ForumsSoftware ← Aalto microtuning accuracy

today I used Aalto as reference to determine the pitchbend range for my Kenton USB MIDI/CV interface, and it was very difficult, rather impossible to find the right setting.

MIDI keyboard -> Aalto with initial preset (no modulations)
MIDI keyboard -> Scala Relayer -> Kenton -> VCO

It turns out Aalto is slightly off between C# and H when using .scl files, because after a while I used Diva as reference, and could immediately determine the Kenton pitchbend range of 2 semitones. Diva, the VCO, and later FM8, lined up perfectly. When played at the same time there were only slow beatings for a note or two. Aalto was the only one that created heavy beatings, so it is clear to me that Aalto's tuning system is not quite correct.

I used sine waves and the identical .scl file (dorian_schl) for all synths (except FM8 which I tuned by ear). The VCO is a Furtherrr Generator which is a very stable analogue oscillator with perfect scaling over many octaves. So I'm sure I eliminated all possible error sources.

I've used microtunings a lot with Aalto, but this is the first time I discovered this error.

Not a big problem, only a detail. I just thought I'd mention it after discovering. When Virta is released, maybe you'll find some time to replicate this behavior, and have a look what could be the reason. No hurry at all.

There is some drift added to Aalto's oscillators so they don't lock up in a polyphonic sound. In the future this could possibly be an optional feature.

ah, that's the explanation. One of those famous "it's not a bug, it's a feature" cases. Yes I think it would be good to have a checkbox in the settings to switch oscillator drift off, for those cases when you need precise pitches. Besides, Diva has an extensive set of trimmers, with detune, drift, variance, etc.


today I compared three softsynths, Aalto, Z3TA, and Diva. With 12-tone tunings, Z3TA and Diva correlate (as well as Scala Relayer and analogue VCO). Aalto does not. But I don't think it is some kind of oscillator drift. And I used a patch with one voice (no polyphony). The only logical conclusion is that Aalto does not interpret the tuning file correctly.

However, when I try non-12-tone tunings, all synths spread apart, no correlation except for the one reference note. I have no idea why is that. Tuning synths together is a very difficult task!

Thanks for the feedback. I'm doing some work on timing issues across all the plugins soon. I will investigate tuning as well. I have noticed that some scales are not loading properly.

Hi, Im interested in experimenting other tuning systems, a very unexplored field. Obviously Im aware of Harry Partch and the avant garde composers of 20th century music(everybody from Stockausen to La Monte Young), but in less academic circles only Wendy Carlos comes to mind.
But now Im reading this post and Im not sure if I can trust Aalto for this particular thing, these problems are a minor detail or is not recommended to even start exploring other tunings in with aalto (hope not!)?
By the bay, could you recommend non academic music that makes uses of different tuning systems?

By the bay, could you recommend non academic music that makes uses of different >>tuning systems?

@juan, sorry I missed your post until now! Aalto was designed to make it easy to explore scales and lots of people have done this with it for years, so you should be OK. If any problems have come up i'll fix them, it's part of the process.

My most favorite composer that uses alternate tunings is probably Terry Riley. I don't think of La Monte Young as "academic" either.

Excited about the new updates. Did you get a chance to look at these tuning issues?

I think what the original poster is referring to may just be the oscillator drift. I can investigate more after this release.

Thanks Randy - no hurry.

my observations concern only multi-instrumental situations, where Aalso is one of those instruments.

If one uses Aalso only, there are of course no problems.

Hey, new user of Aalto and Kaivo, and it doesn't seem like the issues were ever fixed - I have found blatant examples of Aalto and Kaivo not interpreting scala files correctly, especially when it comes to Just Intonation.

As an example, try the scala files found here in the Eikosany folder - compare the results you get from loading, for example, the scale called "Dekany 3 5 7 9 11" to results from another microtonal VST (for example, Vital), and you'll find the results are completely different, and actually out of tune.

Considering I bought Aalto and Kaivo specifically for making microtonal music, this is a major disappointment, as it means I not only cannot trust them when used together with other microtonal VSTs, but I also cannot trust them to even interpret the tuning files correctly.

Really hoping this gets addressed :(

Hey, after a lot of troubleshooting with Randy (thanks again for your responsiveness!), I've found the source of all the confusion regarding how Aalto/Kaivo microtune.

I'll spare the details and jump to the conclusion - as it currently is, Aalto/Kaivo aren't following the "official" standard of how to tune a .scl file in absence of a matching .kbm file. Essentially, the main "issue" is that Aalto/Kaivo are starting with "A4" as the "root note" of the scale, whereas the official standard is to start from "C4". They are also basing the tuning of the scale on making A4=440, when the "official default" method is to tune C4=261.625565 instead.

I've let Randy know about this, but in the meantime, you can easily adjust the behavior to match your other plugins by using a .kbm file with the same name as your .scl file - the important part of the .kbm file is here:

! Middle note where the first entry of the mapping is mapped to:
! Reference note for which frequency is given:
! Frequency to tune the above note to

If you use the above in your matching .kbm file, these plugins should be "in tune".

I hope this helps anyone in the same boat I was :)