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Ever since I started learning Guitar, I have been wondering what makes music so pleasing to our ears. And what makes a chain of tones a music which, if played independently, has no charm. My guitar tutors taught me lessons such as “you need to come back to the Key when you conclude your melody.” I obeyed them; because they worked all the time. We have been following such rules to play and create music. In this article, I will describe my findings on why those rules are rules.

This article requires an entry-level knowledge of the western music theory. So readers of this article are supposed to know the following:

1. notes in a musical keyboard and their names
2. sharps and flats
3. what a musical scale is

If the above terms are new to you and still you want to continue reading this article, I would suggest you to learn them from the Connexions Music Modules. Also read Music Theory Wikipedia page and from Ricci Adam’s musictheory.net.

In addition to knowing the above it is also assumed that, when you hear the same musical note twice–one after the other, you must be able to make out that they are the same. And when someone plays your favourite tune on her guitar and she slips a note or two, you can clearly make that out too.

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Well, let’s dig into the matter. For the sake of simplicity, we will discuss melodies to generalise music as melodies are music in the simplest form.

When you listen to a melody you can feel the following (recall your favourite melody; if nothing comes to your mind listen to this AirTel jingle):

It starts and a phrase is developed
It continues that way taking us to ecstasy
It starts a kind of coming back
It reaches home (we feel completion)

My curiosity was why this happens and what makes the mind enjoy the progression (the sequence in which those musical notes are played).

To proceed further with the discussion we need to understand a major concept in music called Tonal Interval.

Tonal Interval

Tonal interval is the “musical distance” between two notes on a keyboard. The tonal interval between any two adjacent notes is called a “semitone” or a “half step”. Similarly the distance between any note and the third from it is called a “whole tone”. For example the interval between the note C and C^# is a semitone or a half step. The interval between the note C and D is called a whole tone or a full step. This way you can enlist the distance between any two tones in the keyboard.

Try playing all two-note (one after the other) combinations. Start with two notes of one half step apart and then a full step and then one and half step and so on. While doing so give attention to how each pair sounds like and feels like. You would notice that certain combinations (or the transition) sounds better than another. Likewise certain combinations sound horrible or unstable.

Well, you just learned one of most important fundamentals of music. Now let us understand two aspects of tonal interval.

Consonance and Dissonance

The origin of the word Consonance is from the Latin word “consonare” which means simply “sounding together”. But in the theory of music this is used to refer a tonal interval that sounds stable, pleasant and completely at rest. The most familiar example to illustrate a consonant interval would be the “ding-dong” of door bells or wall clocks.

If you try to figure out the interval of the “ding-dong”, most likely the interval would be two whole steps (this interval is called major third and is used in all dual tone applications around us such as door bells, car horns, etc.). That means if you start with E (“ding”) and the note C (“dong”) which is two whole steps down makes the combination. Now if you play D^# (which is nearer to C by one half step) instead of E, you will note that it doesn’t sound as sweet. Repeat this experiment by reducing the interval by one half step each time. The pleasant sounding interval will become increasingly harsh as you proceed and you will hear the harshest when you play the “ding” just one half step away (i.e. C^#) from “dong”. This harshness is the opposite of Consonance and it is called Dissonance.

So the interval between any two notes in the twelve-tone system is identified to have a certain degree of consonance or dissonance. See the following table which describes the quality (degree of consonance or dissonance) of all possible tonal intervals in the twelve-tone system.

Note	Tonal Distance/Interval	Quality
C	none	pure consonance
C#	half step	very dissonant
D	one whole step	dissonant
Eb	three half steps	mild consonant
E	two whole steps	very consonant
F	five half steps	pure consonance
F#	three whole steps	ambiguous
G	seven half steps	pure consonance
Ab	four whole steps	mild consonance
A	nine half steps	very consonant
Bb	five whole steps	mild dissonance
B	eleven half steps	very dissonant
C	six whole steps	pure consonance

Please note that whether the consonance and dissonance effects of tonal intervals are absolute/universal or enculturated is a subject for debate. However here we just need to know that each tonal interval has an associated degree of consonance or dissonance to understand the concepts being discussed here.

Also note that the three-whole-step interval is neither a consonant or a dissonant. This interval is called diminished fifth. I have been told that diminished fifth (also known as devil’s interval) was banned in early church music because of its ambiguous nature. While playing this interval it does give a tensed and horrible feeling. This interval was first used in a song by Black Sabbath and then several bands after that.

This consonance and dissonance in varying degrees appear in a melody as it progresses. As we have seen earlier, our mind becomes restless when the melody proceeds to a dissonant interval and will feel peace when it enters a consonant interval. This sequential progression of consonant and dissonant intervals of varying degrees produces a sensation of movement through time. It is the combination of dissonance and consonance, tension and relaxation that defines this movement. This movement give a musical direction to the melody.

This is somewhat similar to what we feel when we read a novel. The thread of the story passes through tensed situations (dissonance) during which our mind becomes curious and long for a resolution (consonance) which we feel when we reach the phrase “they lived happily ever after.”

Now let us experience a simple progression to illustrate this. Try playing the following note sequence in keyboard.

(Press and hold each key for one second. Keys are numbered for easy understanding.)

C[1], D[2], E[3], E[3], D[2], C[1]

As we move from note to note, we feel respective intervals. An interval can either be dissonant or consonant. Here we can experience the following with the progression:

C: –
D: dissonant (tension)
E: very consonant (some what relaxed)
E: very consonant (some what relaxed)
D: very dissonant (climax)
C: pure consonance (resolution)

When we reach the last note C, we feel the that the melody came to a conclusion. Now let us see how we can make this simple melody a little more interesting. Try this sequence.

(Press and hold each key for one second. Keys are numbered for easy understanding.)

C[1], D[2], E[3], D[2], B[0], C[1]

(Notice that the note B is numbered zero because it comes before the note C)

You would agree that the this sequence sounds more enchanting than the previous one. This is because of the musical motion created by the sequence of tension and relaxation (dissonance and consonance) is more vivid in this sequence. Let us analyse it more carefully.

Have a look at the note sequences once more. Both the sequences give a feel of resolution by returning to the note C. But the second sequence is definitely sweeter than the first one. This is because, we simply postponed or delayed the resolution by playing the extra note B which intensified the drama, prolonging the mystery and sustaining the listeners attention! This is how sweet melodies are created.

It would be interesting to note that its is the interval between the notes is what creates music. Next time when you listen to a sweet melody remember that your mind is being tingled by those tonal intervals! And the background score in the movie is playing a dissonant interval when the villain shows up!

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What we discussed here is the music in its simplest form. The songs and compositions we enjoy are more complex than simple melody. It contains harmony which brings in multitude of intervals at the same time. The effect of which is easier to feel than analysing it. But the fundamentals remain the same: tonal intervals, consonance, dissonance and the influence and the resulting feeling effected in our mind by a particular progression.

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Bibliography

1. Pen, Ronald, Ph.D., Introduction to Music, 1992, McGraw-Hill Co. Singapore.
2. http://en.wikipedia.org/wiki/Interval_(music)
3. http://en.wikipedia.org/wiki/Consonance_and_dissonance
4. http://www.music-cog.ohio-state.edu/Music829B/notes.html