Docs

Main Keys

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ON / sound

Hold ON to power on.
Hold sound + 1-16 key to select the target channel.

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pat

Hold pat + 1-16 key to select an edit pattern. When playing, the pattern won’t change until the end of the bar. Hold and select multiple patterns to setup a playback chain (up to 16 chain steps)

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prm

Hold prm + 1-16 key to select a parameter on the current voice to edit. Some other keys have additional parameters, and some keys have a second page of parameters that can be entered by pressing the key twice while holding prm.

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exit

Hold exit + ON to shut down the device. exit + pat to clear the current pattern. exit + smp + 1-16 to clear a sample.

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smp

Hold smp + 16 to sample

Sequence Keys

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mute:lfx

Hold mute + 1-16 key to mute a sequence channel.

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page

Choose edit page when sequencing patterns with more than 16 steps.

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play

Start playing back the pattern. When in sync input mode, will wait for an external trigger to start.

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rec

Switch between sequence recording and note playing for the 16 keys. Rec + play to enter “live record”.

1-16 Keys

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1-16
  • Live play notes when record is disabled.
  • Enter sequence steps with record enabled.
  • Hold prm + 1-16 to choose parameter

Quick Start: Bleep

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Turn On

Hold ON (top left key) to turn on the device.

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Play

Press a 1-16 key to play a note. As you are doing further edits, keep pressing the 1-16 keys to hear your sound change.

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Edit the Sound

Hold prm + 5 (env1) then turn the B knob to increase the decay on the sound. It will ring out for longer.

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Wobble

Hold prm + 11 (Lfo Target), then choose Cut to route the LFO to cutoff. Hold prm + 7, then edit the Rate and Depth to change the wobble amount.

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Main Osc

Hold prm + 16 (Mode), then choose Synth with the A knob, and WMAP with the B knob. Hold prm + 1 (timbre) then edit the sound with the A + B knobs.

Quick Start: Repeat

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Step Record

Press the rec key (lower right) to enter record mode.
Now Press the 1-16 keys to set the current note to play on those steps.
Press play (above rec key) to hear the pattern playback.

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Live Record

Exit play mode, then hold rec + press play. This will enter live write (play button will light up red).
Press the 1-16 keys to enter notes live.

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Conditional Triggers

Hold prm + 14 (prob) then use A to set Rnd and B to set the percentage of notes that will play randomly.

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Parameter Lock Live Record

Hold prm + 2 (Filter) to enter cutoff editing. Hold down the rec key and twist the A knob to store a live filter cutoff sequence.

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Parameter Lock step

Hold prm + 15 (Fxs). Make sure write is on (rec key is red) but live write is off (play is green or unlit). Hold down a step that has a note recorded (the 1-16 key is purple). While holding this key rotate A knob to increase the delay fx send for this step.

Parameters

Hold prm & press one of the 1-16 buttons to select a parameter. When a parameter is selected, it will be displayed onscreen, and using the a/b knobs will edit it. Most parameters apply to the voice across all patterns, except as noted.
Note:
Some parameters have a second page, which is accessed by holding prm & pressing the 1-16 button a second time while already on this page.

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timbre / color

When in synth mode, this affects the voice. See the Synth information for details on what each knob does. In Sample mode this changes sample in / out points. In midi mode this edits velocity & hold time.

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filter

Lowpass filter, A controls cutoff, B controls resonance.

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vol / pan

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pitch

A controls legato, the speed at which pitches slide to the next pitch. B controls fine tuning of the note.

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Envelope 1

This envelope is always routed to volume, but can be optionally routed to a second target. A controls attack time, B controls decay time.

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Envelope 2

This envelope is unrouted by default. It can be routed to a single target. A controls attack time, B controls decay time.

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LFO

The LFO speed is derived from the current tempo, so changing the tempo will alter this speed. A controls speed, B controls depth.

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retrig

A controls speed. Lower speeds are faster. B controls Length. Length is how many retriggers there will be.

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Env 1 Destination

An additional routing for the Env. Depth is how much the envelope effects the parameter. Negative depth reverses the effect of the envelope (fades out then in).

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Env 2 Destination

A controls routing for the second Envelope. This is required on Env 2. B Controls depth, how much the envelope effects the parameter. Negative depth reverses the effect of the envelope (fades out then in).

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LFO Destination

A Controls destination for the LFO.

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Retrigger decay

A controls if the retrigger fades in (negative) or fades out (positive).

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Pattern Length

How many steps this voice uses on this pattern, and how fast each step is. This can be set per voice per pattern. When editing this parameter, press prm+13 again to double the pattern length, copying the existing pattern twice as long.

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Probability

Sets a random probability for each step (or an individual step is set via parameter locks). A sets condition type, Rnd or Len. B controls the condition depending on the type.

  • Rnd: randomized probabilty of trigger
  • Condition: Len sets a number of time the step plays per pass through the pattern. For example 1:3 will play on the first pass through the pattern, every 3 times through the pattern.

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Effects Sends

Delay and reverb sends. Press prm+fxs a second time to access delay settings. The delay is a simple digital buffer, so live edits will introduce glitches.

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Mode

Under the voice mode parameter (16) - there are three submodes, each with several options. A controls the primary mode, and B controls the secondary mode.

  • Synt: A set of oscilators and drum triggers based on the mutable instruments Braids. More information on the oscilators is available in the braids documentation.
  • Samp: Simple sampler.
  • Midi: Midi output control.

Special Parameters

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prm + play: Bpm, Sync, and Global Volume

Sync can be set to PO (2 pulses per quarter note, pocket operator), 4PQ (4 pulses per quarter note, volca), Midi, or a combination of midi & one of the other two. Press a second time to access Sync Out and global volume settings.
High global volumes can cause distortion on the output, which may be desired.

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prm + rec: Root note & Scale

Octave and root note apply to the 1-16 buttons. Press a second time to access different scales. These settings will not change existing recorded notes.

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prm + pat: Pattern change length

During playback, when you change patterns, audcalc will wait until the end of this bar length before changing patterns. This setting allows you to change patterns slower or faster. Useful if you want to change every four measures.

Sequencing

There are two ways to record notes into a pattern, step mode & live mode.

Step Mode

While write is not lit, choose a note by pressing a button 1-16. Then press rec to enter recording mode. Pressing buttons 1-16 will enter the last selected note on those steps.

Live Mode

While rec is not lit, and the pattern is not playing, hold rec, then press play. Once in live mode, notes played using the buttons 1-16 will be stored in the current pattern.

Parameter Lock

While in step mode, hold down a lit step and move a knob to store a parameter lock for that step. There are 128*16 parameter locks available.
While in playback, holding down record and moving a knob will store parameter locks for playing steps as it passes.

Edit Page

To change the page you are currently editing for the pattern, press the page button. This only applies if the pattern has more than 16 steps.

Edit Controls

Copy Voice

Hold rec + sound + 1-16 to copy the current voice to a different channel. This will overwrite the voice in this channel.

Copy Pattern

Hold rec + pat + 1-16 to copy the current pattern to a different pattern.

Erase Pattern

Hold exit + pat to erase the current pattern.

Erase Voice

Hold Exit + prm to erase the current Voice.

Technical Notes

Voice stealing

There are 8 voices, but 16 sequence channels. Voices are grouped in pairs, 1-5, 2-6, 9-13 and so on. Voices will be muted when a voice from their pair starts playing. This does not apply to midi channels.

Startup in usb boot

Hold rec while plugging in usb (from device off) to enter usb boot mode. This allows you to flash new firmware.
There are also two small buttons on the right of the unit. The top is uboot, and the bottom is reset. Hold uboot (top button), then press reset (bottom button) to reboot in USB mode.

Clock Sync

The clock sync can be driven in PO mode (pulse per 1/8th note) or volca (pulse per 1/16th note). The audio input has protection diodes, and will clamp input voltages.
Note If there is crosstalk with loud clock signals, use the included attenuator to lower the volume of the signal.

Specs

  • Midi in (trs a or b)/ out (trs a)
  • Usb charging and Usb midi
  • Audio in / out (audio click sync on left channel)
  • 32x128 oled screen
  • 2 potentiometers for data input
  • 16 sequencing channels with 8 synthesized voices, or 16 midi out voices
  • 16 patterns with 4096 pattern locks. Patterns support 1-64 steps, with conditional triggers
  • Sampling from audio in or onboard mic

Open source / Thanks

Audcalc would not have been possible without tons of open source software. AudCalc also is open source and is permissively licensed where possible. Full license details are on https://github.com/jonbro/Audcalc/

Auto Crossover Midi input circuit is used with permission from kay / lpzw modules

M6x11 is free to use with attribution by Daniel Linssen

ZLib/libpng licence covers the following portions of the code
Nanopb Copyright (c) 2011 Petteri Aimonen

The MIT License covers the following portions of the code
SSD1306 rp2040 driver Copyright (c) 2021 David Schramm
Braids Copyright 2012 Emilie Gillet (emilie.o.gillet@gmail.com)
TinyUsb
Copyright (c) 2019 Ha Thach (tinyusb.org)
Copyright (c) 2020 Jerzy Kasenbreg

Software License Agreement (BSD License) covers the following portions of the code
gfx_font Copyright (c) 2012 Adafruit Industries. All rights reserved.

BSD 3-Clause "New" or "Revised" License covers the following portions of the code
ws2812 driver Copyright 2020 (c) 2020 Raspberry Pi (Trading) Ltd.

Apache license v2 covers the following portions of the code
q15 math Copyright (C) 2010-2022 ARM Limited or its affiliates. All rights reserved.
Christophe Favergeon

ZLib/libpng licence covers the following portions of the code
Nanopb Copyright (c) 2011 Petteri Aimonen

Thanks to Morgan & Ziv for letting me play with this stuff so much. Its been a journey.

Greetz to the Plinky Discord. What a weird feral synth chat room. Wouldn’t have been possible without you.