The Key of One Part 5: Understanding the Modes

To most beginning students, the word “modes” sound intimidating—not unlike the word “theory.” But much like we found our basic theory to be much simpler than we thought, the same applies to the modes.

To most beginning students, the word “modes” sound intimidating—not unlike the word “theory.” But much like we found our basic theory to be much simpler than we thought, the same applies to the modes.

The basic seven modes—Ionian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, and Locrian—come from the major scale formula. They’re a byproduct of playing the notes of any given major scale starting on any number other than the 1. So if you were in that particular note’s key, you would be playing a mode. In the grand tradition of giving things multiple names to confuse us, two of the modes simply are the major and minor scales: the Ionian and Aeolian, respectively. That leaves five modes and four of them are only one note different than the formula for a major or minor scale. Here’s the breakdown:

  • Dorian: minor scale with a major sixth.
  • Phrygian: minor scale with a b2.
  • Lydian: major scale with a #4.
  • Mixolydian: major scale with a minor seventh.

The final mode, Locrian, differs from a minor scale by just two notes: the b2 and the b5. All told, the modes “justify” using a b2, b5,and major sixth in a minor scale and the #4 and minor seventh in a major scale. If you use these single substitutions every time, you’re playing modally. When you look at the modes this way, they’re much simpler to conceptualize and use in your playing. Your comfort with the sounds of the numbers will help infuse your note choices with intention as you play, because in the end, every note is somehow justifiable by context. Like spoken or written language, musical language is meant to be adaptive and flexible.

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In order to practice the modes, simply make the above substitutions in every key. Since C major gives you the modes right on the white keys, it’s the easiest place to start playing modally. To play Dorian, play a D bass note (I like to play an octave to reinforce that tonally) in your left hand and play up the white keys with your right, starting on D. It’s the D minor scale but notice the sound of the major sixth and the difference it makes. For Phrygian, move to an E octave in the left hand and play up the white keys in the right. Listen to the way the b2 sounds in the E minor scale. An F octave in the left hand will turn the white keys into the Lydian mode and suddenly your F major scale has a #4 in it. Move up to a G octave in the left hand and the white keys give you the Mixolydian mode: a G major scale but with a minor seventh, which sounds kind of bluesy.

We can skip Aeolian for now, as we’re hopefully already familiar with the minor scale. Lastly the Locrian mode can be heard with a B octave in the left hand and the white notes in the right. You can hear the b2 and b5 and they sound distinct in the B minor scale. Don’t just learn what we’ve gone over here; learn the substitutions based on transposing to all 12 keys.

Other modes and scales were invented along the way, and they’re also closely related to our major/minor scale formula. Plus, they also justify note substitutions. Two common examples are the harmonic minor and harmonic major scales. The harmonic minor simply uses a major seventh in a minor scale, while the harmonic major uses a minor sixth in a major scale. Much like we saw with the basic modes, if you play those note substitutions every time, you’ll be playing in those alternate scales. However, you can also use those justified substitutions on demand to color your melodies while writing or improvising.

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There’s one note that’s justified for both the major and minor scales: the b5 (or #4) between 4 and 5. That note is not used in the major or minor scale, but it is used in the blues scale, and is in fact the main reason the blues scale fits over major and minor chord progressions alike. Much of its justification comes from its appearance in the Lydian and Locrian modes. Remember, every note can be justified in one way or another, and improvisation is just creating that justifying context in real time.

Practice these modes while consciously speaking or singing the numbers of the notes out loud to reaffirm them in your mind. You can also play modally and then switch back from the substitution to hear the difference between the mode and the scale it’s close to. Your understanding of this is important, as is the ability of your fingers to move dexterously on the keys. But it’s your ears’ ability to “hear those numbers” that will help your brain learn to interpret and apply them. 

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Robbie Gennet is a touring keyboardist, guitarist, longtime Keyboard contributor, and educator at Musicians’ Institute in Hollywood, California. His book, The Key of One (Alfred Music) outlines a thorough method for understanding music without learning traditional notation. You can get it at, and take private lessons from Robbie at

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