MPE and microtonality

I’ve recently been reading up on microtonality; the theories of Erv Wilson (pretty mindblowing), and ‘generalised keyboards’ like the MicroZone/Lumatone.

I’ve seen a couple of posts on other forums raising the problem of MIDI’s 128 note limit when you’re working with scales with eg 53 divisions of the octave. (The Lumatone has 288 keys. The MicroZone U990 has 810.)

One approach to this is “channel per octave”, which is apparently supported by certain plugins like Pianoteq and SurgeXT, but very few. I was slightly surprised to come across this puzzle, because I thought it was done by sending pitchbend. Would MPE-style pitchbend per-note work as an approach to this, even for non-MPE controllers…?

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Yes there are a bunch of tuning plugins and several DAWs that already use MPE to achieve microtonality. These will work with software and hardware synths that have MPE support, so long as that support has been implemented properly in the instrument (eg there are some hardware MPE synths that do not follow the spec properly, by failing to act upon MPE pitch bend messages that are sent immediately before the note on messages).

Bitwigs Micro-pitch device: Micro-pitch Device Tutorial | Bitwig

Ableton Microtuner device: Microtuner | Ableton

Ableton 12’s new tuning system: https://help.ableton.com/hc/en-us/articles/11535414344476-Tuning-Systems-FAQ

Oddsound MTS-ESP - this has several different methods for achieving instrument retuning. This plugin is most famous for popularising the modern use of MIDI Tuning Standard (MTS) but I believe it has an MPE mode too: ODDSOUND

Entonal Studio (which is also available at a much lower price for iOS) is a similar story, can use MTS but also MPE: https://entonal.studio

Infinitone - same sort of story with this one I believe, but its been a while since I trialled it. https://infinitone.com

There may be others that Im not aware of. I dont have special knowledge about the MIDI note number limitation that you mention, probably because the solutions I’ve tried do get round that using MPE pitch bend. For example, Ableton 12s built in tuning system includes some examples that have a large number of divisions, eg 72-EDO and works quite well with the pads of their Push controllers.

Speaking of Ableton, when they added that stuff to version 12 they also made a website that lets you learn and explore this stuff in a web browser. A glorified marketing exercise thats pretty educational. There is an icon on the top left of the site that lets you jump into the blurb and details of a bunch of tuning systems, if you get bored of going through the site in a linear fashion. https://tuning.ableton.com

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Thanks…lots to look at there, and some interesting gotchas.

I don’t know how the Lumatone works, but I guess, if it supports channel-per-octave, but not MPE-style pitchbend-per-note, it would be possible to build a converter in something like Bome…(?)

If this is a problem for Lumatone users (I get that impression), it might be solved by MIDI 2.0, since they’re keen on embracing that, and it seems to solve the microtonal problem somehow. (?) Then again, perhaps support for MIDI 2.0 in software might take a while to catch on too.

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I lack Lumatone knowledge. I skimmed a section of their manual and it sounds like they are more used to pairing things with a much more limited set of 3rd party solutions, some of which were probably imagined before MPE gained traction. Eg this is mentioned in their manual: Hπ Instruments | universal tuning editor but I dont have the time to read the technical details of that one, or investigate how that solution may have evolved over time.

Yes they claim they will implement some MIDI 2.0-based solutions as soon as it is practical. But yes it will take time for a broader MIDI 2.0 ecosystem to evolve, and also there are many different aspects to MIDI 2.0 and there is no certainty about which aspects of MIDI 2.0 will be adopted by various makers of hardware and software. MIDI 2.0 has the facility to transmit very precise tuning information as part of every note on MIDI message, every time you press a key, and thats the bit that would offer a sensible solution. But its one of the least mentioned aspects of MIDI 2.0 so far, so at this stage nobody knows what adoption will be like in future.

I expect that for quite a long time to come, MPE offers by far the biggest choice of compatible synths/instruments. Synths that support MTS-ESP are in second place, support for that has gained some traction via a fair handful of notable instrument plugin developers supporting it. Other options are far more niche and bespoke and I cant say much about them due to a lack of personal experience.

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The issues with quickly discovering the technical reality of Lumatone are caused by the price making it very niche, so not a lot of technical chatter online by actual users. And I dont think a community forum that was planned for 2024 came to fruition.

And their own sites mentioning of MPE tends towards the defensive. They probably had potential users asking them questions about the additional expressive dimensions of touch that MPE controllers offer, and since thats not part of their offering, they just go on about how thats not part of their vision. Their talk about a MIDI 2.0 future tends to be part of this defensive talk too, makes it sound like they are trying to bypass the whole MPE era. This is fair enough, except it gets in the way of searching for talk about the other aspect of MPE which could still be highly relevant to Lumatone, making use of per-note MPE pitch bend messages to provide a tuning solution.

In theory yes, if a device really outputs all the required info every time a note is pressed, you could convert that info into MPE messages. But it might not be trivial, and I dont know if Bome is excellent for this task - most of the realtime MPE processing and conversion work I’ve done is via my own scripting and programming, using traditional computers, languages and MIDI libraries, where I know I dont run into any additional limitations. And if the device doesnt output all of that data every time a note is pressed, you’ll end up having to build the details of the desired tuning into your own code, and the size of the mission will quickly balloon.

If I were interested in the Lumatone myself, I would probably contact Matt directly, and discuss the detail, try to have a MPE conversation that focusses on the pitch bending tuning data not the other dimensions of MPE. Maybe this has already been solved for all I know, or several existing solutions could be glued together to get the desired result, but I dont have the time to do more research on this.

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I did a little bit more Lumatone digging and I was deeply unimpressed.

Heavy on promises in videos when it came to extra editor functionality, community-generated online mappings site, low on actual progress in any of these respects despite the years flying by. I am left with no sense of momentum.

It looks to me that when it comes to microtonality, theres really nothing built in, 3rd party stuff does all the work. Talk about a missed opportunity. You’ll either have to use tuning stuff built into certain instruments, or use the sort of solutions I linked to in my initial post, to get microtonal results. On its own, theres no tuning data coming out of the Lumatone that you could then convert into another format such as MPE. Just normal notes and channels. Whether you even need to use more than one channel likely depends on other details of your mapping, eg whether each physical button is mapped to a completely unique note, as opposed to being repeated in strategic locations.

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Cool, thanks for the detailed answer. :slightly_smiling_face: :+1:

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No problem, just keep in mind that I relied on their most obvious videos etc for that info, along with release notes for firmware and editor, so there is always a chance I missed something that it does have built in these days.

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The smaller Striso Board appears to combine both. It uses a similar isomorphic layout (which is perfect for various kinds of microtonal tunings), but the performance data is sent as MPE MIDI over USB. It has three parameters of expression (up/down, left/right, forward/backward) + note on velocity, I think.

I don’t own one but it came to mind reading this discussion.

Lumatone, as a controller, does not have a center neutral expression parameter that could be used to wiggle around a center for pitch bend. It does however have polyphonic aftertouch. Most performances on the instrument are a bit more “pianistic” in that they work with stable pitch centers (as opposed to adding expressive vibrato like with the Osmose).

Here is an exhaustive resource concerning plugins supporting microtonality:

https://en.xen.wiki/w/List_of_microtonal_software_plugins

About half a year ago I was deliberating between going down the MPE (in my case: Osmose) route or exploring microtonality (likely with a Lumatone). I ended up choosing Osmose. But who knows, I might give it a shot if I can afford one. The music coming out of Lumatone has been quite innovative in my opinion. Look up Zhea Erose. :slightly_smiling_face:

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Hey everyone! Just thought this link may be of interest to folks here: Surge Synth Team Tuning Guide

I’m on the Surge team, to be clear. Also to be clear, we’re a volonteer team and all our stuff is free, just so you don’t think I’m trying to sell you something. Anyway, that’s a page we have made to explain the tuning implementations we’ve made in Surge and our other products.

Few things to note:

In the most zoomed-out technical sense, there’s two approaches to making microtuning work. Either you modify the MIDI data going in to the instrument to play the tuning you want, or you change the midi-note-to-frequency function inside the instrument and leave the midi as it is. As you can see in that link, we generally prefer the latter approach, with MTS-ESP and scala files as our preferred standards. Pitch bend/MPE/Poly Expression can work well too, and some people prefer it.

If using MPE/PolyExp and microtuning, the important question to ask is how/if you want those two to interact.

Hardest thing to make workable is definitely pitch-slide playing, say on a Linnstrument. In an unequal tuning, sliding from field A to B might land you on a different frequency than if you played B directly. Tunings with more or fewer steps than 12 might get a bit unwieldy or too precise, etc etc. I don’t have a Linnstrument but am told that getting an intuitive play-feel for pitch slides is really tricky. Maybe some of the pitch-bend based tools out there can help with that. IDK. Definitely most software instruments with internal tuning don’t handle this particular case well.

On the other hand, you may be using MPE just for timbral expression, not pitch. In that case instruments with internal tuning will work great, I would just use those. Then the tuning is, so to speak, dealt with already and the poly expression can serve its main purpose of being expressive.

It’s also quite common that people otherwise not interested in MPE/poly expression want to use it only for tuning purposes. In my honest opinion the main reason to do that is if you have some synth you already know and love, which doesn’t have any other way of microtuning it.
If you’re not attached to using a particular synth, there are plenty nowadays with actual built-in tuning features. All approaches have their drawbacks, but pitch-bend based ones have definitely thrown the most wrenches in my wheels over the years, for what it’s worth. Though I do sometimes use it for a couple synths I love which don’t have MTS-ESP (Izotope Vocalsynth, Madrona Labs, etc).

Good luck exploring!

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Ableton’s implementation in Live 12 is MPE based, but handles pitch sliding correctly on an unequal tuning.

I have not tested on other DAWs, but it seems like that’s where this should be handled, so as to not burden individual synth developers with such a cumbersome wheel to reinvent.

I would say the downside of this approach is that the MPE spec gives us a bend range of -/- four octaves, which is a low enough resolution that your custom tuning might not be possible. (Two octaves would be a more reasonable compromise, and one would have been ideal.)

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Ok cool! So if you slide from one field to another on a Linnstrument, you get the right target pitch in the end (same as if you played the field you ended on directly)?

I totally agree with the DAW sentiment in a way. The way I think about this stuff, the tuning of a song is a feature of the whole arrangement, somewhat like tempo and time signature. It was always strange to me to have to set it individually per instrument. I’ve been using the MTS-ESP system for a few years now (ODDsounds master and others), and that’s the closest you can get today because it gives you one central tuning interface, though it is in a plugin, not a DAW.

When it comes to developer burden, well… it’s a bit tricky. If there were one single standard that devs could implement that would reliably integrate with DAW features to produce a tuning workflow that everyone agreed could be satisfying, then we would all just implement that one and be happy. MPE is a hundred times better than nothing, but it isn’t the unanimous favorite we need, sadly. You’ve pointed out one problem with it, there are also others.

I won’t go on but to name one example: If you’re using VST3 plugins, and your midi is hard-quantized, there’s a thing that happens where the plugin won’t know which pitch bend message belongs to which note.

That there is the reason for it. Knowing that sooner would’ve saved me hours of troubleshooting MPE setups which sometimes inexplicably would sound hilariously out of tune. That’s a very technical bit of info for users to keep track of.

But I digress. Like I said, some folks get great results with MPE or other pitch-bend based tuning workflows. And the ones I use aren’t flawless either (MTS-ESP tuning changes aren’t sample accurate for example, so you gotta move that automation a little early etc etc). The journey is figuring out what will work for your music. Which depends deeply on what music that is.

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Also worthwhile looking at:
https://wilsonic.co/ (and now open source on github too)
And Infintone has released a much expanded/updated version 2 at their original web address - they provide a free trial.
As a new user limited to one address per post

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Yeah those are good too! Both listed on the link I posted as well (under MTS-ESP sources).

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So…Andreya, if you were going to design a microtonal MIDI controller with a large number of keys like the Lumatone, what approach would you use…?

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