A note can be simply described as one single unit of sound that is played on your violin. For example drawing your bow across an open string means you have played one note. A music piece is nothing but a stream of various notes played for different lengths of times, in different levels of loudness, and with different bits of pauses in between them.
There are numerous ways in which people across the world represent music on paper. For example in carnatic music, notes are written as syllables ‘Sa Ri Ga Ma Pa Dha Ni’. In western music, notes are written as letters ‘C D E F G A B’. And then there are guitar tabs, sheet music and so on. No one way is better than the other, but some have become way more popular than the others and evolved to be universally recognized. One such way is the sheet music. Which is more commonly used than other representations (including on this website). For the purpose of explaining music notes in this article, we will discuss the notation where notes are represented using the English alphabets ‘C D E F G A B’.
What is a Note?
Basically, sound is vibration of air that hits your ear drum. For example when a drum is hit, it makes the surrounding air vibrate and the vibration gets carried around in all directions as a sphere around the drum. Like when you throw a stone in a pond, it creates waves that travel around it in circles. The number of waves generated per second is called the frequency of the wave. When the vibrations hitting our ears are between 20 Hz and 20 KHz, our brain interprets it as sound. Means the number of vibrations are between 20 times per second (20 Hz) to 20,000 times per second (20 KHz).
Any sound we hear, is a wave with a frequency. Musical notes are specific frequencies, for which we have assigned a name. For example, 262 Hz frequency is called C (the middle C key on a piano), 440 Hz frequency is called A (the open A string on a violin). This ‘A’ is called ‘A4‘ (because it’s the 5th A key on a piano and the numbering starts at zero). No matter in which instrument you’re playing or even if you’re singing, the frequency is always 440 Hz for the A4 note.
Musical notes are specific frequencies, which are of particular interest to us and for which we have assigned a name.
There are 12 notes in an octave represented using 7 letters, and the symbols for sharp ( ♯ ) and flat (♭). The following are the notes names in western notation –
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| C | C ♯ (or) D♭ | D | D ♯ (or) E♭ | E | F | F ♯ (or) G♭ | G | G ♯ (or) A♭ | A | A ♯ (or) B♭ | B |
What Comes After B?
After B, it is again C, C#, D and so on. The 12 notes keep repeating. Each set of 12 notes is called an octave. The octave repeats itself again and again as the frequency keeps increasing. When a situation requires that we differentiate between the same note from different octaves, the notes are be written as C1, C2 (or C1, C2) etc.
Why Do They Repeat?
Because every time the frequency increases to exactly it’s double, the sound has a striking similarity. C1 and C2 both sounds have harmony. To understand, you can simply play C1 and C2, and then listen to C1 and A1 (or any other note except C). Repeating the note names for every octave is natural because our brain interprets (or reacts to) 880 Hz and 440 Hz mostly the same way. As frequency increases from C, and goes step by step through D, E and so on, the ‘feel’ of the sound keeps changing and then when the frequency reaches double of the starting point, the ‘feel’ of the original sound returns. That’s why we call this doubled frequency too as C. The same with A1 and A2, B1 and B2, B2 and B3, B3 and B4 and so on.
Why 12 notes? Why only 7 letters?
This is just convention. Different systems across the world and over history divided sounds into different number of notes. Indian music for example, has 22 notes (called ‘shruthi’). In western notation, it was decided to divide into 12 notes. The divisions itself were not arbitrary, it is just that different parts of the world came up with whatever systems they felt were apt, and the western notation became one of the most popular ones. There are different mathematical and psychological explanations given as to why certain frequencies were selected to be prominent and marked as specific notes, but the explanations vary and hence the various ways of splitting up an octave. Factors like convenience of communicating music, tuning instruments, and so on have played roles in the music notations that exist currently. But mostly, it is just convention and what became popular.
Using 7 letters to represent 12 notes, for example, is because of convention of using ‘diatonic’ scales – where a piece of music strictly uses only 7 notes from each octave. For example, a musical piece in the key of C Major, will use only C, D, E, F, G, A and B. Any occurrence of other notes (like C♯), would be considered an ‘accidental’. Similarly, a song in G Minor, will use G, A, B♭, C, D, E♭ and F – not the other notes. In such a piece, we will mark that all Bs and Es in the piece are flat (♭) in the beginning of the piece and then write the song itself with just the notes. Not mentioning with each B and E that they are flat. Since for a considerable time of history music was written using such diatonic scales, with only 7 notes, the system evolved to using only 7 letters to represent music.
Why does it start with C rather than A?
It is again historical and not technical. The A minor scale was considered significantly more common than other scales. So the first note of that scale was named ‘A’. So the most common scale at that time was A, B, C, D, E, F, G. 7 first letters from the alphabet as we would expect. But as time passed by, the C major scale became more widespread and central to western music. And it appears to us as if the notes begin with C. The truth is it doesn’t ‘start’ or ‘end’ – the notes are like a circle of 12 notes. When we talk about C Major, we start with C. When we are talking about A minor, we start with A. When we are talking about music in B♭minor, we start with B♭.
It’s just that most of the time beginners of music are introduced to pieces in C Major scale, even before they know what a scale is. So naturally we feel like the notes start with C.
What are Sharps ( ♯ ) and Flats (♭)?
Although, we have divided an octave into 12 notes, as you saw, we use only 7 letters to represent them. Even in the sheet music notation, we use dots on the lines, only to represent 7 notes for each octave. We need a way to represent the other 5 notes. We use symbols sharp ‘♯’ and flat ‘♭’ to add notes using the same set of 7 alphabets. so between C and D, we insert a C♯. Between D and E, we insert a D♯ and so on, in five places. So ultimately the 12 notes (as given in the table above) is formed. For the notes that have two names (eg., D ♯ (or) E♭), what we call that note depends again, on the scale that we are playing. When we play B-flat major scale, we call that note E♭. When we play B major scale, we call that same note D♯.
Sharp means higher frequency. So the following note with higher frequency than C is called C#. C-Sharp because it sounds ‘sharper’. Similarly preceding note with lower frequency, which sounds ‘flatter’, is called a flat of that note. Like E♭which sounds a bit ‘flatter’ than an E.
Why Can’t We Simply Use 12 Alphabets?
This is again, just because of tradition. There are various ‘types’ of scales, but the one that gained the most popularity is the ‘diatonic’ scale. Not going deeper into scales, a diatonic scale is where we use 7 notes to represent a scale. If we used the 12 alphabets ranging from A to L to represent music, diatonic scales would be confusing to represent. Each scale would have a different set of 7 letters between A and L. C Major would be C, E, G, H, J, L, B! Instead, if we use only 7 alphabets and symbols for sharps and flat, C Major is neatly – C, D, E, F, G, A, B. It’s easier to remember which notes are flat and sharp on each scale rather than different sets of alphabets for different scales. So that’s what we do. Because at some point in history (and even in present) we made a lot of music with diatonic scales, we adopted this particular system rather than a 12 alphabet system.
This is how many things in music, generally are. Music by itself doesn’t need to follow rules or have forms. But we do these things (like using scales, writing notes in specific ways etc.), just for convention and convenience. In future, we might expand our knowledge and create a new way of representing music. But right now, the western notation is one of the most popular ways and just easy enough to get started.