D16 Group Decimort €35 (PC/ MAC)

As a "high-quality" lo-fi effect we hope the latest SilverLine processor doesn't crush our dreams and leave us in bits

The latest addition to D16 Group's SilverLine range of affordable plug-ins aims to provide a high-quality alternative to lo-fi effects such as Cubase's BitCrusher, Logic's Bitcrusher, and Live's Redux. Pedants will scoff that the 'bit crusher' tag often associated with such digital lo-fi effects isn't too accurate, unless you consider crushing to be the same thing as reduction. More notably, it's not just the bit-depth that's tinkered with - the sample rate can be lowered too, a proces known as decimation.

The sample rate determines how many times a second a signal is digitally recorded - ie, sampled. The number of available digital volume levels that are used to describe each sample is dictated by the bit depth. Lowering the bit depth means that fewer values are available to represent the vertical position of each sample, leading to a 'stepped' waveform - the samples are quantised to a vertical grid. At moderate values, this adds a grungy hiss, but at extreme settings, the wave becomes very distorted.

All artifacts welcome
Though on the face of it these phenomena are undesirable, a little lo-fi can give some funky grit to a sound. Old school samplers from the 1980s were only able to sample at lower rates, giving many productions of the day a crunchy quality that today's technology doesn't impart, and many are keen to recreate such sounds.

Unlike the crude algorithms used in, say, Cubase and Live's bitcrushers, Decimort emulates how the circuitry inside analogue-to-digital and digital-to-analogue converters actually works. D16 tell us that, amongst other things, Decimort interpolates the incoming wave to reconstruct a more 'analogue' version, then applies noise to mimic the natural dither caused by circuitry.

The results are a grittier tone, without the harsh (sometimes constant) 'fizzing' artifacts of lesser crushers, albeit at the expense of higher CPU usage. Decimort really does sound like crusty old digital gear, though whether you actually think this is 'better' is a matter of taste.

Controls-wise, at Decimort's heart are the bit-depth and sample-rate reduction knobs, which range from 1-16 bits (or Off), and 0 to 44.1kHz respectively. Decimort can process left and right channels independently or together. There's also an anti-aliasing filter - see boxout.

Each channel also has a more conventional, tweakable multimode resonant filter with low-pass, high-pass, band-pass and band reject controls. These might not be anything out of the ordinary, but they have a quality sound.

Finally, there's a simple Preamp knob for overdriving the incoming sound. This is a useful effect in its own right and assists in further approximating the tones of old-school hardware. Speaking of which, the presets feature several patches based on classic bits of kit, including Akai's MPC60 and E-MU's SP-1200 samplers.

Decimort isn't groundbreaking, but it does give you very high-quality overdrive, lo-fi and filter effects in a single effect.

Contact: contact@d16.pl
Web: www.d16.pl
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No known aliases
To truly represent a signal, the sample rate must be at least twice the highest frequency present - otherwise, frequencies can be misinterpreted, creating (usually) unwanted artifacts. 44,100Hz gives a 'Nyquist frequency' of 22,050Hz; when sampling, frequencies above this are 'reflected' - eg, an inaudible sine wave of 32,O5OHz becomes an audible one at 12,O5OHz. As for playback, consider a sample rate of lOOHz: the signal level changes only 100 times a second, and each jagged 'step' is essentially distortion.

Decimort recreates these artefacts in all their filthy glory. A switch engages a reconstruction filter, smoothing the changes between output values to remove distortion, as any quality sampler would. It's not currently possible to have this filter placed before the decimator, for dirtying up synth sounds, soaring leads, etc, without introducing unmusical aliasing, but D16 say they'll be adding this in an update.
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System requirements
(PC) Windows 2000/XP, VST host

(MAC) Mac OS X 10.4.3, AU/VST host

Test system
(PC) AMD Turion 64 2GHz, 1GB RAM, Windows XP, M-Audio Fast Track Pro

Alternatively
SoundHack +decimate N/A»N/A»£Free This little freebie from SoundHack is an extremely basic bit- and sample-rate reducer

iZotope Vinyl N/A»N/A»£Free
A lo-fi effect with an analogue rather than digital approach: it makes your tracks sound like vinyl recordings

Verdict
FOR
- Very reasonably priced
- More authentic than typical bitcrushers
- Preamp is useful imts own right
- Built-in filters
- Easy to use

AGAINST
- No pre-filter anti-aliasing

Decimorts handy integration of overdrive, lo-fi and filter effects make it good value for money, and the sound is spot on

MARK:9/10
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