The word dissonance comes down to us from the Late Middle English period (1300 to 1500). It means “to disagree in sound.” That, in turn, comes from the original Latin verb dissonare.
Dissonance is most associated with music because it describes notes that “disagree” with one another to create a harsh, abrupt, or even jarring change in the flow of the music.
The opposite of dissonance is called consonance. The notes stream smoothly together, sound harmonious, and evoke a pleasant and stable sound. Consonant compositions are easy to listen to for long periods without the need for a chord change. (More on chords in a bit).
Because we think of music as something that should be pleasant, flowing, and consonant, it’s fascinating that some of the greatest musical minds of all time have eagerly adopted dissonance to “change-up” music to make it more interesting and innovative.
Some forms of music, such as jazz, make extensive use of dissonance. But many classical compositions and even modern rock music make frequent use of this technique as well.
Before we go further into our discussion of dissonance, why not take a break right now and listen to several examples of compositions by great musical masters that demonstrate dissonance. We’ll also offer a more recent, popular music selection that shows how dissonance sounds.
First, give a careful listen to Wolfgang Amadeus Mozart’s String Quartet No. 19 composed in 1782:
Now, by way of contrast, listen to the lovely, harmonious, and consonant Mozart piece, Sinfonia Concertante. Warning: The following music may produce feelings of rapturous delight:
In the first example, Mozart made liberal use of dissonance. In the second composition, you may have noticed the distinct difference of a flowing, consonant composition.
Next, listen to “Roundabout” by Yes, the English progressive rock band. Pay close attention to the section starting at 1.45 through about 2.15. In that interval, you will hear an abrupt yet enormously pleasant insertion of discordant guitar riffs that break in to play a dissonant set of chords that delight the listener.
This section is an example of what is called “metric dissonance” because there is a measure-preserving direct grouping of dissonance between the drums and the guitars. Note that some argue this is an example of “rhythmic dissonance” and not so much “metric conflict.”
Some would further argue that this portion of Roundabout is actually the insertion of a “counter melody,” but the latter is defined as a melody to be played simultaneously with a more prominent lead melody. The key here is that both melodies must be in key to be a counter melody.
Whatever the case, just give it a listen. You’ll get the idea and hear an unmistakable example of dissonance.
Now for a more radical example of dissonance, take a listen to Rite of Spring, a 1913 composition by Igor Stravinsky.
When this piece was presented for the first time in Paris, the orchestra was not allowed to finish because the audience broke out in a riot! That’s how powerful dissonance can be in a piece of music. You may get a hint of why this is so even during the first two minutes as the dissonant elements provide haunting, disturbing effects.
Right and Wrong Dissonance
To be clear, when we’re talking about dissonance in music, we’re referring to compositions that purposefully incorporate non-harmonic intervals for artistic effect. That’s the good, planned kind of dissonance. The bad kind is simply when a musician makes a mistake, strikes a wrong key, or is playing an instrument that is out of tune.
Interval and Chords
When discussing both consonance and dissonance, what’s being referred to are intervals and chords. So let’s look at them both.
The interval between two notes refers to how much higher or lower one note is than the other. The interval is determined by the number of half-steps that exist between them.
Intervals are referred to by several different names by musicians, such as “major third” (four half-steps), “perfect fifth” (seven half-steps), or “octave.” An octave half-step is an interval that has a higher sound-wave frequency of vibration that is twice that of the lower note.
The process of naming an interval involves finding the distance between two notes as they appear on the staff. To find out the interval, just count every line and every space in between the notes as well as the lines or spaces.
The seven intervals that are considered consonant are:
- Minor Third
- Major Third
- Perfect Fourth
- Perfect Fifth
- Minor Sixth
- Major Sixth
The five dissonate intervals are:
• Minor Second
• Major Second
• Minor Seventh
• Major Seventh
The five dissonant intervals produce “unpleasant” sounds that disrupt the flow of music. Note that “unpleasant” is a relative term in this case because what we are talking about is a desired effect.
Dissonant intervals might also be described as “tension producing.” After these intervals are heard, the expectation is that the music will move along to a more stable chord. The latter is called “resolution” or “resolving the dissonance.”
The bottom line is, these unpleasant or tension-producing intervals are used to create exciting and interesting effects in music. It’s a way to make music less boring and more innovative – even daring and challenging.
Certainly, there can be too much of a “good thing.” Some avant-garde or cutting-edge artistic compositions take dissonance to an extreme to create music that, for some people, would not fit the definition of music at all.
As an example of a musical piece that most would consider “disturbing” because of an extreme application of dissonance, listen to Threnody for the Victims of Hiroshima by Polish composer Krzysztof Penderecki:
It must be remembered, however, that art is not necessarily “pleasant” in intent. Some music is designed to make us feel raw, negative, or unpleasant emotions. If it does that, as does Penderecki’s ‘Threnody,’ then it has achieved its goal.
Harmony in music is based on chords. They are groups of notes built on something called triads. They come in two forms, major and minor chords. All chords have at least three notes. There can be more notes but sometimes notes are left out and are only “implied” by the harmony.
With block chords, all the notes in the chord are played simultaneously. However, the musician may choose to play the chord notes separately with a bit of overlap but quickly enough to make it sound like one chord. The latter are called arpeggios or arpeggiated chords.
When a series of chords are played one after the other it is called a chord progression.
Thus, chords that contain dissonances are called “unstable.” After we hear them, the mind naturally expects the disruptive chord to be “resolved.” When an unstable chord is followed by a consonant chord, the dissonance is resolved.
These kinds of “change-ups” are what can make music exciting, thrilling, and more interesting than long consonant compositions which can start to sound like elevator music after a while. (For some listeners, anyway).
The human mind naturally craves novelty, perhaps especially so in music. Dissonance is a way to achieve that.
The Theory Behind Dissonance
People who study musical theory have put forward many theories about why dissonance is a desired effect in music. This gets into some pretty complex territory, and one need not necessarily understand the underpinnings of all this to simply appreciate and enjoy music.
However, culture certainly plays a role in the preferences for consonant and dissonant forms of music. Musical preferences are closely tied to the cultural attributes of the people who listen to and create their own music.
Just consider the cultural differences between bluegrass music and heavy metal. Anyone would quickly see a lot of differences between an audience gathered at a bluegrass concert and a crowd gathered to hear such bands as Metallica or Megadeth.
A smokey jazz club bears stark differences from a concert hall where people gather to hear Beethoven’s 9th Symphony.
Nature itself also plays a role. Human beings create music partially inspired by the sounds of nature, such as the singing of birds or the tumbling chatter of a rocky stream. Many bids sing harmonious consonant songs while others present jarring calls of dissonance. Three examples of the latter are:
We’ve only touched on the general notions of what makes up musical dissonance. Just remember that, in simplest terms, consonant notes "fit" together better than the sound of dissonant notes.
Dissonate noted go against the grain to disrupt the harmonious sounds saves of music to create an artistic effect that can be jarring and “unpleasant” but can also make for deliciously provocative and pleasing effects in music.
One might say that consonant notes are the sugar and dissonate notes are the spice.