C down to B (4th fret, G string) and at the same time slide the C# up to D (3rd fret, B string). Can you hear how the dissonance completely disappears? It’s the interplay between dissonance and harmony that helps to add a dramatic, almost dynamic aspect to a song.

Dissonance can be created in countless ways. You can add a dissonant note to a chord (even via a melody or bass line), you can play one chord on top of another, or you can play a string of chords while holding one note steady in the bass.

But the thing to remember is that not everyone hears the same sorts of dissonance. It’s a matter of what you’re used to. That C/C# thing we mentioned earlier? A jazz player would write it off as a C#maj7 and might not think of it as dissonant at all.

If you’ve got any questions, we at Guitar Noise are always happy to answer them. Just send any of your questions to David at [email protected]. He (or another Guitar Noise contributor) may not answer immediately but he will definitely answer!