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