Octatonic scale writing help!

Discussion in 'Music Theory, Lessons & Techniques' started by Car Bomb, Aug 27, 2017.

  1. Car Bomb

    Car Bomb GO BOOM

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    So I'm doing some prepro, getting ready to hit the studio and I made a riff that after some research turned out to be in the octatonic scale (double diminished/whole half). I'm loving the vibes I'm getting from this combination of notes, its kinda bluesy with allot harmonic minor vibes seams to have a lot of lazy sounding notes. But any how I managed to piece together another riff in this scale and got more of the same vibes. Now I'm looking to make a section around a fun chord progression and this is where I'm lost and things aren't coming together. Basically want to know what chords fit on each note. I believe I only need to learn the chords for the first two notes as they just repeat in the same intervals after. Let me know if your familiar with this scale and if you know of any good progressions or songs that use this, all I can find is jazz players who use it for improve.
    Here is my rough prepro with the two riffs.
    https://www.dropbox.com/s/a4rhsqhb1f527vt/back bacon.mp3?dl=0
     
  2. Mr. Big Noodles

    Mr. Big Noodles Theory God

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    I can't listen to your work right now, sorry. I'll check it out later.

    The half/whole mode is closer to the standard tonal harmonic system than whole/half, so i will proceed from there. Let's do this from C.

    C D♭ E♭ E F# G A B♭

    I use those specific spellings to emphasize certain harmonic relationships. For example, I could have gone C C# D# E... but I feel this helps to map out the tonal possibilities better. We will end up respelling some of those notes though. These are the scale degrees:

    1 ♭2 ♭3 3 #4 5 6 ♭7

    If you spell every possible triad using those pitch classes from C, you get the following:

    C = C E G (1 3 5)
    Cm = C E♭ G (1 ♭3 5)
    C° = C E♭ G♭ (1 ♭3 ♭5)
    C (♭5) = C E G♭ (1 3 ♭5)

    That last one is not a traditional triad, and I won't focus on it so much. Notice that for the last two chords, I used an enharmonic spelling to get the diminished fifth in there (rather than an augmented fourth) so we can identify the fifth of those chords properly.

    There is a rich harmonic variety within the collection for chords on the first degree, and as you mentioned, that transposes to degrees ♭3, #4, and 6. Within that H/W mode on C, these are the most harmonically rich scale degrees:

    1 = C, Cm, C°, C(♭5)
    ♭3 = E♭, E♭m, E♭° (maybe better spelled D#°), E♭(♭5) or D#(♭5)
    #4 = F#, F#m, F#°, F#(♭5)
    6 = A, Am, A♭, A(♭5)

    Let's call this "group A." You can kind of approximate some standard chord changes out of this. C Am F#° is I vi vii°/V. It's kind of incomplete, but it's worth noting. Try mixing those chord qualities and see what you can come up with. By the way, you can only get minor and diminshed sevenths on those chords.


    To harmonize rest of the scale is pretty easy: the only triads you can make with ♭2, 3, 5, and ♭7 as roots are diminished. And you can add the diminished seventh to good effect. These chords all contain the same pitch classes. Respelled:

    C#° = C# E G B♭
    E° = E G B♭ D♭
    G° = G B♭ D♭ F♭
    A#° = A# C# E G

    Let's call these the "group B" chords. These are a bit harder to work with, and I think they are better thought of as being tied to the group A harmonies.

    Since there is no traditional tonal resolution built in to this collection, we need a workaround. You can sort of imitate functional mannerisms by exploiting a relationship called the common tone diminished seventh chord. I would do these within group A, so your resolutions look like this (ct°7 chords in red):

    C°7 > C (or Cm)
    E♭°7 > E♭(E♭m)
    F#°7 > F# (F#m)
    A°7 > A (Am)

    There are technically common tone diminished seventh relations between the group B and group A chords, but. They are not satisfying to my ear.

    This progression sounds reasonably tonal to me, albeit with some jarring root movement:

    C Cø7 C#°7 Am F#m G° C°7 C

    I iø7 ♭ii°7 vi #iv v7° i°7 I

    You can hear that some basic consonance/dissonance principles are at play: perfect fifths are more consonant than diminshed fifths, and I am interested in presenting the tonic, moving away grom the tonic, then moving back to the tonic. The group A chords act as harmonic goals, and the group B chords move between them. A common tone °7 chord provides the necessary neighbor motion to approximate a cadence.
     
    Last edited: Aug 29, 2017
  3. bostjan

    bostjan MicroMetal Contributor

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    I don't know why, but I can't access the file, even though I have a dropbox account.

    @Mr. Big Noodles did a perfect job explaining, as always.

    The octatonic diminished scales, which are modes off of each other, usually come up in guitar method books with a blues context as "that funky scale you throw down over the V chord." If you use it as it's own riff farm, in a metal context, though, the idiom is completely different than that.

    As a diminished scale that has only diminished modes, all of your chords strictly out of the scale will be diminished. Let's pick an example of Eb as the tonic.

    ---------------------
    ---------------------
    ---------------------
    ------7--------------
    ------6--------------
    ------5--------------
    ------4--------------

    Move that position anywhere it fits, depending on the tonic you want. The formula for that one is just 1 b5, nothing too spicy.

    -------3------------
    -------2------------
    -------3------------
    -------2------------
    --------------------
    --------------------
    --------------------

    That has a much higher voicing, but adds some flavour.

    Another lower voicing with some colour in it would be:

    -------------------
    -------------------
    ------2------------
    ------x------------
    ------3------------
    ------2------------
    ------4------------

    Then as far as where to move that shape, pick a tonal centre somewhere around where you are riffing, and stick your anchor point there.
     
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  4. Mr. Big Noodles

    Mr. Big Noodles Theory God

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    Just listened to the track. Single note riff stuff, and pretty good at that. I'm not sure that it makes compositional sense to bust out a chord progression, though I can imagine a few possibilities.

    One thing I would do is pay attention to form.
     
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  5. Car Bomb

    Car Bomb GO BOOM

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    Sorry guys! Had notifications turned off. That helps allot, wish I had read this earlier. I tried a bunch of chord progressions by painful trial and error and none worked in a way that fit so I came up with a melodic trem harmony that works nicely. I'm gonna try to put this to use on a softer intro. Here is the updated version has a couple cheater notes and the last riff is not octatonic at all.
    https://www.dropbox.com/s/qzv8b3k1nf9ufjj/5back bacon.mp3?dl=0
    I think splitting the a and b chords will help allot I kept writing into an unsolvable dead end before.
     
    Last edited: Sep 2, 2017
  6. Aion

    Aion SS.org Regular

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    Sorry I'm a little late to this party, and it seems like you've mostly got what you needed for this particular question, but if you want to re-explore this or do any work with alternative/synthetic scales in the future, might I suggest exploring a more modal or synthetic form of harmony. One way to start this is to write harmonies in stacked fourths and fifths instead of thirds. The diminished scales are a cool way to explore this because in some cases you can use absolute fourths/fifths (perfect fourths, augmented fourths, diminished fifths, perfect fifths), but other times you can use relative fourths and fifths from the scale (diminished fourths, augmented fifths).

    What I mean, using stacked fourths in a C Whole-Half scale you can use C-F-A for relative fourths, or C-F-B for absolute fourths. You can do similar things with other intervals, absolute or relative 3rds, 6s, 7ths, or intervals wider than an octave. You can do 2nds, but it's very dissonant, which can be a cool effect, but I personally find it too dissonant for extended use. In any case, you can experiment with both relative and absolute intervals, find where you find one thing effective vs the other. It's worth noting that even if you have dissonant intervals, the more spread out they are the less dissonant the chord as a whole will typically sound. This can help to create complex harmonies that aren't so nasty sounding. I'll also mention that while this technique works with diminished scales, I think it really shines with asymmetric, non-typical scales (typical scales being any of the seven note, major/minor western scales). In any case, might be a fun thing to experiment with later. It won't necessarily give you a fun progression, but it can help create a harmonic background to explore within.
     
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  7. Mr. Big Noodles

    Mr. Big Noodles Theory God

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