Dissonance vs. Consonance: Essential Elements of Music

         Today we're going to talk about consonance and dissonance, how they are created in music and how they interact with each other.  
       
          We all know what a "utopian" society is right? It's a civilization that is the very essence of perfection. Everything is idealistic to the creators. There are no wars, no starvations, and no movements against the system, and this is what creates a seemingly perfect society. On the other hand however, there is chaos, "anarchy" as some might label it, and in this confusion no social structure or civilization can be made out from the clashing of people and their conflicting ideals.
           So we know what it means to live in a utopian society and a chaotic society, now let's connect this to music theory in the form of harmony. Harmony is the use of simultaneous pitches/tones/voices/chords in a phrase or piece of music. When listeners think of harmony, they'll think of interacting intervals being voiced by different instruments or vocals in an arrangement. Typically, people associate harmony as always sounding "good" or "etherial", when really harmony can sound heavenly or uneasy depending on what type of harmony you're going for.
 
    Let's put this into practice before we begin to break this down;

Here is an example of the song "Twinkle Twinkle Little Star" written in two-part harmony. Notice that the melody (the primary line) is written in the treble clef while the harmony (complimenting line) is written in the bass clef. The affect of this is to provide support for the melody from a lower octave, giving the song a stronger sound and increasing the range of the piece.

When talking about how notes or chords interact with each other, it's helpful to think of two types of relationships; Dissonance and Consonance.

Consonance is a harmony in which (while sometimes spread out) form triads, chords, and intervals that are considered "stable" or at a resolved state. Dissonance is quite the opposite however, and is defined as an arrangement of notes or intervals that are "unstable", or unresolved. Occurrences of dissonance in music usually are compared to "harsh" sounds, or ones that make the listen expect a resolution. Different kinds of consonance can be further divided into subgroups such as "perfect" or "imperfect" harmonies, but the general idea is that these sounds "blend" well together and give off the illusion of fusion between two tones.

"A stable tone combination is a consonance; consonances are points of arrival, rest, and resolution."
-Roger Kamien

For example; The chords to the left are paired together in this manner because the second is resolving the first. Notice that in the Dsus4 chord, a major second is formed between G and A. Because of the quality of this chord, it is an unresolved version of a D major chord, and the use of the D major chord after it is what resolves the phrase. Similarly, the G7 chord is at a state of unrest and wants to resolve to the tonic chord of the progression (which is C major). Unresolved cluster's of seconds can also create dissonance because the pitches are clashing with one another and want to resolve into a more pleasant m3 or a triad.

But just as conflict is important in the plot line of a good story, so is dissonance in the harmonies of a good arrangement. Without this "clashing" or need to resolve there would be no feeling of movement throughout the piece, and as pretty as it might sound it would be uneventful and...boring. So be thankful of these points of musical interest! They are the embed flow of motion in music!

Here' a video I found that helps to explain this concept in a little more detail by providing excellent examples of what each form of harmony sounds like; Consonant and Dissonant Harmony

If you have any more questions about dissonance or consonance, feel free to leave comments below!

Sincerely, ZS