Micron Piano is a Max for Live instrument with a microtonal piano sampler and 256-voice polyphony. Formally named Micronized Upright Piano, this device retunes piano samples in an n-EDO system and a variable tuning pitch. The sound samples were recorded from my 1927 Janssen upright piano. Each sample is tuned to either the octave or tritone and pitchshifted downwards filling in the chromatic scale. The event processing stage parses MIDI input into pitch and velocity values limited to the piano scale. The pitch values are sent to my Microtonal MIDI-to-Frequency component and are retuned according to the selected tuning system, tuning frequency, and chromatic mode. The velocity values are sent to a depth function that places the velocity sensitivity on a variable logarithmic scale. This output controls the amplitude as well as a low-pass filter. The signal processing stage applies a compressor and an equalizer with customized parameters for the piano. This is followed by gain-staging for the make-up gain and the width and level parameters.

The pitch value is sent to the Microtonal MIDI-to-Frequency component comprising of an Align function, a Modal function, and a Tonal function. The Align function shifts the input pitch to calibrate the change of the tuning pitch. TUNE selects an integer as a tuning pitch congruent to the chromatic scale: C32Hz–B63Hz. The Modal function selects the chromatic MODE from the selected SYSTEM, then shifts the PITCH accordingly. SYSTEM selects the quantity of tones per register on a binary logarithmic scale: 12–36 tones. MODE selects the quality of tones through the mode of the chromatic scale parsed into the selected SYSTEM. PITCH selects the quantity of tones within the selected SYSTEM to be shifted upwards. The Tonal function converts the input pitch in the selected SYSTEM from a linear scale to a logarithmic scale and sets it to the TUNE integer.

The signal processing phase takes the audio signal outputs from the poly~ patch and sends it to the Compressor, where COMP sets the threshold. The compression amount above the threshold has a maximum depth of 6dB. This compression is actively visible in the Scope feed at the bottom of the device. The ratio is fixed at 3:1 with a fast attack of 2ms and slow release of 250ms. These parameters are all fixed at a customized setting for this piano. The signal then goes into a post-compression Equalizer. The first two filters are a pair of low-shelf and high-shelf filters with a -3dB slope and fixed at 180Hz and 1.6kHz, respectively. The TONE parameter sets the gain depth of both shelf filters, simultaneously. The next filter is a single low-pass filter with a -6dB slope. The HIGH parameter sets the cutoff frequency of that filter. The last filter is a double high-pass filter with a -3dB slope and fixed at 60Hz. The signal finishes with a gain-staging setup. The WIDTH parameter sets the amount of channel width from a full stereo sound to a mixed mono sound. The LEVEL sets the output gain as well as the gain-staging of the TONE filters and WIDTH parameters.