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Geek Talk: Scale Quantizer Options for a Jazz Improv Project
tl;dr
I need a scaler, note remapper, scale quantizer (hopefully crossplatform) with scale input (probably a number on 1490). So I’ll think out loud until a solution comes up.
Warning/Disclaimer
Some nerdy bits in there, in both “music theory” and program. Though I’m neither a coder nor a music theorist.
Back to the 'Pad
Hi there! It’s been a while…
Was mostly musicking on my MBAM1. Recently bought a 12.9" M1 iPad Pro (with 2TB!)… and I’m back to my beloved AUv3 workflows.
Yay! More posts by yours truly! 
The Project
I’ve had a project in mind for quite a while: some way to support Jazz improv through software, based on scale/chord relationships. Yes, I realize chord-scale soloing has limitations. Let’s just say I want to explore these limitations.
For context: I’m primarily a windcontroller player. Originally trained in classical sax playing… and in ethnomusicology (musical ethnography).
Nerdy music talk:
My approach to Jazz improv is similar to Earspasm’s diatonic noodling by ear. So, I typically fall in the “diatonic trap”.
Anyhoo…
The Need
I’d like a tool to help me improve my improv by guiding me through scale changes related to arbitrary chord progressions.
My “proof of concept” on the desktop has been to noodle over a groove on a single chord (call it "modal") with the scale quantizer in my favourite DAW. It was fun! I want to have the same thing… switching scales with a chord progression.
It’s more than I can chew, so I’m breaking it down in smaller problems. A big one is to associate scales to chords. Another one is to communicate scale information to the quantizer.
A much smaller issue is the quantizer itself. Turns out, it’s not quite that simple.
Scale Quantizer Options
Mozaic
Yes, I’ve tried a variety of Mozaic scripts. Thanks a lot for those, everyone who’s made one!
Turns out, none of them works the way I want, at a basic level. Even when they’re set to remap the notes, they end up skipping notes. Really not fun while improvising.
Maybe it’s an issue with legato playing (which is the way I play windcontrollers).
Yet I don’t have that same problem in my DAW’s pitch quantizer, in miRack modules, or even in Rozeta Scale! The way all of these work, the note I was playing before moving into an “invalid” note will keep playing. If I quantize to C Major (Ionian) and I play A then B♭, the A will keep playing. That’s exactly what I need.
I’m sure this is doable in Mozaic. I just don’t know where to start and I’m not sure I want to spend that much time learning Mozaic.
Rozeta Scaler
Rozeta Scaler would be a neat option… if it exposed the scaling parameters.
Tonality
An even better solution would be a Tonality module. In fact, my pet project as a whole would fit really well in Bryce’s lineup, I feel. The chorder already has chord/scale relationships built in. And it might become somewhat crossplatform.
Scaler
Similar idea with Davide’s Scaler 2. (I love the desktop version. Still haven’t bought the IAP for the AUv3.)
Drambo
Drambo could be fun. Haven’t tried the scale quantizers, there.
Rack Modules
I’ve mentioned miRack. The scale quantizers I’ve tried there work the way I need them to work. There are cool options in the whole “VCV Rack ecosystem” related to my pet project as a whole. As a benefit, those patches would work on several platforms, though I might need to tweak them between Cardinal, miRack, and VCV.
That’s probably my best bet.
The thing, then, is to switch between scales, arbitrarily. Several Rack modules take in notes to toggle the note filters (through “CV” inputs). So, if I want to move from C Major to F Major, I can send a B♭ to switch it on and a B to switch it off. Sounds doable… and complicated.
What I’d prefer is a way to just send the whole scale by a number. One way to do it would be to send the binary representation in a 12-bit number (so, 1 to 4095). Sending a 2 (i.e. 0000 0000 0010) would tell the quantizer to accept C♯. Sending a 3 (0000 0000 0011) would tell the quantizer to accept both C and C♯. Etc.
That’s basically the concept in TonalJS, AFAICT.
(I don’t care too deeply about Little Endian vs. Big Endian. So, it could be the reverse. Sending a 2 would tell the quantizer to accept B♭, a 3 for both B and B♭, and so on.)
Whew!
Of course, the key here is to find a way to send this number. Through 14-bit MIDI CC, maybe?
PureData
What might work even better than Rack modules would be a Pd patch. Problem there is that I don’t think we have a PlugData in AUv3, yet. That would rock! 
Over the rainbow
No, I don’t think RNBO is a valid option, in my case. Might as well code things in JUCE directly.
Heavy
So… hvcc?
Faust
Maybe even Faust (which can do MIDI)?
So…
As I’ve mentioned at the top, I’m no coder. I did dabble in Faust, C, PureData, Python, ChucK, JavaScript, Sonic Pi, Processing, Max/MSP, etc.
Allllllll this to say…
I want to build an elaborate workflow for software-enhanced Jazz improvisation yet I’m stumbling at something as simple as a note filter. 
Comments
For PD patches there is the mobmuplat app.
Re the "scales over chords" debate: playing scales over chords will not work well for playing mid-20th century standards in the jazz style of that period, but it is an excellent approach for some post-1970s jazz styles. It just depends on what you want to sound like.
Not sure I follow the technical requirements here. Is it that you want to be able to finger the same scale on your EWI throughout the solo, while the quantizer changes the notes to fit a scale that fits the chord progression as it progresses?
If so, this is not a shortcut to becoming a better improviser. The only real shortcut is developing your ear, and getting better at translating mental ideas into fingering on your instrument.
Playing one note on your horn and having a different note come out seems like it could potentially retard your growth. It could confuse your ear and your brain-finger connection.
That said, it sounds like a fun technical challenge to solve, and it sounds like a fun thing to play with just to see what kind of results you get out of it. If you get such a system built, it would be great fun to control it with ThumbJam or the Animoog controller. You could easily get some sheets of sounds solos out of it.
Atom 2 Piano roll is Au and can quantize to scales.
It's easy to build a Drambo project that will let you switch between arbitrary scales, e.g. by playing specific notes with your left hand (the scale switches) and play the chords to be quantized with your right hand.
The devil is in the details though - not sure how exactly the scale-switch-while-holding a chord would work.
Oh and btw, each note in Drambo's scale quantizer can be MIDI mapped to any CC or Note number so instead of two CCs forming a 14bit value, you have 12 CCs, one for enabling each note in the scale.
In MIDI mapping, you also have the choice to have a Note either toggle or switch momentarily, e.g. while holding a note.
Not quite.
I finger different patterns on my windcontroller as the scale which fits the progression changes and the quantizing shifts.
What you described would be like continuous transposition. That’s not what I want. I want to skip certain notes as I play… without the skipping to cause an abrupt stop.
As I go from, say, G Lydian Dominant to C Major Bebop, C♯ is filtered out (along with A♮) and A♭ is filtered in (along with C♮). If the note I was playing over G7 is now filtered out over CΔ7, it keeps playing.
Using 4Pockets Progressions with morphing chord changes can be really fun as I don’t know the progression in advance.
When I try it (by manually changing the scale input to the quantizer), it has a very strong effect on my learning, as I hear the voice leading and such.
Fair enough. It’s a reason I tend to avoid automatic transposition. And, at this point, I’m used to concert pitch even though I’ve trained myself in E♭ (alto sax) and B♭ (tenor sax).
Having said this… Since I typically improvise by ear (and have no issue translating mental ideas into fingerings on my WX11), I wouldn’t say it’s my main issue, here.
Good point.
In the end, I want to sound closer to ECM+Ornette than Berklee.
Mostly, I want to explore.
Something which could be fun to explore would be dynamic reharm.
Yep. And I’m glad it’s still in active development.
Issue there is that it’s not AUv3. At the same time, if I only do MIDI, I’d avoid IAA.
You got it.
While I tend to avoid IAA, similar controllers would be fun to use in this way.
Eventually, I’d like to make it all “microtonal”. In some ways, that can be easier.
As I play windcontrollers, both hands are busy playing one note at a time.