Audio: consonance (0:04)
consonance plays a consonant sound followed by a dissonant sound on two violins. The score in the consonance figure shows that both sounds are intervals, two notes played simultaneously. The first interval is a major third and the second interval is a tritone.
Consonance and dissonance are opposites of each other. A consonant sound is perceived as pleasing to a listener, a dissonant sound is perceived as unpleasant. The terms, pleasing and displeasing, are loaded, and more neutral words are sometimes used instead such as stable and unstable.
The first sound in consonance is an interval of a major third. This sound is the archetype of consonance. It is the bedrock sound of harmony in Western music and a sound that is in wide use throughout the world.
The second sound in consonance is the interval of a tritone. This sound is the archetype of dissonance. It was banned by the church in days of yore and is forbidden in some types of music such as counterpoint. It is sometimes shunned by vocalists because it is perceived as difficult to sing.
Consonance and dissonance permeate music at all levels. At the level of an individual listener, there is clearly going to be a difference in the perception of consonance from one person to the next. It is also true that different cultures and groups in society have differing views of what is consonant and what is not. To complicate matters even further, what individuals and society view as consonant and dissonant changes over time.
Consonance is a fascinating subject and it will crop up regularly when you write music. Differing ideas about consonance and dissonance will lead you to write different kinds of music. Ultimately, you are the best and only judge of consonance and whether to incorporate dissonance into your music.