Electro Harmonix - Mainframe Bit Crusher

The Mainframe offers sample rate reduction from 48 kHz to 110 Hz.

A quick reminder...
The sampling frequency is the number of times per second that a sample of an analogue signal is recorded.
For example, CDs (remember those?) had a sampling frequency of 44.1 kHz, which means that the original analogue signal is sampled 44,100 times per second.
The sampling frequency defines the range of frequencies that can be reproduced while maintaining good fidelity.

When the sampling frequency is reduced, the quality of the audio is degraded and aliasing occurs.
Raliasing means audible artefacts created when higher frequencies are sampled at an inadequate frequency and the result is distortion.

The Mainframe's sampling frequency range is wide enough to go from fairly pure sounds to sounds that are unrecognisable from the input signal.

It also provides bit crushing from 24 bits down to 1 bit.
What does this mean?
Bit crushing is a reduction in bit depth.
Let's go back to our CD example...
CDs used a bit depth of 16 bits, meaning that each of its samples was represented by 16 bits of information.
Higher bit depths can accurately represent a greater dynamic range whereas bit overwriting increases the number of sampling errors and creatively degrades the sound back to those nasty old school sounds we love.

The Mainframe's selectable High / Low / Bandpass filter allows the user to shape the artefacts of bit crush and sample rate.
Another very interesting feature is its sample rate adjustment mode where the pedal analyses your input signal in real time and adjusts the sample rate to match the pitch of your signal, or a defined interval above your signal.
This allows you to set the sample rate to match the pitch of a song, or it will continuously adjust the sample rate according to what you're playing!