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Klevgrand Fosfat

Drum Reinforcement Plug-in By Paul White
Published September 2022

Klevgrand Fosfat

Fosfat makes it easy to reinforce your drums with sculpted noise or sine waves.

Although described as being ‘transient fertiliser’ and intended specifically to help you add weight and/or definition to drums, Klevgrand’s Fosfat isn’t a transient processor in the classic SPL Transient Designer mould. Rather, it is intended to provide a quick, easy and effective way to perform the classic engineering trick whereby a drum signal is used to key a gate — the idea being that as the gate opens it lets a low‑frequency sine wave or noise source through to add some heft at a kick or tom’s fundamental pitch, or provide additional snap or sizzle for snares and hi‑hats. To this end, Fosfat tracks the dynamics of the incoming sound and adds in tonal and filtered‑noise textures. Importantly, the level of the triggered sounds follows the source level, so the correct dynamics for drum hits of different levels are preserved. Fosfat takes the technique a little further, though, since it allows the user to dial in some pitch drop — which could be anything from an 808 bass drop to a classic Simmons effect — to prevent the oscillator’s contribution from sounding too static.

All of the usual plug‑in formats are supported, including AAX, AU and VST (Apple M1 optimised on Macs), plus AUv3 and standalone support for iPads too. To the upper left of the screen, an envelope display shows both the input signal envelope and the action of the envelope follower, with a Floor control to adjust its sensitivity. The user can adjust the trigger frequency and bandwidth for the trigger signal; like a gate’s sidechain filter, you tune this to reduce the risk of false triggers from spill. There’s a Solo control so you can hear only the trigger signal, and this signal is used to trigger both the oscillator and noise sections.

The oscillator has adjustable Attack and Release sliders with controls for Frequency, Pitch Drop, Gain and a Low Cut filter. The last might seem a curious feature, given that on a clean sine wave a filter can change only the level, not the tone, but it can serve as a ‘safety’ feature, to prevent loud low‑frequency sounds making your speaker cones flap as you experiment. For reinforcing and sculpting the high end, Fosfat can trigger filtered noise, and this can be used to enhance snare or hi‑hat sounds. Again there are separate controls for Attack and Release so you can go from a long sizzle to a short click (which can be used to add attack to kicks too), and you can shape the frequency content with filtering. The user can also adjust the stereo width and gain of the added sound.

It allows the user to dial in some pitch drop... to prevent the oscillator’s contribution from sounding too static.

In Use

Fosfat is incredibly quick and easy to set up, but it’s also very effective in adding life and weight to drums that have either been recorded/programmed in a sub‑optimal way or where the character isn’t quite what you need for a given production. As there’s a common Floor control for the oscillator and noise sections, Fosfat produces the most predictable results when it’s used to enhance individual drum sounds. Used in that way, it is incredibly easy to add both punch and definition to kicks and toms, as well as adding some sizzle to hi‑hats, and with a strong pitch drop and long release time it can also add a convincing electronic Syndrum vibe to kicks, toms and snares. But there’s also plenty of potential for creative use on drum loops too. Of course, it’s much harder to target specific drums in this scenario, but you can tune the sidechain filter, and if you need a different sensitivity or trigger frequency range for the oscillator and noise sections, you can use two (or more) instances of Fosfat.

I don’t really have any major criticisms, particularly at this price, though it might have been nice to include the option of a MIDI output alongside the oscillator and noise sources, so that you could trigger synths, samplers and so forth. Overall, then, Fosfat is a very handy tool that’s easy to use and very effective both for creative processing and for rescuing limp drum recordings. Well worth checking out.


A quick, easy and effective means of reinforcing or reviving drum sounds by layering in an oscillator or noise source.


Full price $39.99. Discounted to $23.99 when going to press.

Full price $39.99. Discounted to $23.99 when going to press.