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Airwindows is one guy: me! I am an audio hacker and computer programmer from way back. I seek only to continue my life up here in Vermont, inventing things and putting them onto the internet, sometimes for free and sometimes for pay. My hope is that people richer than me (i.e. most people) don't rob me. My other hope is for another cup of Aeropress. One out of two ain't bad!

Iron Oxide 5

TL;DW: The old school, heavily colored Airwindows tape emulation.

(there is a build of the initial version available: IronOxideInitial5 is the first version, before I added the noise level control. I’m providing it in case people need it for special circumstances, but you should NOT have it and the full Iron Oxide 5 installed at the same time, because they share plugin identities and you’ll confuse your computer)

The legacy of this plugin goes way back. Many years ago, I was coding some of my first AU plugins, and some friends of mine were having bad experiences with a company that sold the big tape emulation plugin of the day. Outraged, I charged into the fray: I would code a replacement for them, one that did the same things and sounded better and sold for $60 (later $50). And that was Iron Oxide. It had one ‘ips’ control, a Drive, and an output level.

Then, I expanded on that with Iron Oxide 2. That one split the ‘ips’ top and bottom cutoffs, so you could vary the ‘bandpassy’ quality it had. It used the same unusual algorithm, but made it more flexible. It also incorporated an unusual sort of anti-aliasing in the form of a ‘tape noise’ factor that blurred slew.

Iron Oxide 3 added flutter. At this point, we stepped away from strictly zero latency: instead, the plugin declares zero latency but produces a fuzzy smear across one or two samples, the range the flutter covers. That persists with Iron Oxide 4 and 5, and is how the current free VST Iron Oxide works.

Iron Oxide 4 added something else that (come to find out) is also present in the Delta Labs Effectron: inv/dry/wet control. That persists with Iron Oxide 5. The way you use it is, set up an Iron Oxide tone that accentuates a frequency range (like mids). Drive it, or leave it clean… but begin setting the control to inv (the inverted position). You’ll subtract it from dry, causing a dip rather than a boost, but if you’re saturating the ‘tape’ then the dip will leave dynamic energy in the area being cancelled: it will cut out fat, leaving punch. Overdrive the ‘tape’ section harder (and turn down ‘inv’) to get more punch out, or leave it clean and use it just to cancel out the area. It’s an unusual effect, but it works.

Iron Oxide 5 is all of this, plus lessons from the ‘Purest’ line of plugins (mostly still in line to be released later) to produce the same thing as Iron Oxide 4, but even more pure and resonant and intense. None of these are really ‘mix buss’ plugins (though I’m not the boss of you): they’re far too intensely colored and distorted. They’re more about ‘make that snare really bark’ and so on. Though of course, since I’m not the boss of you, I can’t prevent you from trying to use it on the full mix. All I can do is say that ToTape is coming, and that’s the MODERN tape emulation. This is the old school, rowdy, obvious tape emulation, full of grunge and bark :)

And it is free, because it’s supported by Patreon. We’ve passed the threshold where I’m releasing the formerly-Kagi ‘greatest hits’ plugins, and as long as I stay over $600 a month, that continues. If I top $800 I begin open sourcing the plugins too, and if I top $1000 a month I’ll be releasing two of these greatest hits a month, in addition to other plugins and related plugins and YouTube videos showing you how to do things.

A splendid time is guaranteed for all, and I hope you enjoy Iron Oxide 5. Stay tuned for ‘TapeDust’, the ‘analog tape grain’ aspect of Iron Oxide isolated and put under your control so you can have it separate from the complete plugin (i.e. no overdrive or distortion), and I am open to also doing an ‘Iron Oxide Classic’ which goes right back to Version 1 and acts like the much simpler distorted bandpassy emulation where it all began. Ask and you shall receive :)

Swappable Mega Dark Hat

Here’s another Airwindows studio post that serves two purposes. One, I’m showing you an alternate mega-dark and loud hi-hat sound (like the acoustic version of a low-fi sampled dark hat) you can make with a $50 Wuhan cymbal and some tin-snips. But it was also an experiment to see if the Xiaomi Yi camera compresses its microphone. It does not! So this is what THAT sounds like, and also this serves as a YouTube reference. The drum parts are completely smashed to hell, and YouTube is getting the raw cam footage directly. So, this will show you what YouTube is currently doing with heavily distorted audio. If they pad this, then they’re in ‘normalization mode’ and will also turn down over-loud masters. If they leave it, then they’ll accept at least brief ultra-loud content. Refer back to this video if YouTube experiments with how they transcode stuff, to see if it changes!

This is supported by Patreon :)


TL:DW; A different bright EQ from any other.


Digital EQ is a series of trade-offs. You can have a general effect with a simple calculation, or a more complicated effect with more calculation, or you can just bury the audio in calculation and get something very precise which unfortunately is just a huge pile of mathematics. And digital EQ shows this: it’s typically some digital-audio textbook calculations, maybe with distortion or a convolution impulse on top of it. When it does extreme things, like sharp or resonant filters, it bogs down in the details and loses texture, and it’s a rare developer (like Andy Simper with his nifty ‘The Drop’) who can do something interesting with ’em.

Enter Airwindows.

These are something different. They’re ‘air band’ boosts (less effective as cuts, or you can over-cut to create odd cancellation effects) based on an entirely different principle, basically interacting with the sample rate directly as if it was a ‘gearbox’. There’s a feedback parameter that serves to increase the resonance of the filter, making it ring and produce still another tonality.

The thing is, you don’t get to adjust them. I can’t give you 14K out of the 15K tap, and that number only relates to if you’re at 44.1K sampling rate: if you’re at 48K it’s actually boosting 16.3K. This is the technology that turned into ‘Energy’ (a forthcoming Kagi-class plugin on the ‘patreon release list’, and it can’t be adjusted: it’s a little black box and we’re only doing a dry/wet with each tap (the Filter Q affects all taps).

But what it CAN do is give you a ridiculously powerful boost at 10K, 15K or 22K, and let you sharpen it. It’s doing that with far less processing than you’d usually have to do, to get the result, and it’s doing it as a simple add so it retains the tone of the audio. And one more thing: if you do a super-sharp resonance, with normal EQ that’s linear phase you have to produce extensive pre-ring to get that filter curve. Air doesn’t do that. All its ring takes place after the initial transient attack, so Air is unusually good at sculpting the attacks of trebly sounds… for instance, EDM high percussion and hihats and sampled cymbals… and doesn’t blur where they attack, at all.

That makes Air a VERY good secret weapon for tightening up the percussiveness of hats and snares on EDM. Whatever genre you’re in, you can dial-an-attack and there will be no blurring from the EQ. Your options might be limited to a few bands, but on the other hand you can make crazy blends (they’re parallel) and get unique tonalities all with ultra-sharp attacks, even if you’re maxing out the Filter Q to make things sound very, very unnatural.

Sometimes that might be exactly what’s needed :)

Oh, but please don’t actually treat it like a secret weapon. Treat your SETTINGS like a secret weapon, and tell people if you’re finding Air useful. That’s because I survive through a Patreon that has replaced the previous form of Airwindows, and it’s done so well that now we’re starting to release the greatest hits of Airwindows! If all goes well, Iron Oxide 5 is coming out next week, and you can have the latest version of the second most popular plugin Airwindows ever made, with $27,844 in sales over its lifetime as a $50 plugin. And it will be FREE. And at the next funding goal, I begin the process of also making them open source. So please don’t treat Airwindows plugins as a secret weapon. Treat it as a Patreon, and the more the merrier: it lets me do more interesting things if I can afford to do them :)


TL:DW; Distortion and demolition of air molecules, modeled.


Here’s something rather special. What if you could distort like air molecules distort?

I studied recordings of competitive tractor pulls, of Space Shuttle launches, various recordings that represented the way air can be mangled and break apart. The result is Loud… a step into a much louder world. It’s a distortion that can be slammed to unthinkable ‘heart of a supernova’ dB levels, but can also be subtly introduced to give the sonic coloration of a big LOUD noise in open air. Makes for a very interesting ‘glue’ at zero boost!

Here’s how it’s done: rather than apply a consistent transfer function like a normal distortion, Loud knows whether you’re compressing the air, or letting it rebound. And if it’s snapping back, it can do it with the speed of lightning, but if it’s compressing, the air can be squished to practically solid, increasing heat. This extreme nonlinearity is why Loud sounds the way it does. It can sit on a whole mix to give it scope and authority, or it can be pushed harder on individual tracks like guitars and drums to amp up the ferocity.

Remember, if you’ve got it totally fuzzing out, you are probably already beyond any sound level achievable by human means. The completely fried sound of cranked-up Loud is not meant to seem like acoustic phenomena as we know it. It turns up that loud because I grew up reading Douglas Adams’ “Hitchhiker’s Guide to the Galaxy”, and because in no other way can you accurately emulate a Disaster Area concert. :)

If you like me inventing things like this, support my Patreon. It’s over the funding goal of $600, meaning that I will start to release the Kagi for-pay plugins, one a month, starting with Iron Oxide 5 (the newest version, never seen before!). But there are other goals to reach, too: at $800 I will begin open sourcing these plugins under the MIT license, and at $1000 I will release two of the Kagi plugins a month—twice as fast! Sky’s basically the limit. And for today, as a token of good will, I bring you the loudest noise in the universe :)

Speed-King-Izing Axis Longboards

I’m getting together a huge (18) pile of new plugins to make, including the mighty Iron Oxide 4, and also dealing with a YouTube issue where someone’s tried to copyright strike white noise generated in a ToTape4 video, and trying to fix my porch. But I’ve got time to share some drum pedal experiments with you!

This is how to make Axis longboards ‘feel’ more like Ludwig Speed King pedals, but without the squeaks and vintageness. It’s all about the geometry of the linkages, and works great: you should see right away how this works, and how it’s done. If you have questions, ask! :)

Things are looking good for May to be my first month of releasing the premium, Kagi-era plugins. As long as the Patreon is still over $600 when May begins, we’re good to go, and probably it will stay at least at that level from now on (not like I’m going to stop being Chris from Airwindows or anything ;) )

The next stages of the Patreon are reaching $800 (where I begin open-sourcing what’s been put out already, plus my templates for making all the plugins) and $1000 (where I start putting out the premium plugins TWICE as fast, two a month, on top of everything else I’m releasing). It’s exciting to see where this is going!

Hope the glimpse into lever-hacking (for that’s how you Speed-King-Ize an Axis pedal) was fun! Next one is an alternate hi-hat sound, an unusually good dark LOUD hat for roughly $43 plus a pair of tin-snips. Then the flood of new plugins resumes :)

High Impact

TL:DW; Grit and punch without fatness.


Sometimes it’s all in the name.

High Impact has been one of the Airwindows secret weapons for a long time. It’s a pretty basic idea: know how Density distorts and makes audio huge and fat, and Drive distorts and doesn’t make stuff as fat? High Impact answers the question, ‘what if you could distort and not make things fatter AT ALL’.

This is not EQ I’m talking about, though it can come off like EQ depending on what you feed into it. High Impact combines a distortion and anti-distortion circuit to reshape the transfer function of the audio, as follows: crank it up, and quiet subtle samples aren’t turned up much. Then medium samples are turned up a LOT, and then the loudest samples are distorted and hit a wall past which they can’t go. The result is an obvious distort which doesn’t bloat things. It’s a ‘dial-a-rasp’, or ‘dial-a-slam’ for percussive noises, and though the concept is two different kinds of overdrive combined, it’s an Airwindows plugin so it’s not overprocessed, it’s super raw.

That suits this plugin super well, and that’s why the AU-only High Impact has been a secret weapon for many people for years—and now it’s out for Mac and PC VST.

A word about the ‘secret weapon’ thing: I hate that. Do as I do, and communicate openly. Airwindows plugins are not preset things that you hide somewhere to add magic sauce to your mixes. They require intention, and there’s no one right way to use them: Airwindows plugins are like if a certain mic modeler you can rent that offers ‘silky expensive microphone models’ had just a blank ugly faceplate with just one knob, ‘silky’. And you could use it as a guitar stompbox if you wanted, not even a microphone anymore, and it was no longer connected to a ‘magic gear item’ so you’d have to ask, ‘HOW silky does this sound need to be, in my mix?’ because there was no one right answer.

That’s what Airwindows is like. For High Impact, read ‘raspy’ or ‘mean’ or ‘grindy’, whatever describes the sound for you. Now you’ve got an extra parameter: instead of just bass, treble, loud, soft (or even fat and thin) you’ve got ‘aggro’ on a knob. That can relate to any bit of audio you’re working with… and your ‘secret sauce’ is not the plugin, but your sense of taste (or tastelessness) in using and abusing it. So, don’t keep Airwindows plugins a secret weapon. I hate that. Tell people what you’re using, so I can get more supporters and keep doing all this, on a bigger and bigger scale.

Speaking of which, I have a Patreon milestone! As of a couple days ago, I hit $600 a month, and I’ve recently changed that to be the point where I start releasing the Kagi catalog! Now, people sometimes bail as the first of the month rolls around (and also I don’t get paid quite the full amount shown). So, it’s possible this milestone will go poof as we reach May, in which case we’re still waiting. BUT, if the dust settles and it’s still over $600 going into May, I will put out Iron Oxide 4 (the second most popular plugin I have EVER made) as free AU/VST!

(oh my God, I look so young in that video o_O )

If I’m still over $600 when May begins, you get THAT plugin free. My hope is that, as I reach this stage, people get more of an idea of what’s possible out of my Patreon project. All this time, I’ve been putting out more than 47 plugins entirely from the ‘freebie pile’, and not touching the ones that kept me in business a decade. Now, we start to get into the serious ones, the ones worth $50 to a lot of people. I’ve even drawn up a timeline on the Patreon, showing when each plugin will come out if I stay above $600. (if I clear $1000 they go twice as fast and I’ll revise the timeline accordingly!)

Here’s where things REALLY get interesting. Hang on to your DAWs, because we’re about to go full warp drive :)


TL:DW; Like a highpass on the side channel, except it’s a lowpass.


There are some nice things about Patreon-era Airwindows. Not the money: that sucks, though I think I just about have basic survival taken care of as long as I don’t eat much and nothing happens to my car :)

No, the cool thing is this: I can put out tools that have NOTHING to do with a plugin marketplace. If even one person finds the plugin useful, I can put it out. SideDull is kind of like that. I was asked, ‘since Sidepass is great, can we have a lowpass version?’. And I went ‘huhh? why would anyone want to narrow just top end, or center mids and up while not touching lows?’

The answer is of course ‘why not?’ and ‘if you are sure you won’t be doing that, don’t install this plugin’ :)

I don’t need to explain what SideDull does: it’s the same as Sidepass but in reverse, narrowing/mono-ing highs and down. I WOULD like to explain something about its role in a DAW user’s toolkit, though. I’m seeing this increasing churn in the plugin industry, a frenzy of new stuff and new requirements and DRM systems and dongles and such. It’s like a fulltime job to keep up with your recording system. My own pet fear is updating something only to find that I’ve hosed myself and everything’s now broken.

That’s why SideDull, and every other plugin, is built on a time-capsule 10.6.8 system and the VST’s built on a time-capsule isolated-from-the-internet virtual Windows 7. I’m using the simplest possible interfaces (some vendors, like Blue Cat, have taken pains to implement the generic interface super well, and can even skin it attractively) and not touching stuff that causes forced obsolescence, which I think is really bad news for us all.

So, the free AU/VST plugins (and the Kagi AUs before them) can be like your favorite screwdriver: you get to have the best and simplest audio tools that do NOT break. That also means that if you can only afford legacy computers (or just like being frugal and spending your money on Rickenbackers, as I long to do) you aren’t out in the cold… ever. I’m dedicating the rest of my life to putting tools in the hands of kids and dinosaurs alike, and following it up with my open source initiative. And the longer I do live, the more of it I get to do: but if I keel over tomorrow, all the plugs will still work and I will have had a good day and slept with a clear conscience :)

(and if I do croak, somebody mirror it all! pronto! it’s not all on GitHub yet!)

THERE ARE CHANGES to my Patreon. The tape emulations are closer! I’ve scaled all the goals down to make them more reachable. (remember, I’d like it to be through many people rather than just a few, the goal must remain reached for me to continue doing those rewards!) The new ‘start going through the list one a month’ point is now $600, opensourcing is $800, releasing two a month is $1000 etc. This is added to what I’m already doing, not replacing it: I’ll keep doing the plugins I am doing, you just start to get the ‘greatest hits’ too.

Also, if you missed it: when the release schedule stresses me out, sometimes I turn to game programming. I’ve just put out the mostly-final form of one such game thing, the Minecraft server plugin Snowball Madness. There’s a video and everything, and I have a server up and running this peculiarly anarchic Minecraft variant: it’s at (minecraft 1.11), because sometimes you just need to go somewhere and blow things up with infinite TNT. This is something I keep around, so anyone who’d like to join me and my friends in our occasional building-parties is welcome to learn the ropes (or the snowballs) join, and find some nice secluded spot to homestead. I view it as a longterm anarchy server with a twist (or six), and of course if you’d like to support these researches… which I have to do, to keep from burning out on plugins alone… you can simply support my regular Patreon or direct minecraft-oriented Airwindows fans to do that. Nothing more is needed, this is just another thing I do and have always done :)

Snowball Madness

TL:DW; More Airwindows game research, with source code!

SnowballMadness.jar | GitHub repository

To stay fresh with plugins, I code other things, and it’s become part of my open source initiative. In fact I’m starting off the plugin open source thing by setting up my GitHub page with hobby game projects (first Counterpart, and now Snowball Madness). So you can read the Java code of this plugin, and use it as a framework for your own ideas. A lot of the initial work was done by my brother Dan, who also advocates open source code. Read More


TL:DW; Compressor for accentuating beats and pulses.


What is ‘ballistics’ when it comes to audio gear? It’s the way the gear handles dynamics coming in. It’s the swing of a VU meter that can tell you what your music feels like.

Or, since this is Airwindows and we don’t do no steenkin’ meters, ballistics is the way dynamics hit this compressor to produce outrageous groove.

This is also a good reason to keep me around working on stuff… this plugin wouldn’t exist if not for an earlier free VST plug from me, called SurgeTide. That one controls dynamics by altering the rate of change of the rate of change OF the rate of change of the audio. What, you may ask, would happen if you did that? I’ll tell you: firstly, there is no smoother compressor. It’s utterly, totally fluid and artifact-less, organic to the Nth degree. But, it doesn’t sound like it’s doing anything until suddenly it kicks in and starts making the dynamics swing up wildly to boost every beat. Incredibly hard to control. You really can get a sense of ‘huge surges of the musical tide’ emphasizing the deepest rhythms, but it’s a bear to set up!

And since I’m still out there working on stuff thanks to my Patreon, now there’s a whole new version, so different it counts as a separate compressor: Surge.

Here’s the thing. Compressors are as unique as, say, guitar overdrives. You can search for the magic one, but there can be all different sorts of ‘right one’, with hugely different characters to ’em. I made Pyewacket as a free VST. It delivers a super-articulate attack transient and leans out the sound rather than simply turning it down, and gives a ‘British Classic Rock’ vibe without any silly adding of faux-analog mud: that one clamps down on the body of sounds while leaving tons of intensity and headroom to the tone. Its ‘ballistics’ are very simple and it’s more about delivering a certain kind of attack, and making stuff more even and consistent.

Surge isn’t anything like that. It’s SurgeTide, but easier to control: just bring it up until it starts compressing enough, and don’t go too far to where it inverts the dynamics. You can hear it easily, unlike SurgeTide. But it still retains most of the uncanny fluid organic quality SurgeTide has, and most importantly, it has the ballistics. That means that if you put a pumping, rhythmic mix through it… it will accentuate the beats in a very aggressive way that’s not like anything you’ve heard before. The attacks pop way out, including the deepest bass pulses: this is yet another way to handle compressed bassy mixes and transform them into something punchier. And unlike SurgeTide, it’s very controllable.

You might want to push it hard enough that the dynamics jump way out. You might want to use it as ‘glue’ and hit it only very gently, and take advantage of that extreme fluid openness (a result of the way its control is so abstracted: again, it alters the rate of change of the rate of change OF the rate of change). The one thing it won’t do at all is limiter-like behavior, it’s way too funky for that! So anywhere you need to use a compressor that is just ultimately funky, bouncy, squishy… try Surge. It might be right up your alley.

THERE ARE CHANGES to my Patreon. The tape emulations are closer! I’ve scaled all the goals down to make them more reachable. (remember, I’d like it to be through many people rather than just a few, the goal must remain reached for me to continue doing those rewards!)

The new ‘start going through the list one a month’ is now $600, opensourcing is $800, releasing two a month is $1000 etc. This is added to what I’m already doing, not replacing it: I’ll keep doing the plugins I am doing, you just start to get the ‘greatest hits’ too. Looking forward to entering that phase! (and once those ARE out, I’m free to develop new versions like I’ve done in following SurgeTide with the way more useful Surge).

DC Voltage

TL:DW; Literally control voltages for digital workstations, because why not?


This is exactly what it says on the tin. Do NOT just put this in a mix and crank it up to see what it’ll do. If your whole system is DC-coupled you will blow your woofers, just like that, after a big ‘whump’. I will not take responsibility for damage caused by misusing unusual tools.

What SHOULD you do? Here are some ideas.

There is no DC offset filter nearly as good as applying an opposite offset. Use metering, perhaps option/alt-dragging on the slider if your DAW permits it, to cancel out a DC offset without any sonic penalty at all. This is called a ‘DC servo’, but digitally. If you can get it perfect and then bounce files so you can work with a center corrected section (so you don’t have to get a pop from turning it on or off) this would be the highest quality way to get rid of a FIXED DC offset without altering any of the bass at all. It’ll retain right down to 0.001 hz or whatever, and only kill what is totally unvarying DC.

If you have a converter that’s DC coupled, and analog modular synthesizers, you can use this to create and modulate control voltages. Use it as a voltage source and then mix stuff together using DAW routing much like you use patchcords on your synthesizers, and be careful not to route control voltages to your monitors! I know there are people who’ve done odd things to get DC voltages inside their DAWs. Now it’s a lot simpler :)

This plugin may not be any use to you, and don’t play with it if you don’t know what it is. If it is useful to you, you already know exactly what you’ll do with it, so go right ahead, now you’ve got DAW control voltages out of a simple plugin.

THERE ARE CHANGES to my Patreon. The tape emulations are closer! I’ve scaled all the goals down to make them more reachable. (remember, I’d like it to be through many people rather than just a few, the goal must remain reached for me to continue doing those rewards!)

The new ‘start going through the list one a month’ is now $600, opensourcing is $800, releasing two a month is $1000 etc. This is added to what I’m already doing, not replacing it: I’ll keep doing the plugins I am doing, you just start to get the ‘greatest hits’ too. Looking forward to entering that phase! I feel that more people will recognize the worth of my Patreon if those plugins begin coming out. They are pretty amazing (and once they ARE out, I’m free to develop new versions, opening up my researches even wider).

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