Ina-GRM GRM Tools ST

GRM Tools ST (Spectral Transform) adds four exceptional processors — Contrast, Equalize, Freq Warp and Shift — to a plug-in family already packed with winners. 10/01/2003 8:00 AM Eastern

GRM Tools ST (Spectral Transform) adds four exceptional processors— Contrast, Equalize, Freq Warp and Shift — to a plug-infamily already packed with winners. Although these FFT-based plug-insare at their most powerful when used subtly, they practically dare youto attempt the outrageous.


One of my favorite features of the GRM Tools plug-ins is the abilityto interpolate between presets. You can do this manually with theSuperSlider or automatically by clicking a Preset tile. Once you have afew choice presets, you can set the rate of change between them frominstantaneous to 30 seconds. But you can also exercise real-timecontrol over the changes for improvisatory adventures in processing.For this kind of work, I often use Shift, an exceptionally powerfulfrequency-shifter plug-in, which features a controller called theElastic String.

When you hold down the Command key while moving the mouse away fromShift's Scale/Shift icon, the Elastic String appears between the cursorand the icon. Immediately, the icon will begin traveling toward thecursor's position. The longer the Elastic String, the slower the iconwill move. This effect allows you to try out different processingtrajectories through space in real time. If you like what you find andwant to automate it, then you can save each point as a preset and morphbetween them.

You can also keep the Elastic String to a minimum and quickly towthe icon around the frequency field on a short leash. When you find aresonant place or sweet spot, the short leash allows you to easilycircle around it. Remember to keep your CD recorder going when you workthis way, just in case you find something special.

If gradual changes aren't working for you, then you can make theScale/Shift icon jump immediately to any position in the frequencyfield by clicking anywhere in the field and moving the cursor slightly.This is a great trick when you have a loop going and you want toradically change its sound to the beat.


The Contrast plug-in is a compressor/expander that analyzes youraudio input's frequency spectrum. The plug-in's GUI lets you manuallydetermine the comparative amplitude levels of the strong-est (theslider marked S), average (the slider mark-ed M for medium), andweakest (the W slider) parts of the spectrum. You can hone in on thefrequency area that you want to modify by moving the verticaldelimiters around the target spot: Low frequencies are to the left, andhigh frequencies are to the right (see above). The position of anddistance between the horizontal delimiters determine the relativestrength of each part of the frequency spectrum.

Contrast is a great plug-in for mastering-type jobs because you canuse it to locate and enhance the weaker parts of the spectrum and bringout lost detail. You can also use it to soften and smooth out edgy andover-the-top aspects of an audio file.


Contrast is also a wonderful tool for finding and exploitingresonant elements in a rhythm track or loop. Begin by narrowing thevertical and horizontal delimiters to their extreme positions, as wellas maxing out the level of either the weak- or medium-amplitudecontrols. Next, hold down Shift, click within the vertical band andslowly move your mouse while listening for resonant peaks orinteresting rhythmic artifacts. If you find something you like, thensave the position of the delimiter bands as a preset by holding downthe Command key and clicking on one of the numbered Preset tiles.Repeat this several times until you've built up a bank of presets.Don't forget to move the position and width of the horizontal bands asyou work, because their placement is just as important while you arelooking for interesting sounds.

Once you have a handful of presets to work with, set the timingslider to a low value so that your presets change quickly, but notquite instantaneously. Now, toggle through your presets in time to theloop so that different aspects of it pop out to the beat. Graduallyincrease the interpolation time to greater values until the rate ofchange locks in with the music over large phrase lengths.


A couple of interesting features added to the native Mac OS Xversion of GRM Tools ST are the randomizing presets. Preset 15, forexample, changes your current settings by 10% in a randomized fashion.This is useful if you're looking for inspiration, but only in smalldoses. On the other hand, if you're looking for a radical change,preset 16 will randomize your settings completely.

Laura Pallanck wishes to thank Ben Chadabe for assistance withthis article.

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