Consonant, Dissonant and Perfect.

Consonant, Dissonant and Perfect

Many music theory books oftentimes only talk about consonant and dissonant sounds, but there is a 3rd harmonic sound that is oftentimes neglected in music theory books. We will discuss these 3 harmonic sounds here.

Anytime you play 2 or more notes together, these notes combined create a new sound. We can call the new sound a “harmonic sound” because it is the result of how the combined notes interact with one another. Sometimes these notes will vibrate pleasantly together, and sometimes the vibrations will clash against one another.

When the 2 or more notes vibrate nicely together, that is called “consonance”.
When they clash, that is called “dissonance”.

We use the same word to describe the harmony between for example people. When 2 people rub each other the wrong way, we say that they have a dissonant relationship or that there is dissonance in their interactions.

I have heard the word “disharmony” being used before as a synonym for “dissonance”.
I prefer the word “dissonance” because “disharmony” after all is just some kind of “harmony”: it’s a dissonant harmony.

The words “consonant” and “dissonant” refer to the sound that is created when multiple notes sound simultaneously.
“Consonant” is described as pleasant and sweet while “dissonant” is described as “tense and harsh”.

  1. Consonant

    The intervals that fall in this group are:


    Some of the words people use to describe this sound are:
    Sweet, sugary, honey, sugar, lovely, kind, pleasant, enjoyable, friendly, warm, calm

  2. Dissonant

    The intervals that fall in this group are:


    Some of the words people use to describe this sound are:
    Vinegar, pepper, spice, angry, rubbing the wrong way, tension, bite, sour, harsh and unpleasant.

  3. Perfect

    The intervals that fall in this group are:


    Some of the words people use to describe this sound are:
    Neutral, hollow, transparent, not a whole lot of personality, no color,

This explains why the most important notes in a chord are always the 3rd and the 7th. These are the notes in the chord that give the chord its color, its sound, its identity.

The 3rd adds the loveliness and sugar to the chord sound, the 7th adds the bite and tension to the chord.

The root (unison, octave) and the 5th in the chord add some “foundation”, to the overall chord sound, but they don’t contribute much to the actual sound and color of the chord.
That is because the root and 5th fall in the group of perfect intervals, which have a more neutral, transparent sound.
These notes don’t color the chord all that much.

You can omit roots and 5 in chords, and it will still sound like that chord.

The Importance of Dissonance

Sometimes students slack on their practice of 2nd intervals. Some of their arguments include: “I don’t like the sound”. “When will I ever use this?”

You might think to yourself: “Why learn 2nds and 7ths? Why would anyone want to have unpleasant tension or harshness in music?”

After all: it can actually also be physically unpleasant. As an example: play a minor 2nd up the neck, on the top 2 strings, on your bridge pick up. Feel free to crank your amp.
If you do this at a louder volume, on your brightest pick up setting, you will concur with me that it kind a hurts the ear and sounds really quite unpleasant.

Yet, music would sound boring without those sour notes and intervals. It would lack direction and motion. Without tension, there is no story telling.
After all, music, as is all art, is like life itself: a constant forward motion from tense moments into joy.

Say you have something really crappy or stressful happening in your life that you need to try to resolve. You keep putting it off because it worries you, you have a hard time sleeping because it keeps you up at night, and you can’t get yourself to take care of it. Then comes the day when you have to get it done, you get to it, and get it over with.

That event created forward motion and direction in your life.
As long as you didn’t resolve it, your life was stagnant. The moment you actively engaged in finding a solution: you learned, grew, got stronger, smarter, wiser and came out ahead.

Now you are better equipped to handle the next dissonant situation that will come up in your life at some point. The dissonant event, required a resolution, and created forward motion in your life. That momentum also made your life more interesting.

You might think “more interesting”? “I much rather prefer a boring, easy life!”
That might seem like a good point. However: there is a lot one misses out on with that frame of mind.
Here’s why:

The more stressful that event was, the bigger the relief, joy and happiness you feel afterwards.
The toughest obstacle you ever had to resolve or overcome, is also the thing that gave you the greatest joy and satisfaction once you resolved it.

The feeling of joy one feels coming out of a stressful situation, is all the greater the more stressful that situation was.

It is normal that these 2 feelings balance one another out. After all: your biggest obstacles are also your biggest achievements once overcome.

Another example: the harder you worked… the deeper the joy you feel during your vacation. You then feel like you REALLY earned that vacation and the time off feels all the sweeter and all the more pleasant.

The same is true in music: the more tense a chord sounds, the sweeter and stronger the resolution sounds. THAT, is why you cannot create great art without the tension. Great artists know that, and play around balancing the tense note combinations and chords with the pleasant ones.

That is one of the reasons why jazz musicians for example, love adding b9’s, #9’s, altered 5ths and so on to their dominant chords. Those tensions added to the V7 chords, make the resolution of the V to the I chord all the more profound and all the sweeter.


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