# Understanding Intervals Part I

This is my second article in a series covering some basic concepts of music theory, concentrating on topics relating to musical harmony. In this article I’ll be covering the concept of Intervals. It’s important to learn about intervals since they are the most basic building block of harmony.

The term “interval” is used to describe the pitch distance between two musical notes, whether those notes are played together or consecutively.  When someone says “interval” think of it as another word for “musical distance”. In this article I’ll be explaining the names of these distances and also providing many examples of how these musical “distances” are used in music.

Musical distances are often described in terms of a unit called “steps”. First, I will define what is meant by a “step” as it pertains to music. Then I’ll describe intervals using the “step” as our unit of measurement.

## What are “steps”?

To describe steps we will start with the smallest unit of measurement called the half step.  A “half step” is the distance between two adjacent keys on a piano such as C to C#, or B to C

On fretted instrument, such as guitar or bass, a “half step” would be the distance of 1 fret.

A “whole step” is the distance of two half-steps.  On a piano this would be the distance of three adjacent keys (two 1/2 steps), such as C to D, or Ab to Bb. On guitar/bass this would be the distance of 2 frets.

Now that we have these basic units of whole step and half step defined, we can use them to describe musical “distances between notes”.

## Octave and Unison

In western music (i.e. music that had it’s origins in Western Europe) an octave is divided up into 12 half steps. If you start at any key on the piano, and go up to the next adjacent key (a 1/2 step), and continue in this way 12 more times you will end up on the same note in the next register. We call this distance of 12 half-steps an “octave”.  The staring note and ending note are the same note (for example “C”) but they are said to be one octave apart.

The term “octave” is used to describe notes of the same musical pitch but in different registers.  It’s easy to visually see the interval of an octave on the piano.

On guitar, the octave can be played in a few different ways. Here are a few different fingerings for doing octaves on guitar using the 1st and 4th finger, or 1st and 3rd fingers.

How are octaves used for in music?
Octaves are used extensively in music to add richness to the sound of a melody or single note. For example, if you pluck the strings of a 12-string guitar, the lower strings are tuned in octaves so that one note makes the sound of two stings together (tuned an octave apart). This is what gives a 12-string guitar such a big sound when you strum it or play a melody line on it. Wes Montgomery was a famous Jazz guitarist who popularized a style of playing solo guitar lines in octaves (see the octave fingerings above), using his thumb to strike both notes together (an octave apart). This helped to add a richness to his melody lines as he played them on guitar.

How are unisons used in music?
The word “unison” is used to describe the interval of two instruments playing exactly the same pitch (not an octave apart, but the exact same note within the same octave). Unisons are often used in music to add fullness and volume to a sound, similar to the way octaves are used. If you’ve ever heard a group of bagpipers and noticed how loud and full it sounds when there are several pipers playing together, what you’re hearing is the whole band playing everything in unison. The low drone and the melody line is often played the same by all the members which creates a huge sound in unison. When recording vocals a common production technique called “doubling” involves recording a singer performing the same exact vocal part multiple times. When those multiple tracks mixed together (often the multiple tracks are panned left/right to give a wide stereo affect) the resulting sound is a much richer version of the same vocal part. This is a great example of the usefulness of a “unison” sound.

## Minor 2nd

The interval of “minor second” is defined as two notes which are a 1/2 step away from each other (e.g. C and Db).  This creates a tense sound.

##### Here is the sound of the minor 2nd interval:
1. minor second example - piano

The minor 2nd interval’s tense sound is often used in soundtracks for horror and thriller movies, usually played in the upper register with violins as shown in this example below:

2. minor second scary strings example

But this interval can also have a beautiful sound as well, when used in the right context.  You will find the minor 2nd interval within chord voicings that use close harmony (all of the notes of a chord in closest proximity to each other, within the same octave) such as this voicing of A minor add9 chord.

3. minor second close voiced chord example

## Major 2nd

The “major second” is defined as two notes which are a full step away from each other (e.g. C and D).  This major 2nd interval has a kind of open sound to it.  .

4. major second piano example

You will also find the Major 2nd used in chords with close voicings, such as this A add9 chord.  The major 2nd adds a kind of “wholesome” vibe.  You hear this kind of use of the major 2nd in film sound tracks as well.

5. major second close voiced strings

## Minor 3rd

#### The “minor third” is defined as two notes that are 1 & 1/2 steps away from each other (e.g. C and Eb).  The minor 3rd makes up one of the key building blocks of triads and chords. We will be talking more about the minor 3rd as we get into a discussion on chords.  Notice that the minor 3rd, has a rather “sad’ sound to it.

6. minor 3rd piano example

## Major 3rd

The “major third” is defined as two notes that are 2 full-steps away from each other. (e.g. C and E).  The major 3rd is also one of the sounds that is used extensively as it makes up one of the key building blocks of triads and chords.   Notice, in comparison to the minor 3rd, the major 3rd has a happy sound to it.

7. major 3rd piano example

When chords are referred to as “Major” or “Minor”, the name comes from the interval of the 3rd within the chord (relative to the root note of the chord). Minor chords contain a minor 3rd interval, and major chords contain a major 3rd interval. I’ll be covering chords in more detail in a a upcoming articles.    The minor and major 3rd intervals are one of the most common ways to harmonize melody lines in music.  Here is one example of the use of major and minor thirds being used as harmony in this recognizable guitar riff from Van Morrison’s “Brown Eyed Girl”.

8. maj 3rd min 3rd example guitar intro

## Perfect 4th

The perfect 4th is defined as two notes that are 2 and 1/2 steps away from each other (e.g. C and F).
Jazz piano players often rely on chord voicings based on use of 4ths to create sophisticated open-sounding chords.

9. perfect 4th piano example

The perfect 4th interval is commonly used for certain types of guitar fills found in classic soul and R&B of the 1960s.  Paul McCartney used this same kind of sound (relying on a basic melody harmonized in perfect 4ths) for the opening guitar riff for his song “Band on The Run”.

10. perfect 4th guitar riff example

## Augmented 4th

The augmented fourth (also called a diminished 5th) is defined as two notes that are 3 whole steps apart from each other.   This interval is also called a tri-tone and is found within dominant 7th chords. In early music this interval was also referred to as the devil’s interval and was strictly avoided by early composers because it was thought to have such a horrible sound. However, in Jazz music especially, this interval forms the basis for some very interesting harmony and chord substitution techniques.  It can also evoke a kind of odd “quirky” quality when used in the right way.

11. augmented 4th example

You can hear a great example of this “quirky” quality of the augmented 4th interval used extensively in the theme from The Simpsons (written by Danny Elfman).

In part II of my article I’ll be covering fifths, sixths, and sevenths. I’ll also include some useful summaries tables.  Happy music making!

# Understanding Musical Harmony: Intro

One of my goals for this site has been to educate people about music itself, to help spread the knowledge that I’ve picked up over the years of learning from various music teachers, other musicians, books I’ve read, and my own experience as a musician and composer.   Early on, all I ever wanted to be was a good guitar player, but one of my first guitar teachers drilled into my head that every musician should understand music itself, not just how to play their instrument.  His argument was that a solid understanding of music theory would empower you to play in almost any style you like, in any key you like, and make sense of what other musicians were doing.  I took his advice to heart and tried to learn as much as I could about music over the years.  Every time I learned a new song or new guitar lick that I liked, I tried to analyze it on musical terms to find out why it worked.  More often than not, there was usually something that pointed back to a topic I’d learned in my music studies that explained why something worked.   I’ve always wanted to pass along those bits of information that helped my understanding so that I may inspire other musicians in the same way as I have been.  I just wasn’t sure how to do this brain dump until now.

# First a disclaimer:

The information I’m providing here is not a substitute for a complete course in music theory. There are plenty of books and resources online to obtain more complete coverage of music theory.  Instead, I will focus my articles on those topics that I use most often songwriting and soloing while leaving out the topics that are more focused on the aspects of music notation and sight reading, which you would cover in any music theory course. As a general emphasis, I’ll focus more on the topics pertaining to an understanding of harmony rather than rhythm and notation.

Music theory can be an intimidating subject to a lot people because the material itself can be a little dry and technical in nature.  I will try to make my explanations more interesting so that it doesn’t read like a text book, but more like a straightforward explanation of how things work (that’s my goal anyway). I’ll also try to explain these concepts by giving lots of musical examples that most people will be familiar with.

When I took music theory courses in college, one of my criticisms was that the musical examples used in the class were often taken from classical works that I wasn’t familiar with. I always wondered why someone didn’t present the material in a more straightforward way using examples found in music that was written in the past century that most people would have heard in popular music, TV, radio, Broadway shows, etc.

# What is Music Theory and Why Study It?

Think of music theory as an explanation of the structure of western music in the same way that science and physics explains the structure and laws of the natural world. By “western music”, I don’t mean music played by guys in cowboy hats and rind-stone suits with names like Hank, Merle, and Buck.  In this context western music refers to music that has its roots in Europe (based on the use of an equally-tempered 12-tone system, or 12 pitches per octave) as compared to music originating in Asia, the Middle East, and India that use completely different tonal system (use of micro tones, etc) that are not normally used in western music.

In the same way that you can appreciate the natural world without having a deep understanding of the laws of physics and biology, your brain is already familiar with the musical structure explained by music theory from exposure to the huge amount of music that you encounter everyday that you’re not even conscious of (music from the web, music used in TV ads, underscore music in film, music that is part of your video games or phone apps) .  Your brain responds to this structure in an emotional way, even though you may not be conscious of the underlying structure of the music itself.  This is an example of the universal language of music.  It’s a language of feeling and emotion.  Music theory only tries to explain these commonly-used structures and set of guidelines (or rules) for what has been used by composers in the past to create various sounds you hear every day in music. Some people tend to understand these structures instinctively, and may not even be aware of it when they write songs. I look to musicians such as Paul McCartney and John Lennon as examples of people who seem to have this innate understanding. Their songs make a lot of sense musically, even though they may not have ever studied music theory or harmony in their development as song writers. However, when you read about Paul McCartney’s upbringing you find that his father played piano at home and was a huge fan of Broadway show music. Paul’s brain was probably infused with a lot of good examples of common chord progressions, song structures, and melodies that he heard so often as a kid, leaving an indelible impact on his musical instincts as a song writer.  In fact you can hear some of this show-music influence in some of his songs such like “When I’m 64” and “Your Mother Should Know”.

# The music you listen to affects your musical instincts

Your ear will often tell you when things work (or not) even if your brain is not aware of the structure, only because your brain is already used to hearing these patterns in other music that you have been exposed to. The lesson here is to listen to great music as often as you can and absorb it! Even if you don’t understand it all, your brain is taking it all in and developing your internal reference points about “what works” in song writing. But don’t stop there, expose your kids to as much great music as often as you can while they are growing up. Expose them to everything: Jazz, Blues, Classic Rock, show tunes, orchestral music, Country, Bluegrass … everything from Abba to Zappa. You never know if you may have a young Paul Simon or Carol King in your midst, absorbing all of that music like a sponge.

# One of the most powerful concepts of music theory is gaining an understanding of harmony

Harmony in this sense refers to the way various notes sound together, not limited only to vocal harmony but any sound source, whether those notes are played on a chordal instrument (such as a piano or guitar) or played by more than one instrument (such as a group of violins, horns, or a guitar and bass playing together). When more than one note is sounding at a time, you have harmony. As I will explain, various notes sounded together will create different harmony depending upon how far apart they are in pitch. Some combination of pitches create pleasant, stable sounds to your ear, and some are tense and unstable, depending on this distance between the notes. Composers use these pleasant (consonance) and tense (dissonance) sounds to create tension and release in their music. This is part of the way emotion is conveyed through music, using this interplay of tension and release. If all music consisted only of pleasant, consonant harmonies and no dissonance, then it would be like watching a movie where there is no conflict, sadness, or struggle, and only happiness from beginning to end.  (Although you may want this effect if you’re writing music to be used for relaxation therapy).  The opposite is also true.   A song with dissonance from beginning to end creates a feeling of uneasiness.   It’s no accident that alarm systems take advantage of dissonant harmony when they design the combination of pitches for an alarm sound.  They want to create a feeling of uneasiness alertness.

Although having a solid understanding of harmony won’t make you a more creative composer, it does provide you with a set of tools to draw from for helping you along the way to refining your inspired ideas into something that is more complete. It also helps you to explore options as you find yourself working through ideas in the songwriting process. It is also an invaluable asset in the arranging and production process as you work through musical parts that need to sound good together, supporting the harmonic structure of the song itself. As an example, check out this version of Elenor Rigby as it likely sounded when Paul McCartney first wrote the basic structure of the tune (although his original version was on piano, and John wrote the lyrics), where you will hear the basic form of the song but nothing more. By contrast, later in the video you hear the full version of the song with the string quartet accompaniment that George Martin brought to it.   You’re hearing George Martin’s skill in applying his understanding of harmony and orchestration to fully realize the potential of the underlying harmony in the song.

The string accompaniment is part of the magic that made this song so amazing.   This is why we want to learn about harmony!