Looking for a microtonal synth...

[brewt]

The old Virsyn synths (which are on their xmas sale as of today) of Cube and Poseidon are large-scale additive resynthesis systems that support Scala, at least on desktop. Not so much on iPad. The Scala implementation is not exactly intuitive (one has to land properly named target tuning files in a specific directory), but it does have the advantage that once you have it set up, it's just there, and you don't have to do anything else when you come back to things. (It does not change on the fly too easily by that same token). Boatload of partials on those, so the quality is pretty darn acceptable.
I'm a little fuzzy as to whether or not they will re-pitch the harmonic series along a different set of numbers, or allow you to control arbitrary non-harmonic partials. For that, I think you need something like Andy Bridle's Adsyn7 software---to render a file off-line, to import into another synth---which has disappointingly vanished. It's the only thing I have found that could do that outside of csound or PureData. Although, with all those solutions, you do have to do it all the hard way: coding, partial by partial, moment-by-moment. Everything you can control, you must control. No macro-like dynamic control, unless you are a cleverer programmer than I; wouldn't be saying much.
Image Line's Harmor also works with scala files. Sorta. I had to monkey with the default structured scala output file to get it to work correctly (by removing all kinds of extra blank lines, and even the octave marker to make 15-tet work).
If software developers wanted to provide a good update and implement full Scala support to their existing softwares, like Dune, Arturia, Rob Papen, DiscoDSP, etc, that wouldn't hurt my feelings. I'm sure that doing so is harder than I would like it to be.
Oh, uh, let's see, Falcon supports Scala too. Reasonably seamless, just not on top. There's a lot of things already mentioned that will work with Scala, including Chromaphone 2, and even some scriptings in Kontakt, which allow for some interesting possibilities, but overall, it is, unfortunately, not any kind of universal yet.

[aMUSEd]

The best support for microtuning is Pianoteq as it supports keyboard mapping (KBM files) too (which is left out of most other microtuning implementations but is really essential)

[Michael L]

Aaron Hunt is a microtonal guru. He makes microtonal hardware and software products including Microsynth:
https://hpi.zentral.zone/microsynth

Microsynth.png

[jancivil]

As long as you determine it in cents, Absynth allows you to create tunings, and you may exceed the octave. It comes with several built in, but they are at fundamental = C, eg., 'Overtone' is from the bottom C.

[goldenhelix]

Probably not what you're looking for but I figured it's worth mentioning that Full Bucket's FB-3200 lets you tune each note of the chromatic scale to the cent, with a range up or down a semitone. You are obviously stuck with 12 notes per octave, but if all you want to do is play alternatively tuned scales and not experiment with extra notes, this might be an easy-to-use option (it sounds pretty good too).

[Dee.P.Tree]

I would like to add to comment of goldenhelix.

Full Bucket's FB-3200 is one of the three soft synths inspired from original Korg hardware. Other two are FB-3100 and FB-3300 (original ones are Korg PS-3100, PS-3200, PS-3300). They feature 12 note microtuning in cents. Easy on CPU, good sounding and free. Best of luck.

[BipTunia]

Still looking?
I've made a few free microtonal VST synths, and one microtonal sampler, here:
https://biptunia.com/?page_id=2070

[cantaloupe]

The recently open sourced Vember Audio Surge is good for microtonality now. TAL Sampler is also great.

Other interesting choices: chipsynth MD, Bazille, Pianoteq.

[discoDSP]

Corona can do microtonal.

Screenshot 2020-03-04 at 12.05.45.png

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[monomaker]

Corona can do microtonal.[/url]

That implementation gives 12 EDO octave retuning only, it can't provide what the OP was requesting (minimising the dissonant curve via 10 TET). Imagine trying to make music with other software and Corona using your implementation - you'd spend all day manually retuning each instance. This is why lockable MTS/TUN/SCL+KBM support is so important, it provides a way to retune the synth quickly and once setup it remains in tune with everything else.

As the previous poster pointed out, Surge is far better for this sort of thing now and free.

[discoDSP]

That implementation gives 12 EDO octave retuning only, it can't provide what the OP was requesting (minimising the dissonant curve via 10 TET). Imagine trying to make music with other software and Corona using your implementation - you'd spend all day manually retuning each instance. This is why lockable MTS/TUN/SCL+KBM support is so important, it provides a way to retune the synth quickly and once setup it remains in tune with everything else.

Yep, it's not that sophisticated. Custom tuning in Corona can be locked across all presets using the lock button.

[empphryio]

I really hope the OP isn't still looking 3 years later. Anyway here's a comprehensive list:

https://en.xen.wiki/w/List_of_Microtona ... s#The_list

And sevish scale workshop is easier to use than scala. U-he probably sounds the best.

[CrystalWizard]

https://en.xen.wiki/w/List_of_Microtona ... s#The_list

Since when is Absynth a “modular subtractive” synth?

[Full Bucket]

ModulAir offers full Scala and TUN support.
https://fullbucket.de/music/modulair.html

Cheers, Björn