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Update to Latest Airwin
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baconpaul committed Mar 17, 2024
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2 changes: 1 addition & 1 deletion libs/airwindows
Submodule airwindows updated 333 files
21 changes: 21 additions & 0 deletions res/awpdoc/Air3.txt
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# Air3 creates a new form of air-band EQ based on Kalman filtering.

This should be fun :)

Welcome to the experiment zone, once again, with Air3: an air band EQ based on an extension of Kalman filtering, which isn't normally used for audio purposes. As usual, Airwindows is bringing in algorithms that act weirdly because they come out of finance or science. In this case, it's science.

What's Kalman filtering? You'll be hearing more about it, but it's a method of trying to bring accuracy out of noisy data by projecting what the real data might be, and then incorporating sensor readings based on how closely they correspond to the projection. The key idea there is 'based on', because Kalman is all about willingness to throw out bad data and try and zero in on what's really happening.

Of course, in audio, it's ALL real. There's nothing to throw out, it's all legit. Give Air3 some audio, and it begins to do its analysis and projections based on something that doesn't exist: a hypothetical underlying sound, upon which your real-world cymbal sparkle or voice breathiness are just 'noise' to be removed. It's not even based on frequencies, it's trying to chart out a 'real' sound based on what's already a real sound.

What happens? For one, you get a rolled-off sound that is very, very convincing. It's easy to believe the sound was just that way to start with. You don't get a sense of brightness reduction, it just sounds natural. Air3 is shunting off the whole air band to a separate control, and what it leaves behind is very plausible and doesn't sound filtered. Great for reduction of tizz, glare and detail.

And then you take that redirected air band, bring it back in, and crank it up five times as loud, and Air3 comes alive.

I've not heard a better EQ for this super-high stuff. It seems really good at lighting up any audio you send through it. Bear in mind that much like both Air and Air2 before it, this is not an EQ in the normal sense at all. Air and Air2 used the algorithms I also put in Energy, and what Air3 does has more in common with DeBess or Acceleration than it does an EQ. It's going way into concepts of measuring the rate of change of the rate of change and trying to project that onto expected future samples… it's got a large amount of boost on tap, but can be a bit unpredictable. If you simply cut the Gnd control (for Ground) you get just whatever air there was, if you cut the Air control you remove it, but if you boost the Air control lots and cut Gnd, you get another sound from the sheer intensity of boosting being done.

I think this is going to be hard to beat for this purpose, especially used subtly, and expect to be including it into upcoming stuff that doesn't have to act like 'an EQ'. Still a lot of 'lettered' Console versions that need to be made, to emulate analog gear. This one's for imagining where we can go after that, for a new sort of mixing in the box that doesn't follow the constrictions of analog gear, letting you dial in tone characteristics as much as frequencies.

For now, enjoy Air3, and if you've got opinions on what needs to follow it next, drop by a livestream: you have Air3 today because a livestream viewer asked for it to come out ASAP, and here we are. There's lots more. I'll keep working on all this stuff, it's great to see it all come together :)


17 changes: 17 additions & 0 deletions res/awpdoc/Overheads.txt
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# Overheads is for compressing only part of the sound, strangely!

I could say this was a compressor for putting on drum overheads to take out the drums and leave only the cymbals, but that would only be scratching the surface…

Overheads is one of those old Airwindows plugins built on really strange ideas. Let's assume we want to compress drums but leave cymbals. How might we do that? We could filter, but why would we do that when we could do something more perverse? Instead, let's take a really short delay, like a flange. Next, invert it: compression gets driven by the source audio minus the delayed. Then expand the delay. Then what?

Then, high frequencies tend to slip through the cracks between the delay gap. They don't get affected as strongly. But deeper frequencies will produce one part louder than the other, and subtracting produces an output that can kick in the compression. Except it might not, because the sounds might not line up. So add a control called 'Node' to move the delay gap. But how do you know what to do with 'node'? Best change it to something else: 'Sharp', for instance (which is what happened). Then what?

So, put 'Sharp' in the middle somewhere. Start cranking up Compr to compress it, and you'll hear the sound squish, then negate: an area in the sound will dynamically invert, as if you're deleting the snare or kick or whatever, but it will be weird. Move 'Sharp' around to adjust it: larger 'Sharp' should let it grab slightly deeper sounds, smaller 'Sharp' shifts the cancellation up a little. Push 'Compr' further to hear what it does. To actually use it for its intended purpose, back it off so you're only slightly clamping down the drums and leaving the cymbals, making space for spot mics. It'll mess with the cymbals: see if you like how that works.

Or: do whatever go nuts, do crimes, ruin everything. Put it on every drum and set them all differently. Get a really bizarre sound that's not like anything else, live long, prosper. (if you do, join my Patreon!)

No promises.

Oh, also, as seen in the video, if you use this on a sine wave at just the right level, it will turn the sine wave into a triangle. I totally didn't mean for it to do that, and am not really sure how it manages it. Beware. Have fun :)


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