4. Notes and Scales

What is a note?

A note represents a sound. More precisely, it represents a frequency. To fully understand this, let's take a look at what sound really is.

What is Sound Really?

When we listen, we perceive the vibration of the air. In the graph below, the small blue dots represent the air particles.

When we play a sound, the speaker's diaphragm vibrates. This vibration moves the air particles. The movement creates areas with more air particles and areas with fewer particles.

We represent this with a wave. You can see it in the graph below the air particles.

The peaks of the wave represent areas with higher particle density. The valleys represent areas with lower density.

We can also represent the movement of the speaker with a wave. The peaks show when the speaker pushes outward. The valleys show when it contracts.

These air vibrations reach your ear and make the eardrum vibrate. This vibration is transmitted through the ear. It makes tiny "hairs" in the auditory cells vibrate. These cells send electrical signals to the brain. Finally, the brain works its magic and converts these electrical pulses into the perception of sound.

You can interact with the graph by pressing the piano keys. Remember that each note represents a frequency. For example, the note C2 (Do) on the piano has a frequency of approximately 65 Hz.

Hertz (Hz): Unit that measures vibrations per second. 65 Hz means that the wave goes up and down 65 times per second. In other words, your speaker's diaphragm vibrates 65 times per second. You could say that the note C2 is what you hear when your speaker vibrates 65 times per second.

Higher notes have higher frequencies. This means that the wave vibrates faster. Your speaker also vibrates faster. Play C2 and C3 on the piano and compare them. You will see that C3 vibrates twice as fast as C2.

Now comes the interesting part: When one wave vibrates twice as fast as another, our brain interprets them as the same note. It's just that one is higher than the other. That's why C2 and C3 have the same name (C). The number indicates which one is higher.

You can observe this difference in the following image, where we see that C3 has double the frequency of C2 and that makes us perceive them as the same:

Does this have any practical use? Yes. This is how a guitar works. If you pluck a string, it produces a note. If you press that string with a finger to shorten its length by half and pluck it again, the note will be the same but higher in pitch. In fact, there is a metal bar on the guitar to easily identify this point.

The 12 Notes

We already know that by doubling a frequency, in this case from C2 we get C3, which is the same sound but higher. So we already know where our first note comes from!

But what about the other notes? This is where the fundamental decision of Western music comes in: we divide the frequencies between C2 and C3 into 12 equal parts. This gives us 12 new notes. In other words, we divide the range between 65 Hz and 131 Hz into 12 parts.

We will represent C2 and C3 as 2 black circles. Remember that they are the same sound. They are marked in yellow because they are the 2 extremes of our frequencies.

By dividing this range into 12 equal parts, we obtain 12 new notes. I will show you their 2 ways of naming them, but you don't need to know their names for now.
C, C♯, D, D♯, E, F, F♯, G, G♯, A, A♯, B, C
Do, Do♯, Re, Re♯, Mi, Fa, Fa♯, Sol, Sol♯, La, La♯, Si, Do

These 12 notes are present in all instruments: piano, violin, flute, guitar, trumpet... They all use only these 12 notes.

If we added more circles to the left or right, they would be the same notes but higher or lower. To get more notes, we would have had to make more divisions. But in the history of Western music, it was decided that 12 was a good number. All the songs you hear (classical music, rock, electronic...) are composed of those 12 notes.

The Scales

Now that we know the 12 available notes, an interesting question arises: Do we use all of them in a song? The answer is no. But why not use them all 🎹🤩🎹?

It's like when you paint a picture; you don't use all the colors available. If you want a cheerful painting, you use bright colors; if you want a sad painting, you use darker colors, or soft colors if you want it to convey tranquility. You rarely use all the colors in the same painting; you choose a color palette depending on the feeling you want to express.

The same happens with music: from these 12 notes we only choose some depending on what we want to convey. Instead of a color palette, here we talk about Musical Scale.

For example, these are the notes that are chosen in most of the music you listen to. It's called the Major Scale:

You might wonder: What are they 🧐? C, A, G...? All I see are black circles ⚫️🤪? Here’s the trick: the name doesn’t matter. What matters are the intervals between each selected note. The intervals between each note we choose are what give style to our scale.

In this case, the pattern is 2-2-1-2-2-2-1. We start on C2, 1st circle, make 2 jumps and select the 3rd note. We make 2 jumps again and select the 5th note. Now we make 1 single jump and select the 6th circle... In music schools, instead of 2-2-1-2-2-2-1, they call it W, W, H, W, W, W, H (where W is Whole step and H is Half step). You often hear music students quietly reciting before an exam... Major Scale... Whole, Whole, Half, Whole...

It doesn't matter if you had started on a different note. As long as you make the same jumps, the scale will be the same. It's like going up and down a staircase. If you go up 2 steps, down 1, up 3, and down 2, it doesn't matter if you started on step 10 or step 34, the movement you've made is the same.

This palette/scale is often used for cheerful or lively songs.

Now let's look at other scales... 🎨

Minor Scale - 2-1-2-2-1-2-2
Unlike the Major scale, this scale sounds more muted and less vibrant. While the Major scale is often used for cheerful songs, the Minor scale is typically used for sadder songs. Although this is not always the case.
The Major scale and the Minor scale are the two that are commonly used in current music.

Blues scale - 3-2-1-1-3-2
Fíjate cómo, al seleccionar otra separación de notas, obtenemos un estilo de música blues.

Double Harmonic Scale - 1-3-1-2-1-3-1
Esta escala tiene un estilo árabe.

In Sen Scale - 1-4-2-1-4
Esta tiene un estilo japonés.

Once we select our note palette (we will usually choose notes from the Major or Minor scale), we can start creating a sequence of notes to compose our song.

How do these scales sound?

If you press the blue play button, you will hear a well-known song in each of the scales. You will see that the notes we play are NOT the same, because in each scale we chose different notes, but what remains the same in all examples are the positions of the notes we play in each scale (3rd black circle, 4th black circle, 5th, 5th, 4th, 3rd...) The change of scale will make the color of the song change, but by playing the same positions in all of them, it will make us identify it as the same melody in all cases.

Major Scale:

Minor Scale

Blues scale

Double Harmonic Scale

In Sen Scale

It sounds better in the major scale because that is what it was composed for. But the general idea we need to keep in mind is that the specific notes don't matter. To select what "color" our melody will have, the distance or jumps between the chosen notes are important. And for our melody as well, within those chosen notes, how much we move up and down from one note to another matters.

If you're up for it, you can try creating your own scale!