Electro-Harmonix has launched its Mainframe, a pedal that offers old-school digital sounds alongside some new additions to the bitcrusher format.
The pedal can reduce your signal’s sample rate from 48kHz all the way down to 110Hz – and reduce your bit depth down from 24-bit to 1-bit. At lower settings, your guitar signal less resembles a guitar and more resembles a ZX Spectrum that’s having a hard time reading a copy of Horace Goes Skiing. That’s not to say it’s only fully-glitched-out sounds on offer, as it can also achieve smoothly-tracked synth-esque lead lines.
Normally, when audio is processed digitally, it’s chopped up into samples. To get something resembling normal, organic audio, this has to be done incredibly quickly. Even retro formats like CDs use a whopping 44.1kHz, meaning the analogue source is being ‘sampled’ that many times in a second. The detail per sample is referred to as bit depth: for example, CDs use 16-bit bit-depth, meaning each of those tiny slices is represented by 16 bits (1s or 0s) of information.
The Mainframe, and other bit crushers, let you reduce the quality of that processing to introduce the audio artefacts associated with early digital sounds – squarewave-esque bleeps and bloops.
The pedal’s main section of controls sports knobs for volume, blend, bit-depth reduction and sample-rate reduction. A secondary section allows you to control a filter, switchable between a high-pass filter, a low-pass filter and a band-pass filter.
Expression pedal input also lets you ramp between two presets, sweeping multiple controls with your feet. This can be used, for example, to slowly glide down into glitchy chaos, or do stabs back into sonic clarity.
It can also operate in what EHX calls ‘Sample Rate Tuning Mode’, which can either match the sample rate to the key of a song or track your playing and adjust sample rate accordingly. Set to an interval above your signal, this can also introduce a unique, glitchy harmonisation.
Hear the unit in action with EHX’s demo below:
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