A closer look into intervals, the Semitone

As previously mentioned, we have several types of intervals. So far we have looked at Major, minor and Perfect interval types.

For now let's go over the Major and minor second!

The Major second, turns out, also has a very popular name. A Tone! Depending if you speak British or American English you'd refer to the Major second as a “Whole Tone” or simply as a “Tone”. Both terms, Whole Tone and Tone, mean the same thing and are sometimes used interchangeably depending on context. But at the end of the day we're talking about a Major 2nd.

On the other hand, a minor second also has a fancy set of names. A minor 2nd is also called a “Half Tone” or a “Semitone”.

The name gives it all away, A half tone is half of a whole tone. Another way to say the same thing is that a semitone is half of a tone.

A related topic comes to mind! Remember that we used flats to lower notes and turn Major intervals into minor intervals? Well another way of thinking about adding a flat symbol to a note or scale degree is that we are lowering the pitch by one semitone (or by one half tone).

Interval Explanation
b2 A Major second lowered by a semitone
b3 A Major third lowered by a half tone
b6 A Major sixth lowered by a minor second

What I want you to realize is that lowered by a semitone, lowered by a half tone and lowered by a minor second are all the same thing. That's why the interval name is just a number with a flat symbol before it. To flat a note or interval or scale degree is to lower it by a semitone.

Semitone in music recording and production programs is labeled as “St”, just a quick trivia titbit!

You probably have heard a musical scale where people sing Do Re Mi Fa Sol La Ti. This is one way to refer to the scale degrees, in this naming system called Solfege we name the 7 notes from a Major scale using those music-y sounding names.

Major Scale degrees Solfege note names
1 Do
2 Re
3 Mi
4 Fa
5 Sol
6 La
7 Ti

You'd probably heard those names from The Sound of Music. A Musical turned cult classic movie from 1965.

It's not very important that you memorize the Solfege note names but we will use them for now as place holders for the actual note names.

So on a Major scale we have 7 notes – Do, Re, Mi Fa, Sol, La and Ti – But in reality there are more than 7 notes, in fact we have 12 distinct notes..... So? Where did the other 5 notes go?

To easily find them let's look at a piano:

In here we can see that the first note is labeled C3, a bit further after that we have C4 and C5. The piano is laid out in such a way that we have white colored keys and black colored keys. The white and black keys follow a pattern that repeats.

We have 2 black notes bunched up together and then 3 black notes in a group. This pattern repeats, 2 black notes then 3 then 2 then 3 and so on.

So again, we have 7 notes (Do, Re, Mi...) out of a total of 12, so we have 5 notes left to discover.....five is the hint of the century!

The pattern repeats, 2 black notes then 3....2 then 3. Two and three.... EQUALS FIVE OMG. So yeah quirky manners aside these 5 black notes on they keyboard are the 5 that are missing from the total of 12 notes.

And these remaining 5 notes don't have names by themselves, they are named by adding sharps and flats to neighbor notes.

So the first note, labeled C3, is Do. So the next note, a black key, is called Do sharp. Remember that to sharp a note is to raise it by 1 note and to flat a note is to lower it by 1 note.

This leads to an interesting realization. If we look at the white keys not all of them are separated by the same distance.

The distance between the first white key and the second white key is of 2 notes. 1 black note and 1 white note.

To count the distance between two notes we start at the note we're counting from, this is note zero, then we count until we arrive at the note we want to figure out the distance to. So to figure out the distance between the first 2 white keys we start at the 1st white key (0) then we go up to the first black key (1) and we arrive at the 2nd white key (labeled 2).

So the distance between the first and second white notes is two semitones. Yep, each note going up or down equals 1 semitone.

But look at the distance between the 3rd and 4th white keys:

The distance between the 3rd and 4th white keys is only 1 semitone!

And the same is true for the distance between the 7th and the 8th white keys.

So between the 3rd and 4th white key there's 1 semitone, and there's also 1 semitone between the 7th and 8th white key. This pattern is super important!

Take in mind that all other white keys is separated by 2 semitones, test it out for yourself!