• Jazz Musicians: “What’s The Most Unpleasant Interval You Can Play In Jazz Theory?”

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    Can I show you what the most unpleasant interval in jazz music is?

    Although there are so many notable intervals that are unpleasant — just like the tritone which was known as the devil in music — there’s something about this particular interval that stands it out as the most unpleasant interval.

    Let’s start out by taking a look at the consonance and dissonance of intervals.

    Consonance Vs Dissonance

    An interval is a product of the relationship between two notes (agreeable or not) which may be played or heard together or separately

    In this segment, we’re focusing on the part that says “agreeable or not.”

    There are other ways to say “agreeable or not” and it includes the following:

    Complete or incomplete

    Pleasant or unpleasant

    The use of “pleasant” and “unpleasant” sounds good. However, in theoretical terms, an interval is either said to be consonant or dissonant.

    Let’s take a closer look at these theoretical terms.

    Consonance — Explained

    Consonant intervals are intervals that sound pleasant and complete when played. When the intervals below are played, they sound pleasant and have a sense of completeness:




    …as opposed to the tritone (the diminished fourth interval) that sounds unpleasant; with a sense of incompleteness:


    All major and minor third intervals are consonant:









    All major and minor sixth intervals are consonant as well:









    All perfect fourth and perfect intervals are consonant; although perfect fourth intervals can also be dissonant in certain situations.

    “What Is Dissonance?”

    The tritone is a classic example of a dissonant interval and I mentioned it earlier when we were talking about consonant intervals.

    “But There Are Other Dissonant Intervals…”

    All major and minor second intervals:

    The major second interval

    The minor second interval

    …and major and minor seventh intervals:

    Major seventh interval

    Minor seventh interval

    …are dissonant.

    When a dissonant interval is played, it has the tendency to move to a consonant interval and this movement is called resolution.

    Here’s what resolution feels like:

    From unpleasantness to pleasantness

    From incompleteness to completeness

    From dissonant to consonant.

    The resolution of the tritone below is a classic example:



    The Most Unpleasant Interval In Jazz Theory

    The most dissonant interval in Jazz is the minor ninth interval and in the rest of this segment, I’ll be showing you where to find the minor ninth interval in scale tone chords.

    But before we go into all of that, let’s discuss briefly on the minor ninth interval.

    Introducing: The Minor Ninth Interval

    The minor ninth interval is the compound interval that is closely related to the minor second interval. So, if you’re familiar with the minor second interval, it’s easier to understand the minor ninth interval.

    Lowering the major second interval (which is the interval between the first and second tones of the major scale) by a half-step produces the minor second interval.


    …is a major interval and that’s because it’s an interval between the first and second tones of the C major scale:

    Lowering D:

    …by a half-step to Db:

    …produces C-Db (a minor second interval):

    C-Db can either be a simple or compound interval:

    The minor second (simple interval):

    The minor ninth (compound interval):

    So, the minor ninth interval starting from C consists of C and Db:

    “For Your  Reference, Here Are All The Minor Ninth Intervals On The Keyboard…”

    C minor ninth interval:

    C# minor ninth interval:

    D minor ninth interval:

    D# minor ninth interval:

    E minor ninth interval:

    F minor ninth interval:

    F# minor ninth interval:

    G minor ninth interval:

    G# minor ninth interval:

    A minor ninth interval:

    A# minor ninth interval:

    B minor ninth interval:

    Example #1 — “The 7-chord”

    The 7-chord in the major key is basically the diminished triad. In the key of C major:

    …the seventh tone of the scale is B:

    …and the 7-chord is the B diminished triad:

    Adding a seventh and ninth tone to the B diminished triad produces these two 7-chords:

    B half-diminished seventh:

    B half-diminished seventh [flat ninth]:

    Although both chords are dissonant (because diminished chords are generally dissonant), the dissonance of the B half-diminished seventh:

    …is tolerable, while that of the B half-diminished seventh [flat ninth]:

    …is intolerable.

    Attention: Please, plunk down both chords on the keyboard and let your ears be the judge.

    The B half-diminished seventh [flat ninth]:

    …is intolerably dissonant because of the minor ninth interval between its root and ninth tone (B and C):

    Example #2 — “The 5-chord”

    The G dominant eleventh chord:

    …which is the 5-chord in the key of C major:

    …sounds terribly dissonant because of the minor ninth interval between its third tone (which is B) and eleventh tone (which is C):

    In jazz, the eleventh tone is considered as the “avoid note” because of the minor eleventh interval it forms with the third tone.

    Example #3 — “The 3-chord”

    The 3-chord is a minor quality chord.

    In the key of C major, here are two common 3-chord examples:

    The E minor triad:

    The E minor seventh chord:

    Adding the ninth tone to the E minor seventh chord:

    Ninth tone (F):

    E minor seventh chord:

    …produces the E minor seventh [flat ninth] chord:

    …which is terribly dissonant because of the minor ninth interval between its root and ninth tone (E and F):

    …and the tritone between its fifth and ninth tone (B and F):

    Example #4 — “The 1-chord”

    The C major eleventh chord:

    …is the 1-chord in the key of C major:

    But the minor eleventh dissonance between the third and eleventh tones (which are E and F):

    …makes the C major eleventh chord very unpleasant to use as the 1-chord in the major key.

    Final Words

    Yes! Jazz musicians love dissonance. But the minor ninth interval has an intolerable degree of dissonance that makes it the most unpleasant interval in jazz harmony.

    In a subsequent lesson, I’ll show you how this interval can be applied in the formation of dominant chords.

    See you 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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