• Implications of The Leading Note in Modality

    in Piano,Scales,Theory

    leading note image

    In this lesson, we’ll about talk what the leading note in modality is and interesting ideas derived from it.

    Recall that there are twelve pitch classes (notes):
    leading note twelve pitch classes

    Back in the controversial medieval ages (when music was considered a sacrifice [unto God]), the white notes were viewed as holy while the black notes were considered devilish. The present day keys (G major, B major, etc) weren’t in use then.

    It was all about modes. Modes were formed from a stepwise progression on any holy note to its octave. Each mode has its characteristic name.

    C-C is the Ionian Mode:
    leading note C ionian mode

    D-D Dorian:

    E-E Phrygian:

    F-F Lydian:

    G-G Mixolydian

    A-A Aeolian

    B-B Locrian

     

    Modes are different in concept and application. However, there are similarities between modes and present day scales. The Aeolian and Ionian modes are equivalent to the present day minor and major scales.

    Pure Minor Scale / Aeolian Mode

    Pure Major Scale / Ionian Mode

    Leading Note Property

    If the interval between the seventh and first note of a mode is a semitone progression, the seventh tone is said to be a leading note or leading tone. Scales that had the leading note property were considered more interesting because the seventh tone was just a semitone (half step) away.

    What is the leading note property?

    The leading note property is the quality that a scale/mode possesses if the distance between the 7th and 1st degrees is a semitone (or half step).

    If we go through the distances between the 7th and the 1st notes in each of the seven modes, we will see that only two modes have the leading note property – the Ionian and the Lydian modes.

    The Ionian mode has the leading note property between the between B and C (7th and 1st):

    *There are no notes between B and C. Thus, these two notes are a semitone or half step apart.

    The Lydian mode has the leading note property between the E and F (7th and 1st)

    *There are no notes between E and F. Thus, these two notes are a semitone or half step apart.

    Other modes don’t have the leading note property as you’ll notice the 7th to the 8th degree are a whole tone apart (i.e. – there is a note in between).

    Dorian – in between C and D is a whole tone:

    Phyrgian – in between D and E is a whole tone:

    Mixolydian – in between F and G is a whole tone:

    Aeolian – in between G and A is a whole tone:

    Locrian – in between A and B is a whole tone:

    There is a stronger affinity between the 7th and 1st tones of the modes that have the leading note property.

    Musicians that lived in the generation of modes often desired to have this property in other modalities. In order to replicate this feeling in other modes that lacked this property, their 7th tones were raised. For example, if the 7th tone (C) of the dorian mode (D E F G A B C D) is raised (to C), it will yield a variety of the same dorian mode – with the leading note property:

    The variety created now has that coveted leading note property. C has more of an affinity for D than C does. However, beyond the leading note property created, there are other implications. In this article, we’ll cover such implications. You’ll be thrilled to know these implications when we are done.

    Implication #1 – It Yields Modal Varieties That Are Similar To Scales

    Modes existed before scales. When the 7th note of a mode was raised to create the leading note property, it led to a variety of the same mode. We see these varieties and their relationship in present day scales.

    Dorian Mode

    Raising the 7th note (C) of the dorian mode to Cwill yield:

    This variety of D Dorian is related to the present day melodic minor scale.

    New Perspective: You can associate the melodic minor scale with a Dorian mode with a raised 7th.

    Therefore, the present day E Dorian mode (which is, in actuality, the D major scale from “E” to “E”):

    …can also yield E melodic minor if we raise its seventh degree (D to D).

    The melodic minor scale is a variety of the pure minor scale that is used in traditional practice when the pure minor scale is unsuitable because of its lack of the leading note property. We’ll explore the shortcomings of the pure minor scale in another article.

    Mixolydian Mode

    Raising the 7th note (F) of the myxolydian mode to Fwill yield:

    This variety of G mixolydian is related to the present day major scale (and also the Ionian mode).

    New Perspective: You can associate the major scale with a mixolydian mode with a raised 7th.

    Therefore, the A mixolydian mode:

    …can also yield the A major scale if we raise its seventh degree (G to G):

    Aeolian Mode

    Raising the 7th note (G) of the aeolian mode to Gwill yield:

    This variety of the A aeolian is related to the present day harmonic minor scale.

    New Perspective: You can associate the harmonic minor scale with an aeolian mode with a raised 7th.

    Therefore, F Aeolian mode:

    …can also yield the F harmonic minor scale if we raise its seventh degree (E to E):

    The leading note property can be used on these modes because the interval between the 7th and the 2nd degrees in each mode is consonant.

    Dorian (C-E) – minor third:

    Mixolydian (F-A) – minor third:

    Aeolian (G-B) – minor third:

     

    Implication #2 – The Leading Note Forms A Chromatic Dissonant Interval

    Certain modes, when raised, yield chromatic dissonant intervals. In traditional practice, chromatic dissonant intervals are forbidden because of their extreme dissonance. There are two modes that belong to this category – Phrygian and Locrian Modes.

    In these modes, the melodic progression between the 1st and 2nd degrees is a semitone.

    Phrygian Mode: Between E (the 1st note) and F (the 2nd note) is a semitone or half step:

    Locrian Mode: Between B (the 1st note) and C (the 2nd note) is a semitone or half step:

    This is a remarkable difference between these modes and the modes we considered earlier. Between the 7th and 2nd degrees of these modes, the interval formed is a minor third.

    Phrygian (D-F) – minor third:

    Locrian (A-C) – minor third:

    Therefore, even though they don’t have the leading note property, they are better off without it. However, if we go ahead and raise the seventh degrees of these modes, we’ll create the forbidden interval. Let me show you…

    Phrygian Mode

    Raising the 7th note (D) of the phrygian mode to Dwill yield:

    This variety of E phrygian is NOT related to ANY of the present day traditional scales. This is because of the FORBIDDEN interval between its 7th and 2nd notes.

    The 7th note is D and the 2nd note is F:

    The interval above is a diminished 3rd. It is a chromatic dissonant interval and is FORBIDDEN in traditional practice.

    Locrian Mode

    The same thing is obtainable in the locrian mode.

    Raising the 7th note (A) of the locrian mode to Awill yield:

    This variety of B locrian is NOT related to ANY the present day traditional scale. This is because of the FORBIDDEN interval between its 7th and 2nd notes.

    The 7th note is A and the 2nd note is C:

    The interval above is a diminished 3rd. It is a chromatic dissonant interval and is also FORBIDDEN in traditional practice.

    Now, do you agree with me that the 7th tone of the phrygian and locrian modes are not to be raised?

    Final Words

    It is my hope that you’ve gathered a lot of knowledge from this lesson.

    In closing, I want to sum up all that we covered in this post as follows:

    1. There are two modes that come naturally with the leading note property.
    2. Feel free to replicate the leading note property on other modes like the dorian, myxolydian and aeolian. However, you must understand the relationship between the varieties you will come up with and present day scales.
    3. The leading note property is forbidden on the phrygian and lydian modes. This is because of the diminished third that will be formed between the 7th and 2nd tones. If you insist, you will not derive any variety that is related to present day scales.

    In another post, we’ll look at the tonal implications of the leading note property.

    Until then.

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    Hello, I'm Chuku Onyemachi (aka - "Dr. Pokey") - a musicologist, pianist, author, clinician and Nigerian. Inspired by my role model Jermaine Griggs, I started teaching musicians in my neighborhood in April 2005. Today, I'm privileged to work as the head of education, music consultant, and chief content creator with HearandPlay Music Group sharing my wealth of knowledge with hundreds of thousands of musicians across the world.

    Attention: To learn more about this, I recommend our 500+ page course: The "Official Guide To Piano Playing." Click here for more information.




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    { 1 comment… read it below or add one }

    1 Bernd Willimek

    Here is another definition of the leading-tone effect:

    https://www.academia.edu/36495364/What_is_a_Leading_Tone

    Bernd Willimek

    Reply

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