An interval refers to the distance between two notes. Do you remember the twinkle twinkle little star song? You can think of it, or you can hum it with your mouth. Can you feel the pitch rising and falling? Our goal is to be able to instantly identify, in which direction and by how much, a note changes based on the other note, and be able to name it.
When you listen to the intervals and start reading each of the names, pitch training begins. Before explaining, Check the table below with C as the root note.
An octave is represented by 7 degrees, and the root note itself is called 1st degree. If C is the root note, the 1st degree is C. And the 2nd degree is D, the 3rd degree is E, the 4th degree is F, the 5th degree is G, the 6th degree is A, and the 7th degree is B. Naturally, 8th degree is C above an octave.
An octave consists of 12 semitones. As shown in the table above, all intervals have names consisted of quality and degree. To help you understand, let me explain the simple rules.
There's Perfect(P) interval at 1st, 4th, and 5th degrees. If you go down a semitone, it becomes a Diminished(dim) interval, and if you go up a semitone, it becomes an Augmented(Aug) interval.
There's Major(M) interval at 2nd, 3rd, 6th, 7th degrees. If you go down a semitone, it becomes a minor(m) interval, and if you go up a semitone, it becomes an Augmented(Aug) interval. If you go down two semitones, it becomes a Diminished(dim) interval, but it's not used often, so it'll be okay to know it as a theory. (Because Diminished 3rd is the same as Major 2nd.)
We found out what the intervals are and what they are called. Now we will develop the ability to identify each interval in any situation, regardless of the root note. There are programs to count and name the intervals after listening to the sounds. Shall we do it step by step?