‘Parallel-12’, In 24-TET Tuning, On A Sequential Oberheim OB-6

Sunday Synth Jam: Synthesist Kris Lennox shared this live performance, Parallel-12, that features the Sequential OB-6, played in a 24 note-per-octave equal-tempered tuning (24-TET).

The 24-Tone Equal Tempered scale (aka quarter-tone or 24-TET scale) contains all the notes of the standard 12-note scale, but adds 12 more notes in between. The additional pitches open up a huge variety of new harmonic possibilities, allowing for both traditional harmonies and ‘alien’ ones.

This allows Lennox to freely move between familiar scales and chords and unfamiliar ones, creating harmonies that may seem strange or even disorienting to some musicians.

Here’s what Lennox has to say about it:

“The work is written in 24-TET (24 notes per octave), but I’m treating it as two stacked layers of 12-TET (12-TET is the foundation of Western harmony), each layer 1/4 tone apart. Hence ‘Parallel-12’.

Parallel-12 harmony is something I’ve been developing alongside full 24-tone harmony. I’ll upload a few pieces in this harmonic system in the near future. Some of the changes in Parallel-12 can be achingly beautiful.

The entire system of Parallel-12 is an unexplored landscape. But that’s partly because I’m developing it.

There’s so much to explore in the world of harmony. Vast, unexplored continents, I’d say. Sometimes it’s good to stay at home; at other times it is great to pack supplies and head off into the wilderness.

In Parallel-12, all chords sound ‘musical’ – but the changes between them can sound very, very unusual. In fact, the changes of this piece haven’t been heard before.

There are numerous Parallel-12 shifts throughout: the changes at the sudden filter shifts should be obvious (and some will be less so).

This was written in MIDI (well, written in the mind, then inputted in MIDI), which is a small nightmare in Parallel-12 (i.e the MIDI notes don’t correspond to the actual pitches, so the process takes a very long time). MIDI sent to the synth, freeing up the hands to play with the filters etc (plus in order to physically play this, I’d need more than 88 keys. And even if I did play it, I’d have no hands left to adjust the filter etc! Catch-22).

Time signature is 36/16 (or you could think 4 groups of 9/16).”

16 thoughts on “‘Parallel-12’, In 24-TET Tuning, On A Sequential Oberheim OB-6

  1. Super interesting. I really like changes even if it was just in regular old 12-TET, but the sound of those quarter-tone changes is new and wild and intriguing. If your goal was to get listeners interested in this new sound, you succeeded! That synth sounds awesome, also.

  2. Is 12-TET of any use besides with arpeggiation? Unless one reinvents the keyboard (again) it is inconceivable how to play 24 notes per octave by hand.

    1. “Unless one reinvents the keyboard (again) it is inconceivable how to play 24 notes per octave by hand.”

      There are multiple approaches that are used with 24-TET, including a) Pairing instruments and tuning half of the instruments up/down a half-step; using a microtonal keyboard (https://en.xen.wiki/w/Microtonal_Keyboards); using a keyboard that automatically tunes notes as you play; and just spreading the notes over two octaves of a traditional keyboard.

      1. Regarding a keyboard that automatically tunes notes, are you talking about Hermode tuning (which I once tried and wasn’t convinced) or is there something more recent out there?

        This track is beautiful, by the way, thanks for posting it.

  3. This is a clever approach, and a somewhat gentle way to introduce the new sounds (tunings). It’s akin to having a diatonic melody with some chromatic passing tones. You have kind of “standard” triads, and these 1/4 tone passing chord arps. (Am I understanding it correctly?)

    The rhythm is also interesting, and relatable.

    Beautiful work!! Thank you for sharing the music and your idea/approach!!

  4. The same thing can be done with a Korg Minilogue or Prologue. Set the filter tracking to 1/2, turn up the filter so it rings, and you’re off and running. You’re only getting the ringing from the filter, but it is 24-TET. It sounds weird, but it’s a lot of fun.

  5. A large number of synths let you set key scaling to something besides 100 cents per note. So 50 cents per “key-semi-tone” is one way. Another approach would be to use a foot controller to switch between a standard layer and a +50-cent layer. Or just have two MIDI channels with the second at +50.

    There are more complicated approaches, like semi-sharps and semi-flats: For example, having C# be +50 of C, Eb as -50 of E, F# & G# as +50 of F & G respectively, and Bb as -50 of B. You’re still having 12 tones per octave, and a standard diatonic scale, but you get these not very sharped, and not very flat notes away from the C major.

  6. 12 tet is not the foundation of western harmony. it is a was invented to play western harmony on a keyboard with a manageable number of keys (even in the baroque there were keyboards with much more then 12 keys which turned out to be un-playable)
    i feel like i am missing the point -detuned arpeggios while turning the filter knob is a lot of fun for sure, but hardly unexplored territory.
    >> “There’s so much to explore in the world of harmony. Vast, unexplored continents, I’d say.” – just look at the history of western “classical” music of the last century for a gaziilion ideas how to expand the harmonic horizon.

    1. If you think 12-tone equal temperament is NOT the foundation of western harmony, then perhaps you should enlighten us as to which tuning system is?

      Also, I thought that the purpose of 12-tone equal wasn’t to create a manageable number of keys– as keyboards had somewhat settled on 12 notes, but the “equal” part was to enable freedom to change keys, and have all keys sound equally out of tune.

      1. “equal temperament” is a compromise, as you say yourself, not the foundation. eg just listen to a brass ensemblein in pure tuning

        1. I’d argue that any brass ensemble where members pulling down the thirds of its major triads, and slightly widening its 5ths, etc, are still playing instruments that are designed to play 12 ET. They are doing little ad hoc tweaks to make chords more in tune. It’s similar to Hermode tuning.

          Anyone who has tinkered with Hermode, knows that it can be “tricked” into making a fool of itself. Thankfully, 12 ET is the FOUNDATION.

          I’ll concede that it may be a chicken-egg situation. Our scale and chords are chosen because of simple pitch ratios. 12 ET was chosen because it provides close approximations of many of those intervals. Yes, we could have divided an octave into many more slices, but things would have become unwieldy.

    2. Looking at his channel and background, I think he is familiar with western and classical music? Maybe he is bored with it lol

      Also, didn’t western harmony develop after tuning was standardised, rather than before? Wouldn’t this mean 12tet is in fact the foundation of western harmony?

  7. I first became aware of Kris’s work here:


    After that, I became an acolyte. Take in his YT channel & prepare to be knocked out. The guy casually hands you a new synth lesson with every tangent. You want a “new” synth? Its two layers down in the one you already have. Kris is a good addition who fits well (loosely) between Nick Batt & Daniel Fisher.

  8. I used to experiment with this kind of custom tuning type stuff on my korg z1 and also the ob12 iirc.
    . It was all by ear though, not based on theory or anything like that.. Occasionally it produced some really funky and cool results… But yeh it was time consuming

Leave a Reply