Deimos - free synthesizer (Windows, MacOS, Linux)

[Tom Trnk]

(edited on November 23 2025- added MacOS support)
(edited on December 7 2025 - added Linux support and AU support for MacOS)
(edited on April 15 2026 - added polyphonic expression support)
(edited on May 4 2026 - added Linux VST3 version)
Current version: 0.12.0

Hello!

I'm happy to announce that my free synthesizer "Deimos" (formerly known as "Luna") now has a beta version available.

It is designed to be compact, quick and easy to use, with a focus on sound quality and its own character. I imagine anyone familiar with VA synths should feel right at home with it.
It intends to go a bit beyond typical VA synth capabilities though, offering more waveforms, some phase distortion/modulation capabilities, and flexible modulation.



You can download it here: https://tom-trnk.itch.io/deimos
Currently available plugin formats:
Windows: CLAP, VST3
MacOS: CLAP, VST3, AU
Linux: CLAP, VST3

Please note that it's beta software still, so it may contain bugs or not work properly on your system. It also comes without manual at this point.

I'd be delighted to hear whatever feedback or questions you have, feel free to share it here, on the itch page, or even DM me directly. I'm happy to help with any issues!

For transparency: I'm also working on a bigger and much more capable synth built on the same tech, which I hope to release commercially in the future. If you enjoy this free one, it may be of interest to you too .. in any case, whatever support I can get will be highly appreciated!

Enjoy!
Tom

[MillerSam]

Looks nice. Please prioritize macOS support before Linux as there are more macOS users than Linux but always great to see synths with Linux

[Danilo Villanova]

Thanks, sounds good.

[arturrembe]

Looks very interesting and I'd love to test it more, but the current 1.0.0 Beta 2 is extremely laggy, both the CLAP and VST3 versions.

[ZonderP]

Yes looks interesting, but:
I also would have liked to toy around with it more, but for me the GUI goes crazy - both CLAP and VST3.
Too crazy to be able to seriously try it out. Hard to describe, but seems at least there is something seriously wrong with redraw when it should be done. Also most of the time turning a knob hides the mouse cursor and often I don't see the knob turn.
The 'readout' overlays are sometimes here and placed properly, but most of the time they are either not shown at all or only a quarter of them is visible or they are displayed at some strange position.
And mostly it doesn't draw the red border around a control when I would suspect it should.
Below an example screenshot.

Luna.PNG

But might only be me, because I'm on Windows 7.

That said, both VST3 and CLAP loaded instantly in 2 different hosts without problems and in both it produced sounds.
BTW: When I first was about to write this post, I wanted to try to reproduce one of the strange behaviors and out of nothing my machine just rebooted (no bluescreen, just a complete reboot).
Usually doesn't happen, but not 100% sure if related to Luna or the DAW used within (MuLab 10.0.64 trial version), though when it happened I didn't run much except my browser and MuLab with Luna and moved some knob in Luna.
Edit:
Is it built with JUCE?

[Korg Supporter]

I absolutely love how it sounds for a free synth. The filter is kind of Roland-esque, and this synth replaces my desire to have a TAL J-8 again. Hell, I think it comes close to the u-He and G-Force stuff, and it uses a reasonable amount of CPU. I see it as a sort of spiritual successor to Invader 2. It could really benefit from ring modulation, a sub oscillator, and a second LFO. And I would love to have wavetables/lofi waveforms and filter FM in the commercial version.

[jules99]

So, the question is: does Luna, the plugin, run in Luna, the DAW?

[Nug Wrangler]

Looks interesting.

[Tom Trnk]

I also would have liked to toy around with it more, but for me the GUI goes crazy - both CLAP and VST3.
<.. snip ..>
But might only be me, because I'm on Windows 7.

Maybe Windows 7 isn't even the problem, but I take it as a hint that your graphics card might be a bit dated too. That could also limit your ability to update graphics card drivers, which would be my first instinct in such a situation ..
However, there might be a better solution anyway.

The plugin is built on the iPlug2 framework and is currently set to use GPU accelerated rendering. I'm looking into using CPU based rendering instead to get better compatibility .. looks promising so far except for a few things that get slightly messed up.

Looks very interesting and I'd love to test it more, but the current 1.0.0 Beta 2 is extremely laggy, both the CLAP and VST3 versions.

I assume it was the user interface that was laggy?
I'm aware of a few minor inefficiencies in the UI code and identified one that could potentially compound over time, especially on some slower systems - that will absolutely be fixed.

I'm looking into these two issues now, will update when I have new builds ready!

[Tom Trnk]

I absolutely love how it sounds for a free synth. The filter is kind of Roland-esque, and this synth replaces my desire to have a TAL J-8 again. Hell, I think it comes close to the u-He and G-Force stuff, and it uses a reasonable amount of CPU. I see it as a sort of spiritual successor to Invader 2. It could really benefit from ring modulation, a sub oscillator, and a second LFO. And I would love to have wavetables/lofi waveforms and filter FM in the commercial version.

Thank you so much! Great sound at reasonable CPU is what I was going for, I'm really glad to hear it's working out.
Some of the features you mention will be there in the commercial version (rm, filter fm, second lfo, ..), and then some more. Wavetables didn't make it into the design though .. the idea was to have enough other interesting stuff instead. But more details on that once the time is right

Looks nice. Please prioritize macOS support before Linux as there are more macOS users than Linux but always great to see synths with Linux

Thanks!
macOS is of course on the list as well, but will need a bit of extra work to get the CPU optimizations going on the ARM processors. On the other hand the Linux version involves some uncertainties as well, so I can't really give any guarantees about what comes first or when.

So, the question is: does Luna, the plugin, run in Luna, the DAW?

It might just work. Or it might make our universe implode. Only one way to find out!

[Tom Trnk]

New version 1.0.0-beta.3 is now available.
It has a fix for a potential UI performance problem I was able to identify.
It now also comes with alternative binaries of the plugin that use cpu-based rendering for compatibility, which might get it to work on some older machines as well.

Let's hope that helps, enjoy!
Tom

[ZonderP]

New version 1.0.0-beta.3 is now available.
It has a fix for a potential UI performance problem I was able to identify.
It now also comes with alternative binaries of the plugin that use cpu-based rendering for compatibility, which might get it to work on some older machines as well.

Let's hope that helps, enjoy!
Tom

The '-cpu' versions indeed solved all the issues I've seen - at least in a quick test!
The mouse cursor still disappears when I click on a knob to turn it, but now since the knob updates itself and the readout above it shows the actual value, I couldn't care less!
Looking forward now to spend a few hours with Luna and see what sounds can be squeezed out of it!
Thanks for the quick fix!

[Jonathan Shepherd]

Had a quick go with it and I quite like it! Nice sound regardless of whatever modulation craziness I threw at it. Just remember users, right click(on whatever) is your best friend to get that modulation. I'll definitely buy it when it's out.
PS Good on you hosting this on Itch. io, a great space for independent minds.

[akira2]

New version 1.0.0-beta.3 is now available.
It has a fix for a potential UI performance problem I was able to identify.
It now also comes with alternative binaries of the plugin that use cpu-based rendering for compatibility, which might get it to work on some older machines as well.

Let's hope that helps, enjoy!
Tom

do you plan to add some presets ?

[Matt67]

The name is a bit unfortunate. When I search for Luna and VST on the web, I only find Universal Audio's Luna DAW.