The Mixolydian Mode in Music
What is the Mixolydian mode?
The Mixolydian mode is a type of diatonic scale dating from the Middle Ages. It was originally one of the church modes that were modelled on a system used in Ancient Greece and devised for the purpose of classifying pre-existing music of Gregorian chant. You can learn more about its history further on in the article.
What defines this scale, as with all scales, is the unique interval arrangement between the notes. Before sharps and flats were introduced in music, the Mixolydian mode was based on G and consisted of the notes: G A B C D E & F.
Centuries later, we had a full complement of sharps and flats that had gradually been introduced into music notation, so the Mixolydian mode could then be transposed and based on any note. The sharps or flats are necessary to ensure that the correct spacing or intervals between successive notes is maintained.
The chart below shows the Mixolydian mode laid out as a scale starting on various notes. The intervals between the notes are always exactly the same pattern of WHOLE TONES (T) and SEMITONES (S) as shown in the chart. Tones and semitones are also known in the US as WHOLE STEPS (W) and HALF STEPS (H).
The distinctive Mixolydian melodic character
Look at any of the Mixolydian scales in the above chart. If you're familiar with major scales, you'll notice that each one looks very similar to the major scale starting on the same note, but with one very important difference. The seventh note is one semitone lower than in the corresponding major scale. Compare G major with G Mixolydian.
G major - G A B C D E F# G
G Mixolydian - G A B C D E F G
In the G major scale, the seventh note is F#. It's only a semitone lower than the tonic note G. That semitone gap gives the major scale a strong 'leading note' quality which is very evident whenever we hear music in the key of G major (or any major key, in fact).
G Mixolydian's seventh note, F natural, by contrast, is a whole tone lower than the tonic note G, so it lacks that distinctive leading note quality. It still has an overall 'major' type quality, but that important difference of the seventh note changes its character significantly. Mixolydian music is like major key music in character but with something of a minor key quality too. It's often thought of as having something of a bluesy or folk character.
The Hills o' Gallowa' in the video below is a Scottish folk melody in the Mixolydian mode. As you can hear, the tonal centre is G. (Listen to how finished it sounds on the last note, G.) The melody has a major feel to it, but the presence of the note, F natural' rather than F sharp gives it a distinctive flavour which is uniquely Mixolydian.
The Hills o' Gallowa' - Mixolydian mode melody
The table below shows all the possible triads that can be formed by combining the notes of the mode, but most Mixolydian modal music, like most modal music in general, tends to use simple harmonies in the form of repeating sequences (known as modal vamps) consisting of two or three different chords at most,
Chords of the key of G major and the mode G Mixolydian compared
G A B C D E F G
G A B C D E F# G
G Major (G B D)
G major (G B D)
A minor (A C E)
A minor (A C E)
B diminished (B D F)
B minor (B D F#)
C Major (C E G)
C major (C E G)
D minor (D F A)
D major (D F# A)
E minor (E G B)
E minor (E G B)
F major (F A C)
F# diminished (F# A C)
Mixolydian modal vamps
Here are a couple of common Mixolydian modal vamps that can be improvised over by using the appropriate Mixolydian mode.
G - F - C - G ( Use G Mixolydian - G A B C D E F G)
D - Am7 - C - D (Use D Mixolydian - D E F# G A B C D)
Mixolydian modal music
The Mixolydian mode has featured in lots of music from as far back as medieval Gregorian chant up to modern times (but far less commonly). Its unique series of tones and semitones gives the music a distinctive 'Mixolydian' flavour or character in exactly the same way that major and minor scales give rise to major and minor key music each with its distinctive character that we recognise as major or minor sounding. The Scottish traditional folk melody in the video demonstrates that flavour effectively.
Modal Music of the Medieval and Renaissance Periods
Western music was modal during these periods. (The major-minor key system hadn't yet arrived). As one of the principal church modes, the Mixolydian mode (and its now obsolete partner, the Hypomixolydian mode) was commonly used as the basis for music composed by Church appointed composers, such as Leonin and Perotin as well as by secular composers, such as Adam de la Halle.
Modal Folk music
A lot of folk music (especially Celtic influenced folk music) of Britain, Ireland, and Brittany in France, as well as Canada, the USA and elsewhere, features the Mixolydian mode as its note source. The Irish traditional song "She moved through the fair" is another famous example of a song in the Mixolydian mode.
The emergence of the major-minor key system of composition in the late 17th century led to the eventual end of the modal style of composition. Most composers of the Baroque and Classical periods, such as Bach Haydn and Mozart, largely (but not completely) ignored the modes in favour of the major-minor key system. Later composers of the 19th and 20th centuries, such as Debussy, Sibelius, Vaughan Williams, Rimsky Korsakoff and others sometimes revived them to take advantage of their distinctive flavours in their compositions. Debussy's composition, "The Sunken Cathedral" features the Mixolydian mode as does Leonard Bernstein's Cuban styled 'danzon' "Fancy free".
Jazz composers in the late 1950s, such as Miles Davis, introduced modes (including the Mixolydian mode) as a principal element in their compositions in the style of jazz now known as modal jazz. The Miles Davis composition "All Blues" is in the Mixolydian mode with some chromatic embellishments in the harmony,
Modes in Popular music
Mixolydian-based folk music had a strong influence on rock and popular music of the 60s and 70s and it's not unusual to hear music from that time that was strongly influenced by the Mixolydian mode.
Examples of Mixolydian, or Mixolydian influenced, songs include:
Norwegian Wood (verses) - The Beatles
Hey Jude (end section) - The Beatles
If I were a carpenter - Tim Hardin
I'm so glad - Cream
Sympathy for the Devil - The Rolling Stones
The Gates of Eden - Bob Dylan
A Brief History of the Mixolydian Mode
The Mixolydian mode started life as a type of scale devised (along with others) by medieval European monks . The name was borrowed from the ancient Greek note classification system (tonoi) in the mistaken belief that it was identical to the original Greek scale of that name. Later and better informed research into the ancient Greek system showed that, apart from the name, the medieval Mixolydian mode has little in common with the original (and long since obsolete) ancient Greek Mixolydian scale.
Each of the original so-called authentic modes had what's termed a plagal version. These consisted of the same notes but starting four notes lower. The Mixolydian mode's plagal partner was called the Hypomixolydian mode. Both were based on the same note, G, as principal note (called the finalus or final) but the Hypomixolydian mode started on the D below the low G of the authentic Mixolydian mode. Its purpose was to extend the pitch range downwards, while still keeping G as the final but in the middle of the the range rather than as the lowest note. Early church-based modal music had strict rules about pitch range. The Mixolydian mode in later usage had no such pitch range restrictions, so the Hypomixolydian mode and all the other plagal modes became redundant and obsolete.
The Mixolydian mode (along with other 'church modes') was an important scale for composers for around a thousand years until the modal system of composition fell into decline and gave way to today's major-minor key system. Tonality and functional harmony were on the rise and the new major-minor system (which dates back to the latter part of the 17th century) was better equipped to establish strong tonal centres and more complex key relationships.
The 5th 'mode' of the Major Scale
You may have noticed that the G Mixolydian mode shown at the top has exactly the same notes as the scale of C major, but starting on the 5th note, G, instead of C. Because of the dominance of major key music nowadays, it has become popular to think of the Mixolydian mode in terms of the major scale but starting from the 5th note. Or rather, it has become popular to label the 5th 'rotation' of C major (C major starting from G) as a 'mode' and call it G Mixolydian. This is a different (and technically incorrect) use of the word mode but has gained popularity and is now an acceptable (or at least tolerated) usage.
There are some (limited) advantages in thinking that way, such as using the names as memory aids for targetting chord tones efficiently when improvising with memorised scale shapes to best match the chords of the key as they appear. Some guitarists like to think this way due to the string-fret arrangement of guitar fretboards producing easily memorised and consistent fingering patterns. But don't fall into the trap of thinking that the label Mixolydian in this case is referring to Mixolydian modal music - it's just a rotation of the major scale that may be used when the current chord is the one built on the 5th scale degree - (G or G7 in the case of the key of C major).
For example, if you improvise a G Mixolydian melody over a chord progression in the key of C major, the Mixolydian modal flavour will be lost because the tonal centre that you hear (whether consciously or unconsciously) is C, not G (the true tonal centre of G Mixolydian music). The chords are making C, not G, the tonal centre. You'll just hear the distinctive major quality of C major, not the subtly different Mixolydian quality of G Mixolydian. The notes of G Mixolydian will still fit perfectly (especially over a G7th chord) because they're exactly the same notes as the C major scale, but the effect and quality will be C major, not G Mixolydian, because the chords are reinforcing the song's key (C) and mode (major also called Ionian). It may have a strong dominant 7th quality too if G7 is played a lot, but it won't have a true Mixolydian quality.
You would need to make those notes relate to G as their tonal centre for the Mixolydian sound to emerge. So, you'd need a new chord progression with G as its tonal centre, (such as a modal vamp like G F C G), with added emphasis on the G to ensure it becomes the new tonic.
Alternatively, you could keep C as the tonal centre by using C Mixolydian and changing the chords to fit the C Mixolydian mode instead of G Mixolydian. C Mixolydian is C D E F G A Bb C (like C major but with the 7th flattened - exactly as explained at the beginning when we compared G Mixolydian with G major). Hey Jude is a great example of a song that changes mode: from Major to Mixolydian. The song is in F major right up until the start of the long 'outro' section where it changes to an F Mixolydian modal vamp (F -Eb - Bb - F).
Analogy with C major and A minor
It's exactly the same if you improvise with the scale of A natural minor over a chord progression in the key of C major. The over-riding quality will still be major and not minor as long as the chords are making sure that the key (and tonal centre) is always C major. Again, the notes will fit because A natural minor (like G Mixolydian) has exactly the same notes as C major - just starting from a different place. But the end result will be heard as C major, not A minor, unless the A minor chord is sustained long enough to be heard as a new tonal centre by default.
Historical facts in this article were checked with Medieval.org, a scholarly and authorative information site on music of the Medieval Period.