Welcome back to Wired Theory, a weekly series by Wired Guitarist. I’m glad you all have been enjoying the past couple articles. This week we’re going to start diving into how notes work together.

I’m talking about intervals. Not the awesome music project headed by Aaron Marshall, but rather the space between pitches. There are many types of intervals, and we will get to those as we go on.

As a disclaimer, we are referring to the Western music theory ideology where the smallest interval we have is a semitone or half-step. No microtones will be discussed here

Naming Intervals

Before we can start building chords, scales and writing songs, it’s always a great idea to learn how all of these are related. We’ll learn how to build chords and how notes work to harmonize each other.

For starters, you have melodic intervals, which refers two notes played in succession, and then you have harmonic intervals, which are played simultaneously. Today we will be discussing in terms of both.

Let’s refresh on note names; you have 7 notes in the musical alphabet:

  • A B C D E F G

As well as your 5 sharps and flats:

  • A A#/Bb B C C#/Db D D#/Eb E F F#/Gb G G#/Ab

This gives us 12 total notes.

This is crucial.

The space between each of the 12 chromatic notes is called a “half-step” or “semitone”. When applied to the guitar, every fret is one half-step. Like wise, the “whole-step”, or “whole tone” is the space between two consecutive chromatic notes. It’s important to know this when we build scales.

The proper naming scheme for intervals tells us two properties of the interval: its quality (perfect, major, minor, augmented, diminished) and its number (unison, second, third, etc.).

These names describe not only the difference in semitones between the upper and lower notes, but also how the interval is spelled.

The number of an interval is the number of letter names it encompasses or staff positions it encompasses. Both lines and spaces (see figure) are counted, including the positions of both notes forming the interval.

What do the 5 qualities tell us? They help us to identify the number of semitones in each interval along with the number, and they follow a pattern:

  • Perfect Unison (same note and octave)
  • Minor 2nd (half step)
  • Major 2nd (whole step)
  • Minor 3rd
  • Major 3rd
  • Perfect 4th
  • Perfect 5th
  • Minor 6th
  • Major 6th
  • Minor 7th
  • Major 7th
  • Perfect Octave

Since there are 7 different letters in the alphabet, we use numbers 2-7, (with 1 being the unison), to stand for the 7 possible notes.

As for the other intervals, they are used for enharmonic intervals and notes spanning the same number of semitones but a different number of spaces on the staff.

Context

Augmented intervals are one semitone larger than a perfect or major intervals, while having the same interval number (i.e. encompassing the same number of staff positions). Likewise, Diminished intervals are one semitone closer than perfect or minor intervals of the same interval number.

For instance, an augmented third such as C–E♯ spans five semitones, exceeding a major third (C–E) by one semitone, while a diminished third such as C♯–E♭ spans two semitones, falling short of a minor third (C–E♭) by one semitone.

Seem confusing? Don’t fret, here’s a chart to help you out:

Music Intervals

As you can see, depending on the actual notes and spaces on the staff, an interval can have a different name even though it sounds the same aurally.

You notice how there is a space where 6 semitones are in the chart?

Well, when you approach two notes 6 semitones apart (lets say C and F# or C and Gb), you reach a tritone. Why is it isolated from the others? Well, historically speaking, it’s neither a major nor minor interval, and can only be described as a diminished fifth or augmented fourth. The common term is tritone, and you won’t hear these as often, because they were associated with the devil back in the early days of contrapuntal music.

Pretty metal, huh? Well, the first time the tritone was used in popular music was in Black Sabbath’s “Black Sabbath”, which further associated metal with the occult.

 

As for incorporating intervals into your music, check out Cannon McDonald’s upcoming video and get ready to shred. Stayed tuned next week for when we’ll start learning how to use scales and modes properly with our new knowledge of intervals!

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This article written by community content contributors Zack Seif. Zack is a classically trained professional musician, currently at the helm of his solo project, Regression. 

 

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