Musical intervals are an important part of training your ears, and understanding what you hear and play. Let’s take a look at exactly what intervals mean for us, and how we can use them.
What are Intervals in Music?
Intervals were first studied by Pythagoras in the 6th Century BC, who discovered the relationship between music and ratio, and explored which ratios were consonant (producing harmony) and which were dissonant. He discovered the ‘purity’ of the perfect fifth – which is commonly used today in power chords and bass lines – and there is even a ‘Pythagorean’ tuning/scale system which consists entirely of intervals of perfect fifths.
There are a few types of interval. Let’s take a look.
Harmonic intervals occur when two notes happen at the same time, working to create harmony.
This is what you’re hearing when you play power chords AKA fifth chords, or when multiple singers are singing the same words and rhythm, at different pitches.
A fifth chord/power chord is also called a perfect fifth harmonic interval, and looks like this on the stave:
Melodic intervals are the spaces between two notes which happen one after the other. If you played your fifth chord as two separate notes, it would be a perfect fifth melodic interval. On the stave, it looks like this:
Now, each of these intervals has different ‘qualities’. If they stick to the notes in the C Major scale, then the intervals will be called either ‘perfect’ – if they’re fourths or fifths – or ‘major’ if they’re seconds, thirds, sixths or sevenths.
Intervals are described as ‘perfect’ when they’re exactly as they should fit in the scale. The only two intervals which can be described as ‘perfect’ are unisons, octaves, fourths, and fifths because they always sound consonant.
If an interval is exactly a unison, it’s called a ‘perfect unison’ and if it’s an exact octave – 12 semitones – it’s called a ‘perfect’ octave. Playing octaves a common device in music, and very common in Jazz – there are even effects pedals which play octaves for you automatically.
If the gap between two notes is precisely 5 semitones (the same distance as the first and fourth note of a major scale), it can be called a perfect fourth. If the gap is seven semitones (like the first and fifth note of a major scale), you have a perfect fifth.
If an interval is one tone / two semitones apart, then it will be called a major second as it’s the same as the first two notes as the major scale.
Similarly, if an interval is 2 tones / 4 semitones apart, it will be called a major third.
If the interval is a total of 9 semitones, it will be a major sixth, in the same way as there are 9 semitones between C and A. If there are 11 semitones in total, it will be a major seventh, like in the case of C-B.
Major intervals all become minor intervals when they are flattened by a semitone.
So, an interval of just 1 semitone is called a minor second. Intervals of 3 semitones are called minor thirds.
If the interval is 8 semitones, you have a minor sixth, and if there are 10 semitones, it’s a minor seventh.
However, there is a big BUT here.
Although it’s true that if you flatten a major interval by a semitone, it becomes a minor interval, the same distance of semitones could also go under a different name.
For example, a distance of 10 semitones may be called a minor seventh, or it may be described as an augmented sixth, depending on which key you’re playing in. These alternative names are called enharmonics.
Diminished intervals occur when you go a semitone under any of the perfect intervals, or a semitone under any of the minor intervals.
For example, a perfect fourth: C – F, would drop from C – E to become a diminished fourth.
A minor third: C – D#, becomes a diminished third when it drops from C – D.
Augmented intervals are the opposite of diminished intervals.
Instead of dropping a semitone from perfect or minor intervals, you raise a semitone from perfect or major intervals.
So, a perfect fifth: C – G becomes an augmented fifth if you lift it to C – G#.
A major second: C – D becomes an augmented second if the D changes to a D’#.
Enharmonics in Musical Intervals
So, as you now know, all of the intervals have 2 names. In the same way, as you can call a D# an Eb, you can call a minor third an augmented second. However, there will always be a correct one to choose.
Which interval is correct will largely depend on which scale you’re playing within. If, for example, you’re playing with the E major scale, you will be correct to describe the interval from E – G# as a major third, rather than a diminished fourth!
However, if you were using F harmonic minor, the same notes would be called E – Ab, making it a diminished fourth interval.
Here’s a table of intervals and their enharmonics:
|Number Of Semitones||Name||Enharmonic(s)|
|2||Major Second||Diminished Third|
|3||Minor Third||Augmented Second|
|4||Major Third||Diminished Fourth|
|5||Perfect Fourth||Augmented Third|
|6||Diminished Fifth||Augmented Fourth / Tritone|
|7||Perfect Fifth||Diminished Sixth|
|8||Minor Sixth||Augmented Fifth|
|9||Major Sixth||Diminished Seventh|
|10||Minor Seventh||Augmented Sixth|
Ear Training with Intervals
Learning to recognize intervals by ear is a large part of most musical training. Luckily, there are some really easy ways to do this.
All intervals have some well-known songs which have used them in their hooks, so once you know which hook is which interval, they become easy to recognize.
Here are some tunes that can help you to train your ears:
Minor Second – Jaws Theme Tune
Major Second – Happy Birthday
Minor Third – Seven Nation Army – The White Stripes
Major Third – Oh When The Saints
Perfect Fourth – We Wish You A Merry Christmas
*Tritone – The Simpsons Theme Tune
Perfect Fifth – Twinkle Twinkle Little Star
Minor Sixth – The Entertainer
Major Sixth – Hush Little Baby
Minor Seventh – The Winner Takes It All – Abba
Major Seventh – Take Me On – Aha
Octave – Singing In The Rain
Minor Second – Fur Elise – Beethoven
Major Second – Yesterday – The Beatles
Minor Third – Hey Jude – The Beatles
Major Third – Swing Low Sweet Chariot
Perfect Fourth – Eine Kleine Nachtmusik – Mozart
Tritone – The Beautiful People – Marilyn Manson
Perfect Fifth – Flintstones Theme Tune
Minor Sixth – Hey Joe Bass Line Riff – Jimi Hendrix
Major Sixth – Man In The Mirror Chorus – Michael Jackson
Minor Seventh – Watermelon Man
Major Seventh – I Love You – Cole Porter
Octave – Willow Weep For Me
Now, this makes training your ears to recognize intervals easy.
You and a fellow musician could test each other, by playing some of these intervals and seeing if you can recognize them based on their famous uses.
Application of Intervals
If you’re reading this as a guitarist or bass player, and still wondering how it might apply to you and your playing, here are some ways that you can make use of intervals.
Basslines are often written using perfect fourths, perfect fifths, and octaves. Now that you know what these are, and understand that they always sound consonant, you can apply them to your own playing.
Luckily, on the bass guitar, there is a really easy way to remember how to find your fourth and your fifth.
To find the perfect fourth of the note you’re playing, simply jump down a string, remaining on the same fret. How easy is that?
To find the perfect fifth, you jump down a string like you were finding the fourth, then move across two frets, i.e. a tone. Makes sense, doesn’t it?
Now, instead of nervously sticking to the root notes as you’re following chords, you can have some fun adding some perfect fourths and perfect fifths to the mix. We promise it will sound good.
Consonance is also an essential part of pleasing vocal harmonies, so now you know which intervals work well and which ones work not-so-well, you can experiment with these using your own and others’ voices.
As well as singing the melody line, try adding some perfect fourths, perfect fifths or some major thirds in there. You might prefer minor thirds; it depends on the song! If you use the aid of a piano or other reliable instrument to guide you, you’ll be singing harmonies in tune in no time, thanks to your awareness of intervals.
Sometimes, you create a cool riff, and repeat it lots and lots throughout the song… and then it gets a bit boring. It starts itching for alteration. Using appropriate intervals is your key out of limiting repetition.
Instead of going, for example, C, C, Eb, C, yet another time, you could try: C, C, Bb, Octave-C – swapping the Eb for its perfect fifth and making your resolving C an octave higher. These kinds of tricks can make your playing less predictable and more fun.
Music theory like this can make some people run and hide, but it really is just numbers and very simple maths, offering an explanation for the pleasant sounds you hear. Developing an understanding of the distances between the notes (or ratios in Pythagorean thinking), and what makes them work the way they do, can make you more insightful as you listen to music and more interesting as a musician and songwriter.
You can use well-known songs (as seen in the table above) to train your ears to recognize different intervals, and as a result of this become informed as to what is going on when learning others’ songs or when putting together your own melodies or harmonies.
Now you have some understanding of the theory behind intervals, it’s time to experiment with perfect fourths, perfect fifths and whichever other ones you want to try!
Allowing interval qualities to enter your consciousness with both liven up your playing and sharpen your ears. It’s a sure way to become a better musician and a faster learner.