Krotos Reformer Pro Review


Reformer Pro ($238) is the most interesting effects plugin I’ve ever tried. Sure, there are plenty of plugins which can mangle a sound in unrecognizable and unpredictable ways, but this one mangles the input sound in unrecognizable but predictable ways which are easily controlled live.

So, What Is It?

While most effects will use the audio signal on the input as the only sound source and process the input audio through various algorithms, Reformer Pro also has four slots to load four of its libraries. To explain this starting with a simple scenario, let’s say the X-Y pad used to select the library blend is all the way in one of the corners, so only one of the libraries is used (giving you basically what the free Reformer does). On receiving and analyzing input, Reformer Pro plays back the sound from the library which matches the input’s dynamic levels. So, load up the Black Leopard Pro library, and send a quiet piano note to the input, and you get a soft leopard growl. Short notes get short growls, and long notes low growls. Smash a loud note, and you get a roar. Move the X-Y pad somewhere else, and you get a blend of the other loaded data, which can vary from that leopard to polystyrene rubbing noises, or any user data library you create.

It’s sort of like an audio-triggered sampler with a very large number of velocity layers and four slots, but it doesn’t just play back a few sample files – the signal processing it’s doing seems considerably more complicated, as it can easily use more than 30% of the CPU on my i7 machine.

Dramatic Acting

As I mentioned when reviewing Krotos Dehumaniser a few years ago, this software is designed for adding sound effects to videos and games using live performances by voice actors. That’s not the only possible purpose, of course, but it seems like an important use case the developers had in mind. So, testing Reformer Pro in this kind of scenario – setting up a microphone, feeding various noises into it, and moving the X-Y pad around – it is very quick and easy to get monstrous roars, electronic buzzes, noisy textures etc, depending on the libraries being used. It seems to take only about a minute to get used to the way a particular library responds and figure out what to feed into the mic in order to get predictable, controllable output which would fit a particular scene.

It takes a little more concentration to make sounds into the mic while controlling the blend on a touchscreen, but this is also easy in practice. Yelling loudly into a mic and then dropping down the volume while moving from, say, the Bengal tiger to fruit and vegetable crunch sounds like a monster that’s roaring, then eating a victim. There’s also a playback speed control for each library, which allows for even lower and unnaturally monstrous roars. Blending a slowed-down leopard with a sped-up tiger and shifting between the two makes for even more drama, and can also be used as a de facto pitch control. Reformer Pro does not seem to use the pitch data of the input, so you don’t need to make a very low growl into the mic in order to get a low growl. However, this does make it harder to create controlled rising or falling growls when needed – that’s where blending between a sped-up library and a slowed-down one becomes a useful tool.

Getting Musical

Since the pitch of the input is not used directly – so singing or playing an A note will not get you a sound tuned to A – using Reformer Pro for music does get more complicated. It is much easier than it is with Dehumaniser, though, as Dehumaniser is standalone software while Reformer Pro (and Dehumaniser II) are plugins which can just be put in your project in a DAW. Let’s start with something easy, however, and use some unpitched musical sounds as an input. I mean, of course, drums. This is a great tool for turning drums into strange glitchy sounds. The input sound does not need to be great or realistic, but it does make a big difference if it’s dynamically varied. In other words, it doesn’t really matter if a hi-hat being used for input has a lot of round robins or velocity layers, as long as its volume responds to velocity – and it’s also good to be able to control its openness to get longer sounds.

Moving the X-Y pad while feeding Reformer Pro drums creates evolving blends of glitches, which is great for taking one drum loop and slowly morphing it from one kind of glitch to another. To take this to the next level, split the drums into separate mixer channels, so that the snare is on a separate channel, hi-hat on another etc., and have a differently configured instance of Reformer Pro in each. The wet/dry control also becomes very useful here, as it can be used to gradually shift the drums from normal to strange, or back again.

Of course, including some dry signal means we no longer lose the pitch information. So, what happens if we run a piano through Reformer Pro with some dry signal? Well, it sounds like gremlins living inside a piano – we get the notes, but each note also “disturbs the monsters’ sleep” and they make groaning, creaking and buzzing noises (depending on what libraries are being used). The monsters very palpably respond to the piano’s dynamics. This is really cool, even if it’s not a sound many of us will need very often.

Things get even more interesting when other effects are applied after Reformer Pro. Envelope-following filters or distortions (such as BPB favorite Tritik Krush) which also use dynamic information to process the sound are great for turning sounds into swishes or just adding grit to the loudest parts. My favorite effect to put after Reformer Pro, though, has to be a vocoder. That lets us put pitch information back into the output, and makes for some of the strangest, most unique synth sounds I’ve ever heard, even when leaving the X-Y pad in a static position. They generally have a very sci-fi vibe, though horror is also achievable. Subtle, gently evolving pads are harder to get but possible, and I get the feeling that I’ve only scratched the surface. Somebody who’s got more experience using vocoders could probably achieve a much bigger variety of sounds.

Creating Monsters

There are currently several libraries available for Reformer Pro – when purchasing monthly licenses, the Black Leopard Pro library is included, while an annual subscription grants access to all current libraries created by Krotos. The libraries contain unlocked WAV files, so they can also be used “the regular way” in a sampler or as audio clips.

It’s also possible to create user libraries and roll your own monsters with the included Analysis tool. This is very simple to use – just point it at a folder which contains WAV files, let it analyze them, and you have a usable library. The real work is making sure the files in the folder are something that will give good results – properly trimmed, with good volume levels, and varied in terms of dynamics and content. My attempt to just throw a few dozen samples of a cracked crash cymbal worked fine, but the results were pretty monotonous. Put in some quiet rides, louder crashes and very loud snares in a folder, though, and the output gets more interesting – it doesn’t really sound like drums because it does not have the drums’ sharp attack, especially when the input has slower attacks, but it has the drums’ timbre. It would probably take me an hour or two to make a useful drum-based library of about 30-50 files.

Very short recordings can’t be used by the Analysis tool, and putting pitched notes in there is probably not a good idea, but other than that it seems you can throw anything in there – ambiances, foley sounds, synthesized textures, and assorted weirdness. This software was only released recently, and given the ease of creating user libraries, this plugin could get even more interesting very quickly.


Reformer Pro is a very interesting plugin which opens up all sorts of sound design possibilities. If you want to use it for sound effects, it’s very quick, easy and practical. If you want to use it for music, then the weirder your music is, the more likely it is that this could become a key tool in your arsenal. So, are you weird enough to get the best out of Reformer Pro? If you want to find out, there’s a 10-day free trial.

More info: Reformer Pro  ($238)

Krotos Reformer Pro Review


Reformer Pro is a very interesting plugin which opens up all sorts of sound design possibilities. The question is, are you weird enough to get the best out of Reformer Pro?

  • Features
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  • Performance
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About Author

D Smolken is a musician, artist and a sampling expert. He creates freely downloadable SFZ libraries available on his website Karoryfer Samples.

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