Music theory can be a very daunting subject to tackle for guitarists. Intervals are a way of breaking down the fretboard into easy octaves. Today, we show you the easiest way to learn them!
Intervals: The Fretboard In Numbers
If you have spent any time learning music theory or scales, then you have probably ran into Intervals. When I first started taking lessons, I learned about Intervals in the most dry and boring way possible. In fact, just trying to do it by rote memory made it harder for me to learn. But in reality, the concept is pretty easy to grasp once you see it. It is even easier when you are putting the information to use “hands on”.
What Are Intervals In Music?
Intervals are the essential building blocks of scales, chords, harmonies, and melodies. Intervals are the measurement between two pitches, ascending or descending. On the guitar, each fret can be measured as an interval! With guitar scales, they are pitches referred to as numbers between a Root Note and an Octave.
So that seems pretty easy right? Each fret is an interval, and it will have a different number depending on the root note. With guitar, we use intervals often with scales. They are really just the steps you take to get from the root note that you start at, to get to the next octave. Intervals honestly cannot be more straight forward than with a guitar or piano, so you actually have the advantage!
Things change ever so slightly when we start talking about chord structures. Adding certain Interval Numbers into a chord can change the chord’s quality completely! Sometimes, just changing one note in a chord can change the entire sound and therefore, the Quality. We are going to tackle Qualities, and Intervals today at the same time since they go hand in hand. But we are going to do this the EASY way.
So let’s dive right in to what Intervals are on the fretboard, as well as how they work. If you have already studied scales, this may seem pretty familiar! As with all of our lessons, go ahead and grab your guitar because this is definitely a hands on experience.
Basic Music Theory: Quality/Character
In music, Intervals are the space between two sounds. Each fret on your guitar is an interval, since each fret changes the pitch of the fretted note. With guitar, it is easier to think of these as whole tones and semitones. In Western music theory, we look at intervals in a few different ways. The one that you have probably seen before is the numbered system. Really we can break it down to just two different categories: Quality and Numbered Intervals
Quality in basic music theory is going to pertain to scales and chords alike, and the Quality is best thought of as a mood or “sound”. For example, many people would describe the Major Scale as “happy” or “joyful”. Likewise, some people associate Minor Scales and chords with “sadness” or “ a dramatic feeling”. Augmented and Diminished Qualities can sound “unfinished” or draw the listener in, by adding a new distinct sound to a chord or scale.
These “Qualities” are important when adding a note into a scale or chord, and certain added notes can change a scale or chord from Major to Minor. In fact, just one note can be the difference! We will get into this in greater detail. But for now, just remember those quality names. The easiest distinction for you to hear in music is the difference between Major and Minor. But Augmented and Diminished are just as important, but less used.
These are also known as diatonic numbers in basic music theory. This is where guitar might actually be an easier instrument to learn music theory with, because of the way the fretboard is laid out. This is because numbered intervals are pretty straight forward when you are looking at the fretboard. Each scale that you learn is made up of these intervallic numbers. For reference, we can take a look at the Interval numbers on a guitar fretboard:
This is a numbered Interval chart in the Key of F. The notes marked as “R” are the Root Note, which is F. Every R that you see, is an octave of the Root Note, since the Root Note always repeats in these same increments, with the one at the bottom being the lowest note. Take your guitar right now and hit an open string, then hit the 12th fret. That’s an Octave, the same note but higher in pitch! The official definition is:
Octave: A series of eight notes occupying the interval between (and including) two notes, one having twice or half the frequency of vibration of the other.
These series of 8 notes all have a Interval Number, and that is where we get into the real function of Intervals. Each step/fret/note between your Root Note and the octave has a different number, but the Root Note is always “1“. These numbers are important when looking at scales, because it will help you understand what makes the Quality of a scale. Adding sharps and flats will change the Quality of a scale or chord. The C Major Scale for example, has no sharps or flats. The number system is easy to remember:
- Root Note
- Flat Second (Semitone or Half Step)
- Second (Full Step)
- Flat Third
- Perfect 4th (Neither Flat Nor Whole)
- Flat Fifth
- Perfect Fifth
- Flat Sixth
- Flat Seventh
- Root Note (Octave, Perfect)
You may have noticed that some of these are called Perfect and some are Flat/Major. The Root Note/Octave is called the Unison, and it is does not have a Flat or Major version. The same goes for the Fourth and the Fifth. Perfect intervals are always going to be natural to natural, sharp to sharp, and flat to flat. This is because there is no “B Sharp”, the next note is C. Just like there is no “E Sharp” since the next note is F.
Outside of the Perfect Intervals, we have the Flats and Sharps. Flats and Sharps are also known as “accidentals” because they cause a bit of harmonic discourse by raising or lowering the pitch of the note before it. They are common today, so accidentals is kind of an outdated term. But it is still used in academic music theory studies.
Numbered intervals are absolutely essential to understand when it comes to building scales and chords. If you compare the names with the picture example above, you can see how these work. The picture shows you the intervals in the key of F, but this is the same no matter what the root note is. For example, move one fret up from the Root Note anywhere on the fretboard, and you are on the Flat Second, no matter what key you are in. They always go in order.
Looking at the fretboard as a series of numbered Intervals can take some getting used to, just like learning the notes of the fretboard. I know, it seems like more work since you already learned the notes and NOW they have numbers too! But as you dive into more basic music theory, it will start to become almost second nature when you look at scales. You will start to hear the subtle difference adding a Perfect Fourth, for instance, makes when building chords and scales.
Check out The Major Scale and The Minor Scale to see how Intervals play a huge part in the way a scale can sound! Both of these lessons will show you how the Intervals change the sound of a scale. In fact, maybe you should leave those lesson windows open as we move on to chords, for reference.
Basic Music Theory: Intervals And Chords
So we know how the Intervals work individually in a scale pattern, and how they can change the whole sound by adding just one note in some cases. The Melodic Minor Scale is almost a Major Scale when we look at it on paper. But that Flat Third in the Melodic Minor Scale keeps the tension going, and makes the scale remain Minor, albeit a little weird.
This can be applied to chords as well, and it is easy to think of chords as “Scales played all at the same time”. Likewise, you can think of scales as “Chords played by individual note”. Does that sound confusing? It might at first, but let’s take a look at something we are all familiar with: The G Power Chord.
If we take a look at the G power chord, we can really break down why it works using Intervals. Power Chords are often called “Power Fifth” chords because they feature the same set of notes and Intervals no matter what Root Note you start with. Power Chords are all made up of:
- Root Note (First)
No matter where you play a Power Chord, up and down the neck, it is going to be made up of those three Intervals. But a Power Chord by itself is “neutral” by nature, technically. It is neither Major or Minor in this simple form. So what do we add to turn a G Power Chord into a Minor? Well if you check out the Natural Minor Scale, you will definitely get your answer. We need at least one Flat, don’t we?
What we added to make the G Power Chord into a Minor Chord, is the Flat Seventh, and Flat Third. We keep the Root Note, Fifth, and Octave that we had before, but adding these two Intervals from the Minor Scale changes the whole sound. It also changes the scale that you would play over it! Now, the Natural Minor Scale would be the go-to answer to write a solo or melody.
Now I didn’t just pull those notes out of thin air. It wasn’t some kind of magic or secret knowledge. The Intervals of the G Minor Scale told me everything I needed to know, to make the Power Chord into a Minor Chord. Let’s take a look at the Natural Minor Scale In the Key of G. The answers to how I made the chord are right there!
I think it is pretty apparent now, how we turned the simple Power Chord into a Minor Chord. The Flat Seventh and Flat Third are right there. Now the Flat Sixth is also there, but that would have changed the chord to something else, and we will get to that. But how did I know which Intervals to pick? Seems like there are a lot in that scale!
To make a Major Chord, you will always use the Root, Third and The Fifth. But to make a Minor Chord, you will always use the Root, Flat Third, and The Fifth. The rest of the notes that we added in the G Minor Power Chord were either repeats, or the Flat Seventh, in this case the Seventh was F. Where did I get the Flat Seventh (F Note)? I have an easy answer for that!
The Flat Third in the G Minor Power Chord is a Bb/A# note. The Perfect Fourth for Bb is F. Perfect Fourths work together Harmonically! Play F on the first fret of the low E string on your guitar, and then play first fret on the A string (Bb). Perfect Fourths form a chord on their own, just like Perfect Fifths do as Power Chords! This works the same way in Major keys, except with the Major Third and Major Sevenths!
Try this out with some other Power Chords with your guitar. Not only will your ear be able to pick up the difference between Major and Minor qualities, it will soon become second nature to know which intervals you need to add to make any chord into a Major or Minor! You can also take a Minor Chord, and rearrange it to be Major. Try it out!
Intervals: Augmented Chords
An Augmented Chord is a Major Triad with a Sharp Fifth/Flat Sixth (They are the same thing). You often may see them written as C+, or maybe C+7. We say these out loud as “C add Nine”. Augmented chords can sound a little dissonant, and add some serious tension to a chord progression. Let’s look at the most basic form of an Augmented Chord in the Key of C:
So that Flat Sixth that we added makes everything sound a little…wrong right? That’s because it is supposed to sound a little “off”. The Flat Sixth takes the place of the Major Fifth that usually sounds so pleasant in an open C chord. So where do we get the C+7 chords? The answer is again in the Intervals! All we need to do is add a Major Seventh to the Augmented Triad to get C+7. That Major Seventh is an open B note.
Sounds a little creepy right? that is because these Augmented Chords are supposed to cause a bit of unease and induce anxiety in the listener. Think about the fist notes in the progression of the song “Hurt” by Nine Inch Nails. It causes things to sound “off” or “wrong” and can be really effective as a changeup in a song. These Augmented Interval positions can be really useful when crafting a song or solo. Try to find your own Augmented Triad (three notes) on your own, using a different Root Note!
A Diminished chord is a triad built from the Root Note, Flat Third, and a Diminished/Flat Fifth when it comes to Intervals. These chords can be super useful when you are trying to find a way to create some dramatic moments in a song. They sound dark, with a little bit of dissonance thrown in to sound creepy in a “sometimes” more musical way than Augmented Chords.
To make a C Diminished Chord, we are going to have to go up a little higher on the fretboard, since it will be easier for you to hear the sheer creepiness up high. Plus I think Diminished Chords sound downright scary when they are higher up! The formula for C Diminished is: Root, Flat Third, and Flat Fifth: C, Eb, Gb.
Now that is a creepy sound, isn’t it? You hear the sound of Diminished Scales and Chords a lot in all types of music. You may have heard a Diminished Chord before, and mistaken it for a Minor Chord. But the sound is definitely different. If you add a Flat Seventh, things get even MORE creepy. You actually hear this as a Scale often in genres like Black Metal, and for a really good reason! Try playing this one:
When I think of Diminished Chords, I can see why sometimes they are mistaken for Minor Chords and Scales. The “dark” factor is definitely there, and those notes and Intervals are similar to the Minor Scale too. So it can be easy to get them confused. Knowing what a Diminished Interval Structure is composed of, can you find your own now, using a different Root note than C? Try finding just the Triad first, the three simple notes.
Intervals: Wrapping Up…
At the beginning of the article, I talked about my first teacher and how they just gave me a sheet of paper with numbers on it to learn Intervals. Sitting there just trying to learn the number degrees between my scales was boring. I think putting them in action like this, is a way easier way to get a grasp on how these numbers work in a musical way.
I mean, go back and play the Natural Minor Scale that we talked about. You can hear the tension between the notes, and how Flats effect the whole scale. But more importantly, you know the different numbered positions now of the most important scales, that are the building blocks for all music. Intervals help you understand the fretboard a little more, and it may even make the fretboard seem smaller now!
Think about it, there are only 8 degrees of separation between any Root Note and its Octave. This makes scales seem a little less mysterious, at least it did for me. The same patterns repeat over and over, no matter where you are on the neck. Now, you have the tools to understand just how close that patterns are to one another!
Christoper HortonChristopher has been playing guitar and piano for 27 years. He has been active in the professional music industry for over two decades. He has toured for years with several bands and music projects. He worked in LA as a studio musician and engineer working with bands like IAMSOUND, Baroness, Kylesa, Black Tusk, Reflux, and Tripping Daisy. In between giving private lessons, he is recording a solo album for 2022-2023. Christopher plays Schecter guitars, BOSS amplifiers, and uses STL Tones in the studio.
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