Dissonance

"An unstable tone combination is a dissonance; its tension demands an onward motion to a stable chord. Thus dissonant chords are 'active'; traditionally they have been considered harsh and have expressed pain, grief, and conflict."

—Roger Kamien (2008),

            Dissonance is the musical term for any form of unstable and usually unpleasant sounding intervals, chords, or sounds occurring within music. Dissonance creates tension and stress (usually) to be relieved though resolution.

            Dissonance is perceived in two ways, one is measurable and rooted in our physiology; the second is a product of musical training. The one of the structures of the inner ear that allows us to hear as we do is the cochlea. Within the cochlea are numerous specialized hair-like structures organized in groups that respond best to specific frequencies. The grating and jarring dissonance that arises from very close intervals such as a minor second result from the two frequencies overlapping the areas of the cochlea they stimulate. This creates an unpleasant sound due to the tangled singles the brain is receiving due to this overlap.

            The second form of dissonance is cultured, trained within each of us. As we listen to the music of our cultures, our brain organizes certain rules. These rules are expected to be followed, and when they are broken, or when what we have anticipated does not happen, we experience discomfort. Imagine watching a basketball game. All is going as normal when suddenly a player pulls the ball to his chest and sprints across the court without dribbling. People create an uproar over the foul they have just seen. The rules they have been conditioned to follow, and have come to expect others to observe as well, have just been broken. If a man who had never seen or heard of this sport were to see the same thing, he would likely think nothing less of the traveling player, if anything he would find him clever for trying a new solution to the problem of getting the ball across the court. This is the same thing we experience when we hear an unresolved chord, a suspension gone awry, when a player steps out of the set key, disrupting the harmony. They are products of culture, of our cultivated expectations for music. Most people do not know the rules; however they have listened to enough music to know when something is not right, just as an armature spectator may not know the terms for each foul, or know the hand signals used by the referee; however they can still know when someone has broken the rules.

            Dissonance can be used to convey negative emotion, tension, anger, discomfort, whatever the composer may need. It is often used as a spice to a specific musical moment; however some genres use dissonance as their defining aspects. Some heavy metal and hardcore groups us dissonance to add to the ambient sense of anger, toughness, or evilness of some music. In any case, dissonance is manipulated to strengthen the emotional contours of music and draw the audience in to the music.