randy's Recent Posts

Sumu isn't adding the folder I've assigned for my own Vutu-generated partials when clicking the three dots in the Partials section and importing.

When you select the folder containing your .utu files, they are imported into compressed .sumu files in the Sumu Partials folder. The directory and any directores below it that you select, will be searched and a similar tree of directories made in the Sumu Partials folder. It's like "sync" for all the .utu files.

I'll try to improve on the UI a bit and make a demo movie or something for the next release.

Wow, the formatting on the patch text is crazy, talk about out of the box!

Yes I want to add visual indicators but with 64 channels per patch it's a whole new design problem, and one left for later.

A single sumu instance in a blank project on default patch brings CPU meter to 46 percent.

That sounds about like what I'd expect.

CPU is totally dependent on the number of voices active, which is set in the input module. If a patch uses too much CPU you can turn down the number of voices. A couple of the patches are set at 16 voices and no computer I have can run them now.

It's prerelease software and optimizing has not been a focus at all. If it is interesting to you but not usable for you now I hope you'll keep an eye out for future releases.

FYI, I think I have introduced a bug affecting performance on MacOS / Intel. In a previous beta, it was running fine on my 2015 Retina MBP and that's a machine I am targeting. But on reading the reports of unusable performance I tried the latest beta and it's behaving much as people describe: unusable. I'll look into this ASAP.

Will Vutu ever be integrated into Sumu's UI?

I've got no plans to do that - one reason is design and one is legal (Loris being GPL software). Practically speaking I'd have to re-implement Loris, which is not happening any time soon.

[edit] Oh and thank you for looking into the demo noise.

Not a problem, I rely on your feedback to find the right balance!

Sumu is an additive instrument that I've had in the works for a long time. Now that it's nearing completion and heading towards a public beta soon I'm going to break with the way I normally do things and put some detailed info out ahead of its release.

Sumu preview

Sumu is another semi-modular instrument. It shares the general appearance of its patcher-in-the-center design with Aalto, Kaivo and Virta. As you can see, it's on the more complex end of the spectrum like Kaivo. Everything is visible at once and there are no tabs or menu pages to navigate, which suits the way I like to program a synthesizer tweaking a little something here, a little something there.

In the same way that Kaivo brought two different and compatible kinds of synthesis together, combining granular synthesis with physical modeling, Sumu combines advanced additive synthesis with FM synthesis.

What's most different about Sumu compared to my other synths is that the signals in the patcher are not just one channel of data, but 64—one for each partial in a sound! By keeping all these channels of data independent and still using the same patching interface, Sumu offers a very usable entry point into additive synthesis, and a range of musical possibilities that have only been approachable with high-end or academic tools or just coding everything yourself... until now.

Sumu oscillators

Each of Sumu's oscillators is the simplest possible kind of FM:a single carrier+modulator pair. And the modulator can produce a variable amount of noise, which like the modulation ratio and depth can be controlled individually per oscillator. In a single voice there are 64 such pairs. Obviously a lot of sounds are possible with this setup—in fact, with the right parameters varying appropriately we can reproduce any musical sound very faithfully with this kind of oscillator bank.

Sumu partials

There are a few ways of generating all of those control channels without the kind of painful per-partial editing that some of the first digital synths used. The first is the PARTIALS module up top, where you can see a diagram of all the 64 partials over time. This is like a sonogram style of diagram where x is time, y is pitch, and thickness of each like is amplitude. There is also an additional axis for noisiness at each partial.

A separate application will use the open-source Loris work by Kelly Fitz and Lippold Haken to analyze sounds and create partial maps.

Sumu envelopes

Another way of generating control data is with the ENVELOPES module. It’s a normal envelope generator more or less—except that it generates 64 separate envelopes, one for each partial. Generally you would trigger them all at the same time, but each does have its own trigger so they can be separate. Using the “hi scale” parameter the high envelopes will be quicker than the low ones, making a very natural kind of lowpass contour to the sound.

Sumu pulses

Finally on the top row there’s the PULSES module. This combines an LFO and a randomness generator into one module. The intensity and other parameters of the pulses can be different for every partial. So this makes modulations that can be focused on a certain frequency range, but you don’t have to mess around editing partials one by one. You could also, for example, use the pulses to trigger the envelopes all at different times.

The PULSES module was inspired by my walks in a small canyon near my house, and listening to the very finely detailed and spatially spread sounds of water running in a small creek. Each drop contributes something to the sounds and the interplay between the parts and the whole is endlessly intriguing. 

To make a water drop sound, two envelopes are needed at the same time: a rise in pitch and an exponential decay in amplitude. So PULSES lets you put out two such envelopes in sync. Then of course we generalize for a wider range of functions, so we can find out, what if the drops were quantized, or had different shapes over time? A voice turning into a running river is the kind of scene that additive synthesis can paint very sensitively. The PULSES module is designed to help create sounds like this. 

Sumu space

The SPACE module lets us position each partial in the sound independently. Coming back to the creek idea, we can hear that certain pitch ranges happen in certain locations around us due to the water speed and the resonances of different cavities. This all paints a lively acoustic scene. By positioning many little drops independently, while allowing some variation, we can approximate this kind of liveliness.

This module centers around two kinds of data, a set of positions for each partial known as home, and a vector field: a direction [x, y, z] defined at each point in a 3-dimensional space. There will be a set of both the home and the field patterns to choose from. By offering these choices, and a small set of parameters controlling the motion of the partials, such as speed, the homing tendency, and the strength of the vector field, we can quickly create a wide variety of different sonic spaces without the tedium of editing each partial independently. 

The RESONATORS module is very simple and inspired by the section of the Polymoog synthesizer with the same name. It’s simply three state-variable filters in parallel, with limited bandwidth and a bit of distortion for that “warm” sound. In Sumu, a synth we could otherwise describe as “very digital,” it’s nice to have a built-in way of adding a different flavor. 

So I have this interface you see above, and a sound engine, and I'm working feverishly to marry the two. To enable all of the animations and the new pop-up menu, I wrote a whole new software layer that provides a completely GPU-based UI kit and interfaces directly with the VST3 library. Because it's been such a long process this time, I'm going to "build in public" more than I am used to doing, and have a public beta period. My plan is for this to start in December. (Yes, of 2021, smarty pants.) Meanwhile I hope this information gives you interested folks something to whet your appetites, and even a basis for starting to think about what kinds of patches you might want to make.

Sumu is too big when I open it on my MacBook Pro inside Logic. How can I resize it and make it smaller?

The resizer is in the bottom right corner. If it can’t be moved onscreen, then hopefully you can resize your screen resolution and / or rearrange displays as a workaround. Once you have the size you want, be sure to save it in your DAW and it should open at your chosen size from then on.

Or if none of this works, we’ll update soon.

Issues we hear and are working on:

  • demo noise too loud: we'll release a minor update within two weeks
  • EUR payments don't work: this should be fixed and deployed now!
  • Bundle discounts are confusing: we'll make the logic more clear and send out an email this week.
  • crashes on DAWs including Reaper, Cubase, FL: will fix for next update
  • too-big window size on some DAWs: will fix for next update

Like our other synths, each patch in Sumu has a fixed number of free-running voices set in the INPUT module. Because all of our synths can make notes by turning dials, just like modulars, whether you play a note or not, that max number of voices is always taking up CPU.

So for those few patches that were set at 16 voices because they sounded too cool to resist that way, you can turn the number of voices down to 4 or something.

And yes, it's truly still a CPU-heavy synth. Like our other ones it will get much better over time as I optimize.

There are a lot of people having issues with the calculation of the bundle and discounts for licenses they have. Thanks for your patience with us as we iron out the wrinkles—we'll have a look and revise this very soon.

I can't get over the really loud and harsh white noise that repeatedly comes in and out in the demo. Currently dissuading me from continuing to play with the plugin. Any chance that can be toned down?

Thanks for the feedback, I'll turn it down in the next Early Access release.

@euanek are you logged in?

Also if you have all previous products, the bundle does not really apply.

We're working hard to ship this month. There will be an Early Access version first, then 1.0 with MPE support. Lots more info on Early Access soon.

There's not a way to do this now, but it would be a cool feature to have. I'll put it on the list for the next version.

Aalto and Kaivo work just like other plugins do in Ableton, using MIDI map mode:


The kind of physical modeling I used in Kaivo's body was invented for solving differential equations. These were often electrical - for antenna design for example. More recently people began using them for synthesis. The book Numerical Sound Synthesis by Stefan Bilbao is the definitive guide.

Thanks for the kind words!

I could do this but it might break people's patches! I will have to check.

SInce it's a granulator can't you play things slower, to get a longer duration? If you want to import a longer file, you could make a faster version (upsample) so it fits.

Hi, Vutu on Windows is not ready either, they will come out at the same time.

Sorry for any confusion, we should take it out of the menu.

I plan to make a new model of Soundplane but there's nothing like a timetable for it yet.

Thanks for your interest and meanwhile, enjoy your Linnstrument!

Interesting, I'm always trying to improve compatibility with things like this. thanks for the update.

Glad you're up and running. Enjoy!

hi nate,

I agree this is bad. It will be fixed when the v.2 of all the instruments roll out, hopefully later this year. Thanks for the kind words, and sorry if you lost a patch.


It's what I will be working on immediately after Sumu.

Thanks for sharing. Hopefully we can make sure this all works in the new framework I'm using for Sumu and future instruments. If you want to try it out with Aaltoverb, that should be a good indication!

That's a very fair question but very broad, have you decided what DAW (host) you are using?

(we sorted this out over email)

I have an extra, email me!

Hi 3david3, I would update to 10.14 (Mojave) if you can. It might work on 10.13 but Mojave is the earliest OS version I will be testing.

Thanks so much! Can't wait to get the finished version into your hands.