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INA GRM Tools 3

Sound Design Plug-ins By Sam Inglis

The long‑awaited version 3 of the GRM Tools suite introduces three new plug‑ins, the likes of which have not been seen or heard before!

With resizeable windows, at last it's possible to make your plug‑in interfaces tesselate... Here, the eight plug‑ins that make up the Classic Bundle are all operating on the same track. It sounded great.With resizeable windows, at last it's possible to make your plug‑in interfaces tesselate... Here, the eight plug‑ins that make up the Classic Bundle are all operating on the same track. It sounded great.

There are a handful of music technology products that become ubiquitous, to the point where it's almost assumed that anyone working in a particular field will have them. It's a rare recording studio these days that could survive without offering its clients access to Pro Tools, for example, or Auto‑Tune. And in the world of sound design, GRM Tools arguably has similar status. Developed by the Group de Recherches Musicales in France, GRM Tools has a long pedigree. It was launched some 16 years ago as a TDM plug‑in suite for Pro Tools, with a native VST version emerging five years later. However, development since then has been relatively quiet, as is attested by the fact that the new version under review here is only the third 'integer' release in its history.

The big news in GRM Tools 3 is the inclusion of three new plug‑ins — Evolution, Grinder and Fusion — but the existing tools have also received a spruce‑up, and their organisation into bundles has also been changed. The three new plug‑ins form the Evolution Bundle, while the 12 older effects are divided into a Classic Bundle and a Spectral Transform bundle. The full GRM Tools Collection includes all 15 plug‑ins. Authorisation is now handled using an iLok key, and support now extends to Audio Units on Mac, with cross‑platform VST and RTAS versions. New to version 3 are stand‑alone versions of all the effects, but there don't seem to be TDM versions of any of the v3 plug‑ins.

Looks Nice

As it has been more than a decade since SOS looked at a version of GRM Tools, I'll offer a quick overview of the older plug‑ins as well as a more detailed look at the Evolution Bundle. All of them share a common look, and one of the best features of GRM Tools has always been the thought and attention given to the user interface. Most of the plug‑ins take advantage of the graphical display to provide a 2D, X‑Y controller that is mapped to the two most important parameters. Each instance of a plug‑in can store up to 14 snapshots of all its settings, and is designed to morph smoothly between them. You can either have the plug‑in morph automatically over a user‑defined (and tempo‑sync'able) time period, or drag a slider, along which eight presets of your choice are marked like inches on a ruler. Hitting snapshot 15, meanwhile, generates a random patch based on the existing snapshot, and snapshot 16 randomises everything!

Talking of sliders, a really nice and unique touch is the 'rubber banding' that allows you to adjust GRM Tools controls slowly yet smoothly, in a way that's usually impossible with a mouse. This is achieved by Ctrl‑clicking on a slider, whereupon a virtual piece of elastic appears to connect it and the mouse pointer: hard to describe, but extremely intuitive and very useful in practice.

New in version 3, and in fact new to the plug‑in world as far as I'm aware, is that the user interfaces are dynamically resizeable: you can simply click in the bottom right‑hand corner and drag to change the dimensions of the plug‑in window (though it's not possible to make the window smaller than its default size). Text labels and buttons remain a fixed size, but sliders and the graphical window with its X‑Y controller are scaled to fit. Tragic individual that I am, I spent fully 10 minutes with mouse in hand gawping at the novelty of it all!

Another interesting new interface feature is what the makers call Agitation. This basically introduces something a bit like a random LFO for every parameter, which can be switched on by clicking the magenta blob next to that parameter's numerical value readout. Two global controls set the amount and the time period of this Agitation. It's a simple idea but very effective, allowing you to unleash anything from a small amount of organic variation through to bizarre, tempo‑sync'ed mayhem.

Classiques Nouveau

Many of the eight effects in the Classic Bundle were ground‑breaking when first introduced, but some have been widely imitated. Most of what's possible with Band Pass, for instance, can be done in the EQ bundled with a typical DAW host. Functionally, it's a fairly basic single‑band filter that can be set to band‑pass or band‑reject modes, although easily recreating the way you can morph between snapshots here would be a challenge in conventional EQs.

Likewise, there have been plenty of other comb‑filtering and resonator effects, but the morphing features and the simple user interface make it very quick to get results from the GRM Tools Comb Filters and Reson plug‑ins. The former offers five comb-filter bands, each having its own frequency, resonance and low‑pass settings, plus master controls that adjust the same settings for all five bands simultaneously. In essence, it turns anything you feed into it into a pitched (though sometimes very dissonant — it's a shame the frequencies can't be set using musical intervals rather than values in Hertz) sound, and the range of possibilities is surprisingly large. In small doses, it can add a nice musical 'bounce' to a drum track, while turning the resonance up and the frequencies down can yield awesome, driver‑frying rumbles and booms. Reson, meanwhile, gives you up to 128 filter bands, each of which resonates at its own specific frequency, plus a number of global controls governing how these are spread out across the frequency spectrum, how much resonance is applied, and so on. With fairly broad settings, the effect is a little like playing something into an out‑of‑tune piano with the sustain pedal held down, so that you can hear the open strings resonate sympathetically.

Freeze and Shuffling are arguably the grandparents of all today's 'granular' effects, and although they're quite simple compared with newer plug‑ins from other manufacturers, they're nonetheless both fun and effective. Freeze is based around a 30‑second buffer that samples the audio input. You can then specify the start and end points of a 'window' within this buffer, which is looped, layered and pitch‑shifted in a variety of ways while the 'window' is dragged around in real time. Possible effects range from thick phasing to out‑of‑control, arrhythmic mayhem. On my system, I found it frustratingly hard to move the start and end points of the 'window' reliably, and I also wished that more of Freeze's parameters could be tempo‑sync'ed — for rhythmic purposes, it would be brilliant if you could set the length of the sampling 'window' to be a fixed number of beats.

Shuffling also employs an input buffer, this time only three seconds in length, from which fragments are sampled in a semi‑random fashion according to various parameters. You can set the length of the fragments, and decide how abruptly they should transition; you can also set start and end pitch‑shift values, so that each fragment can be pitched up or down, or made to 'swoop' from low to high or vice versa. Compared with some of the granular processors that have emerged in recent years, it's pretty basic, but once again what it lacks in sophistication it more than makes up for in ease of use. The handful of parameters on offer here are plenty to create a wide range of effects, from evil, grinding, crunching distortion to hyperactive random drum loops. Once again, though, it's a shame that none of the sound‑mangling parameters can be sync'ed to host tempo.

Delays has much in common with the early-reflections algorithms in typical algorithmic reverb plug‑ins. It makes available up to 256 delay lines, with global control over their distribution in time and amplitude. With no filtering, the potential for naturalistic effects is fairly limited, but some monstrous noises can be obtained, especially when you use parameter morphing.

Doppler is, at root, a panner, but one that attempts to mimic the audible effects of motion and distance. You use the mouse to drag the sound source around a 2D 'map' with the listening position in the centre. Movement towards or away from the centre causes a fairly convincing Doppler pitch change, and as you get further away, the amplitude and frequency content of the sound are attenuated in a reasonably lifelike fashion. It's nowhere near as sophisticated as the brilliant Spat plug‑in from Flux's IRCAM Tools, but nor does it require an entire CPU core of its own to run!

My favourite of the Classic Bundle effects is definitely Pitch Accum, which is a simple idea that works surprisingly well. In essence, what happens is that the input signal is fed first into a modulating pitch‑shifter, which in turn feeds a delay line. The range of sounds this can create is quite remarkable, from really meaty phasing, flanging and doubling effects through to settings that will turn cymbals into orchestral stabs, not forgetting preset number five, which regardless of what you feed into it, seems to generate the classic 'waking up from a dream' noise beloved of cheap films through the ages.


The Spectral Transform bundle takes in the fairly conventional Equaliser alongside the distinctly unusual Contrast, FreqWarp and FreqShift plug‑ins.The Spectral Transform bundle takes in the fairly conventional Equaliser alongside the distinctly unusual Contrast, FreqWarp and FreqShift plug‑ins.

And so to the Spectral Transform bundle and the intriguing Contrast plug‑in. This is an interesting multi‑band dynamics tool that, like so many of the other GRM Tools, offers in immediacy what it lacks in in‑depth editability. Here, the 2D window displays a Fourier analysis of the input sound, which is divided into three sections using horizontal lines. These define thresholds at which the sound is considered to be 'strong', 'weak' or 'medium'. The input sound is further divided into up to 256 frequency bands per channel, so that each band is 'graded' dynamically as being either strong, medium or weak. Simple sliders then adjust the relative levels of each category in the reconstructed signal, and a Smoothness parameter changes how quickly Contrast responds to changes in the timbre of the input signal.

It's an interesting and quite unusual effect, although personally I can't imagine following the manual's recommendation and using it in a mastering context! Bringing up the level of the 'weak' frequency components, in particular, can radically change the source sound in unpredictable ways. However, this was one plug‑in where I found the limited parameter set rather restrictive. For instance, with many real‑world sources, the 'strong' elements of the signal pretty much equate to the low frequencies; it would be great if there was some flexibility to tailor the 'angle' of the thresholds across the frequency spectrum to compensate for this.

Of all the GRM Tools, the Equalise plug‑in is perhaps the one that shows its age most of all. It is, really, nothing more than a 31‑band graphic equaliser, though once again the preset morphing capabilities make it capable of moving effects that would be hard to achieve with standard DAW plug‑ins.

FreqShift is a combined frequency shifter and scaler, which first divides the incoming signal into up to 4096 frequency bands, then adjusts their distribution within the frequency spectrum. The Shift parameter simply moves every band up or down the spectrum by a fixed value of your choice, the result of which is usually to make pitched sounds enharmonic, while the Scale parameter does a similar thing, but using multiplication rather than addition. Scaled signals thus usually retain their pitched, harmonic quality, though the process isn't really useful for transparent pitch‑shifting! This is another one of those effects that has arguably been superseded by more modern takes on the same idea, though it does have the advantage of being child's play to use.

Finally, FreqWarp is perhaps the most off‑the‑wall effect in this bundle. Conceptually, it's very simple: once again, the input signal is divided into up to 4096 bands. The frequency content of each band is then remapped according to a line you draw on a two‑dimensional graph. As a simple example, you could just draw a straight line from the top left to the bottom right corner to 'reverse' the frequency content of the signal, so that low frequencies become high frequencies and vice versa. It's capable both of extreme effects and subtle spectral rebalancing, although the latter is never exactly transparent, and once again, features such as preset morphing and Agitation contribute to an ease of use that compensates for a simple feature set.


The Evolution Bundle plug‑ins in action. Here, the drum loop that is being fed through the Fusion plug‑in (opposite page) meets its doom at the hands of Evolution, before being modulated with a solo vocal in Grinder. The Evolution Bundle plug‑ins in action. Here, the drum loop that is being fed through the Fusion plug‑in (opposite page) meets its doom at the hands of Evolution, before being modulated with a solo vocal in Grinder.

For existing users, the most interesting part of the new version 3 GRM Tools will naturally be the new bundle of three plug‑ins called Evolution. All three are considerably more complex than the existing tools, and promise genuinely new effects.

The eponymous Evolution could be thought of as a spectral sample & hold effect. It takes snapshots of the frequency content of its input, then morphs between these, in essence creating a continuous sound that has (initially, at least) the timbre of the original but almost none of its dynamic variation. This timbre can be completely 'frozen', so that it morphs to a new snapshot only when you hit the 'sample' button, or it can be made to update periodically or randomly. The character of the frozen sound itself can be manipulated in various ingenious ways. A 'purity' slider allows you to progressively eliminate low‑level frequency bands so that you're left with only the strongest frequency components, and there's also a parameter called 'grain' which "adds random variations to the frequencies and amplitudes of each component”. Finally, Evolution features the same Scale and Shift parameters as FreqShift, allowing the timbre to be dragged around the frequency spectrum.

In practice, Evolution is both rather wonderful and unlike any other effect I've tried. Feed a drum loop into it, for example, and you can generate ethereal, icy clouds of noise that are like waves crashing on beaches in the land of dreams. Apply it to voices and instruments and you're in the twilight world where weird, treated reverbs morph into synth pads and textures. What's impressive is that most of these fall out without a great deal of effort. Under the hood, Evolution is obviously a lot more complex than the earlier GRM Tools, but most of that complexity has been hidden from the user, and it's an absolute joy to work with.

Fusion is, likewise, a genuinely original yet brilliantly simple idea. It is, at heart, a multi‑tap delay, but with a very novel twist. You use the mouse to position up to eight 'tape heads' across a scrolling display, and the twist is that the audio that scrolls across the display is plotted by frequency: high frequencies scroll across the top and low frequencies across the bottom. The 'tape heads' can be any height you like, so that you can effectively filter out high or low frequencies by making the tape head shorter. More interestingly, they can also be positioned at any angle, so high frequencies are tapped before low frequencies or vice versa. Each 'head' has its own feedback and pan controls, and if you use its slider rather than the 2D graph to set delay time, can be sync'ed to host tempo.

Even when you only use vertical 'tape heads', the sound can get pretty wild, and as soon as you start to angle them, the original signal rapidly becomes unrecognisable, buried under swoops and swirls. Add in the motion that preset morphing and Agitation bring to the party, and what you have is a pretty powerful sound-design tool, albeit one that has a definite and very recognisable character — it's perhaps not as versatile as the other two plug‑ins in the collection. For some reason, there don't seem to be any factory presets, so you'll need to create your own if you want to see how the morphing works. Doing so is well worth while.

The unique Fusion plug‑in feeding on a drum loop. The vertical bars represent drum hits, and the white lines are Fusion's 'tape heads'. The unique Fusion plug‑in feeding on a drum loop. The vertical bars represent drum hits, and the white lines are Fusion's 'tape heads'. Finally, Grinder is a very interesting new take on the principles of a vocoder. The input sound is 'decomposed' into a large number of separate sine‑wave components, then reconstructed again. You can choose to leave the frequency content and dynamic variation of each band untouched; theoretically, in that case, the sound should be degraded according to the number of frequency bands used, though in practice this seems simply to bypass the process. You can also choose to progressively 'freeze' the changes in frequency or amplitude by dragging a cross‑hair around the main 2D graph. The audible results of doing so are, again, heavily dependent on the number of bands into which your signal has originally been divided. Freezing the frequency variation while leaving the dynamics intact results in a 'cheap digital' distorted ringing sound at low Bands settings, whereas at the maximum 4096 bands, the effect is of a weird and often rather sinister smearing, almost like a short backwards reverb. Freezing the dynamics produces a whole other world of cheap digital noises with few bands, while ramping up the Bands settings yields some truly creepy 'frozen' effects.

There's plenty to like here, but the real fun comes courtesy of the plug‑in's ability to load in another sound file to use as a modulator. You can then use a Balance control to move between extremes where the output takes all of its frequency information from the source input and its dynamics from the auxiliary sound file, and vice versa. I got some truly lovely results by modulating a drum loop and a solo vocal, especially with the number of bands set to the maximum 4096. Again, the effect often has some of the qualities of a weird reverb or delay about it, but not one I've ever generated using any other plug‑in. The 2D controller works really well here, allowing you to leave things fairly subtle for the most part, then simply drag it to a new spot when you want a particular word or note to leave a trail of weird, frozen delays. It's a slight shame that Grinder can't accept a real‑time side‑chain input instead of loading an off‑line file, though.

All In All

Despite their impressive pedigree, I have to confess that I had never used the original GRM Tools plug‑ins to any great extent before writing this review. Now that I have done, I can see exactly why they have become so ubiquitous in sound design. Unlike lots of unusual and innovative effects, they are very easy to get to grips with, and the user interface is a joyful experience, though I should mention that the GRM Tools plug‑ins seemed to cause occasional freezes in Cubase 6 on my computer, usually when I attempted to dismiss a plug‑in window.

It's probably fair to point out that although they will be invaluable in sound design, their usefulness in music production is likely to be more patchy. On the one hand, I'm pretty sure you could generate entire albums of ambient electronica using just a drum loop and a chain of GRM Tools plug‑ins, and that those albums would be involving, varied and potentially beautiful; on the other, there would be limited scope for using these effects in a rock mix, and thanks to the rather half‑hearted implementation of tempo sync, they're not as dance‑friendly as they might be. Many of the older plug‑ins in the Classic and Spectral Transform bundles are quite unsophisticated compared with more recent takes on the same concepts, and it's not hard to find freeware plug‑ins that can perform many of the same roles, albeit perhaps without the same hands‑on immediacy. However, it should be remembered that the Classic and Spectral Transform bundles have a lot of dedicated fans who, perhaps, like these plug‑ins just the way they are, and will be very pleased that INA haven't fixed anything that wasn't broken in creating these latest versions.

What is, I think, unarguable is that the three new plug‑ins in the Evolution bundle are both genuinely innovative and highly usable. They, too, are unlikely to find a place on a Foo Fighters album, but if your tastes run to the ethereal, spooky, uncanny or downright weird, I'd highly recommend you try them out.    


  • The three effects in the new Evolution Bundle sound like nothing else, and will add a new dimension to any sound‑design toolbox.
  • All of the plug‑ins are child's play to use, even where the underlying processes are quite complex.
  • Existing users will welcome the updates, which bring worthwhile improvements without diluting the special appeal of these plug‑ins.
  • They have resizeable windows!


  • Many of the older plug‑ins now look a little basic in comparison with modern takes on the same ideas.
  • Some key parameters still can't be sync'ed to host tempo.
  • Not completely stable on review PC.


Fans of GRM Tools have had to wait a long time for this, but the new Evolution Bundle rewards their patience in spades.


Complete Collection €550; Evolution Bundle €310; Classic and Spectral Transform bundles €240 each. (in French!)

Complete Collection $800; Evolution Bundle $450; Classic and Spectral Transform bundles $350 each. (in French!)

Published September 2011