Airwindows

FastDistance

TL;DW: FastDistance is a sort of ultra-efficient lowpass filter.

FastDistance.zip (545k) standalone(AU, VST2)
FastDistance in Airwindows Consolidated under ‘Filter’ (CLAP, AU, VST3, LV2)

This is work I’m doing in efforts to help the Godot game engine. Whether or not it’s accepted by them, you get to have it now :)

The idea of the distance filter is, something you can have on every sound source in a scene. It’s gotta be efficient, because there can be an awful lot of them. It’s gotta handle wild modulations, because who knows what might be happening there in the game engine. And it’s gotta roll off high frequencies, because stuff that’s far away doesn’t sound as bright as stuff that’s right next to you.

Ideally (like with my previous Distance plugins) it’s doing clever things to put across the sense of great distance, but how clever can you be if you might have to have hundreds of sound-makers all talking at once? And so, FastDistance specifically chooses forms of treble-filtering that are dirt simple. It’s just a variation on an averaging filter crossed with an IIR. Need more? Layer on more of them. The IIR (infinite impulse response) is not there to be fancy, it’s just there because it saves me allocating one extra variable. The way it uses more or less poles of filtering is literally jumping into a pile of them and letting them go. There’s no way of controlling it other than just choosing how deeply you filter in this one particular way that’s unreasonably efficient to calculate. In fact you don’t ‘calculate’ it at all, you just use it directly.

The weird thing is it actually sounds pretty awesome.

Since it’s so efficient to run, instead of doing three or four poles of filtering, you can do thirty or forty. They run about as quick as calculating the coefficients of a regular old filter. There’s next to nothing to them. And when you take such a primitive filter and just do it more, what you get is increased cutoff steepness… but the cutoff is very high already, and it’s not at all resonant. So the intense layering just gives you a very natural sounding darkening effect, combined with taking the highs and absolutely burying them an unthinkable number of dB down. It’s just how it works. It’s not really a ‘steep cutoff’ no matter how many poles you use, and is never the least bit resonant or filter-sweepy. Just a distance through air darkener.

It’s very likely that this will find other use but for now I’m gonna see if Godot likes it (and if it’s competitive efficiency wise with the more traditional low shelf they’re using). I’m working on a system for game engine reverb that I hope will be useful, also for Godot, and I’ll have an ultra lightweight reverb soon that’s teaching me many useful things I can incorporate into my flagship reverbs.

And whatever else happens with all that, you have FastDistance as a free plugin, plus also as MIT licensed source code that you can use for anything so long as you credit. Enjoy the new lowpass :)

Airwindows Consolidated Download
Most recent VCV Rack Module
download 64 Bit Windows VSTs.zip
download Signed M1/Intel Mac AUs.dmg
download Signed M1/Intel Mac VSTs.dmg
download LinuxVSTs.zip for x86
download Pi4VSTs.zip for 32-bit Pi
download Pi5VSTs.zip for 64-bit Pi
download Retro 32 Bit Windows VSTs.zip
download Retro PPC/32/64 Mac AUs.zip
download Retro PPC/32/64 Mac VSTs.zip
Mediafire Backup of all downloads
All this is free and open source under the MIT license, brought to you by my Patreon.

Date September 6, 2026
Author Chris
Comments No Comments

PurestWarm3

TL;DW: PurestWarm3 is a subtle tone shaper and warmth adder.

PurestWarm3.zip (503k) standalone(AU, VST2)
PurestWarm3 in Airwindows Consolidated under ‘Subtlety’ (CLAP, AU, VST3, LV2)

It’s been some years since PurestWarm saw any attention. It’s always been a bit tricky: proper second harmonic distortion is ‘warmth’ but it’s very hard to hear. But that’s just the start of it…

Every version of PurestWarm ever (OK, so that’s just the original and v2) has had a flaw that I didn’t fully understand in 2022, and have come to respect. Freya Holmer’s video on spline continuity tipped me off, but I learned about it years earlier with an ill-fated Channel ‘upgrade’ that I had to roll back as if it was ‘New Coke’. People respond to sudden changes in derivatives even when the waveform seems to have perfectly good continuity.

The crossover through zero in an audio waveform counts.

So, the previous versions of PurestWarm do an abrupt switch between ‘dry’ and ‘effect’ at the zero cross. That’s nearly as bad as what a sine does (abruptly changing from positive to negative curvature at zero) and even though it’s fairly hard to hear the largely even harmonics this produces, it’s still a limited approach. And so, PurestWarm3 is here… but what’s it doing that’s different?

An odd little use of ‘FMA’ (fused multiply-add) to produce a super high resolution version of a continuous asymmetrical distortion. One that can scale up and down to produce more or less of an effect. One that’s already been heard in RetroBass, in ChannelX… now you’ve got it standalone, in a stripped-down and minimal plugin that only does that one thing.

And it’s so much purer and smoother than even the previous two, that you damn near can’t hear it at all.

That’s the trouble with these. PurestWarm3 actually throws two harmonics, a second and a fourth. It doesn’t matter much, you still can barely hear it. I’ve set it up so it can be exaggerated wildly, just to be heard. The challenge there (not present with the previous two) is, this is a continuous algorithm. It just reshapes everything. So what it takes from one side of the wave, it adds as peakiness to the other side, and so it will distort enthusiastically if you push it too hard, and then if you don’t push it too hard you kinda can’t hear what it’s doing, much.

Add to that the same derivative BIP tech I’ve been developing, and it really really stays out of the way sonically. A puzzle.

So, this is not really a ‘slather on thicc warmth!’ effect. If you have sounds that are already asymmetrical, such as certain basses, it can reshape those to ironically make them LESS warm but cleaner. Or, you can exaggerate the effect and make it more striking. Push it too far and you’re messing with a kind of expansion that won’t play nicely with mixing.

I hope to make use of this in a future console plugin where it’ll convey the exaggerated transient spikes of certain late-70s noise reduction, so it’s not like there’s no use for it. Just don’t expect an ‘EQ-like’ activity out of PurestWarm. It is rearranging energy, almost losslessly, to be a subtly different shape, and leaving next to no trace it was ever there. To some of you, this might be of great interest if that got your attention…

Airwindows Consolidated Download
Most recent VCV Rack Module
download 64 Bit Windows VSTs.zip
download Signed M1/Intel Mac AUs.dmg
download Signed M1/Intel Mac VSTs.dmg
download LinuxVSTs.zip for x86
download Pi4VSTs.zip for 32-bit Pi
download Pi5VSTs.zip for 64-bit Pi
download Retro 32 Bit Windows VSTs.zip
download Retro PPC/32/64 Mac AUs.zip
download Retro PPC/32/64 Mac VSTs.zip
Mediafire Backup of all downloads
All this is free and open source under the MIT license, brought to you by my Patreon.

Date August 30, 2026
Author Chris
Comments 3 Comments

ChannelX

TL;DW: ChannelX translates Channel9 into a profusion of wild experiments.

ChannelX.zip (545k) standalone(AU, VST2)
ChannelX in Airwindows Consolidated under ‘Tone Color’ (CLAP, AU, VST3, LV2)

Everything’s the same, and nothing is the same.

It’s quite hard to tell what will happen with this plugin update. To surface appearances it’s exactly the same as Console9, right down to the slightly odd choices like a (lower slope) interleaved IIR filter for highpassing. The controls and what they do are exactly the same. It still has named ‘modes’ it operates in, still has a drive control that produces the Spiral saturator at 100% and Density at 200% and crossfades from dry to Spiral to Density, linearly. This is what Channel9 has had since 2021.

It’s not 2021 anymore… and Chris from Airwindows has been responding to the pressure of vibecode guys flooding the plugin market by trying new stuff more often… based on the existing Airwindows codebase, and pretty much nothing else. And Channel’s number came up. (technically, letter, since X can be used for 10)

Longhand was an experiment in using a Taylor series to make a sine function ‘by hand’ in case building it out of a single, continuous algorithm sounded better than the stock, optimized form. It seemed to sound nice. Both the sine part, and the Spiral part of ChannelX are now made that way, longhand, at very high precision.

RetroBass came out just last week! It involves modulating even harmonics into the sound. ChannelX now includes this in its highpasses, but still uses the dielectric modulation from Capacitor, and also still uses interleaved filters, which RetroBass does NOT use.

A stack of other plugins are being updated with an experiment I did inspired by elliptic BLEP antialiasing! But where that is established as a way to flawlessly synthesize a filtered result to any degree of high-order filter ripple, my experiments veered off to produce a tweak that operates over ONE sample, not to delete aliasing but to doctor it in such a way that high frequencies remain locked in place and do not ‘come forward’ in the way aliased highs seem to do. Totally other thing, seems to work, zero ripple or blur or SRC-like qualities. The directness is incredible. (people don’t seem to go for this quality very often in 2026, which might be as good a reason as any to pursue it)

So ChannelX is a wild mix of very new experiments under a familiar surface. There have been times I freaked out over how good it sounded compared to Channel9. With a bit of luck this bodes well for new plugins coming up. We shall see.

Airwindows Consolidated Download
Most recent VCV Rack Module
download 64 Bit Windows VSTs.zip
download Signed M1/Intel Mac AUs.dmg
download Signed M1/Intel Mac VSTs.dmg
download LinuxVSTs.zip for x86
download Pi4VSTs.zip for 32-bit Pi
download Pi5VSTs.zip for 64-bit Pi
download Retro 32 Bit Windows VSTs.zip
download Retro PPC/32/64 Mac AUs.zip
download Retro PPC/32/64 Mac VSTs.zip
Mediafire Backup of all downloads
All this is free and open source under the MIT license, brought to you by my Patreon.

Date August 23, 2026
Author Chris
Comments 1 Comment

RetroBass

TL;DW: RetroBass is a special kind of highpass.

RetroBass.zip (509k) standalone(AU, VST2)
RetroBass in Airwindows Consolidated under ‘Filter’ (CLAP, AU, VST3, LV2)

It started with a second-and-fourth-harmonic generator I stumbled into (never fear, you’ll get that too). Though it was a little more complex than the simplest second harmonic generators, it still had the unmistakable signs of them: you could mess with the settings until the output clipped like mad and still you’d not really hear what it was doing. The asymmetry has tone qualities, is warm and all, but at such low harmonics it’s just so hard to hear.

Causing me to wonder: can you use that to take away low frequencies like a filter?

So, combining it with a simpler version of the highpass filter I use in Channel, I start experimenting (on a livestream) by modulating it with the same IIR stuff I’m subtracting to make the highpass. Not only that, this asymmetrical even-harmonics thing is using the aliasing-manipulation hack I came up with for normal distortions just recently (and that is buck wild because I invented that on purely hard clipping, but it generalizes) and the next thing you know I’m figuring out whether it’s best to bring it in directly, or inverted.

And I observe that it produces this funny double bump of a distortion, but one way around the initial lobe of what was once a sine wave normalized to 1.0, is bigger, and what follows is both smaller and a tighter shape. It’s acting like it’s taking energy in the oscillating wave, and running out mid-oscillation. This is what analog circuits do, when their coupling capacitors run out of steam. It’s just being done in a peculiar way.

And dialing it in using the test waves, and then trying it out on lots of different things… I discover that it’s RetroBass. It’s better than anything else I’ve had, for specifically making stuff bass-starved in a retro-seeming way. It sounds like old gear not designed for modern subs.

Not only that, if I push it farther, it starts to get into those hot harmonic-rich zones that make some old vocals sound so intense. It’s like a treble zing that is done through weakening the fundamental. Very handy.

RetroBass will continue to be useful in things like retro consoles, but right now it’s a standalone highpass you can use however you like. There’s more to follow (I did mention the aliasing thing designed around hard clipping) but RetroBass leads the way. :)

Airwindows Consolidated Download
Most recent VCV Rack Module
download 64 Bit Windows VSTs.zip
download Signed M1/Intel Mac AUs.dmg
download Signed M1/Intel Mac VSTs.dmg
download LinuxVSTs.zip for x86
download Pi4VSTs.zip for 32-bit Pi
download Pi5VSTs.zip for 64-bit Pi
download Retro 32 Bit Windows VSTs.zip
download Retro PPC/32/64 Mac AUs.zip
download Retro PPC/32/64 Mac VSTs.zip
Mediafire Backup of all downloads
All this is free and open source under the MIT license, brought to you by my Patreon.

Date August 16, 2026
Author Chris
Comments 4 Comments

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