make-noise-maths

Make Noise Maths

Analog computer: envelopes, LFOs, logic, and more

20 HP Eurorack module

MATHS is an analog computer for musical purposes, combining function generators, attenuverters, a sum/OR bus, and logic outputs into a single expressive module. Channels 1 and 4 generate voltage-controlled envelopes, LFOs, and slew functions ranging from 1kHz to 25-minute cycles, while Channels 2 and 3 serve as attenuverting mixers with built-in DC offset references. Its deep patching possibilities make it equally at home as an envelope generator, LFO, oscillator, comparator, clock divider, or analog logic processor.

Features

  • Channels 1 and 4 are full function generators: envelope, LFO, slew, portamento, oscillator
  • Rise and Fall times from 1kHz to 25 minutes
  • Vari-Response: continuously variable curve from Logarithmic through Linear to Hyper-Exponential
  • Channels 2 and 3 are attenuverting mixers with normalized DC offset references (+10V and +5V respectively)
  • Four-channel SUM bus with normalled Variable Outputs
  • Inverted SUM Output for reversed modulation without external inverter
  • Analog OR Output (maximum voltage selector) for half-wave rectification and weighted CV selection
  • End Of Rise (EOR) output on CH1: 0V or 10V event signal at top of rise
  • End Of Cycle (EOC) output on CH4: defaults to +10V at rest, goes low at end of fall
  • Unity Signal Outputs for CH1 and CH4: NOT normalized to SUM/OR bus, tapped directly from circuit core
  • Voltage-controlled Cycle Input on CH1 and CH4 for gate-controlled run/stop
  • Both CV Input: bi-polar exponential control over entire function; positive decreases time, negative increases time

Controls & Jacks (45)

  • Signal Input— Accepts CV or audio for Channel 1 slew processing, or a gate signal for ASR envelope mode. Normalled to nothing; direct-coupled for both aud
  • Trigger Input— Triggers Channel 1's rise/fall function from 0V to 10V and back. Accepts gates or pulses; re-triggers only during the fall portion, enabling
  • Direct Coupled Channel 2 Signal Input— Audio or CV input for Channel 2's attenuverter. Normalled to a +10V DC reference when unpatched, allowing CH2 to serve as a variable offset
  • Direct Coupled Channel 3 Signal Input— Audio or CV input for Channel 3's attenuverter. Normalled to a +5V DC reference when unpatched, providing a finer offset range than Channel
  • Trigger Input 4— Triggers Channel 4's rise/fall function from 0V to 10V and back. Accepts gates or pulses; re-triggers only during the fall portion.
  • Signal Input 4— Accepts CV or audio for Channel 4 slew processing, or a gate signal for ASR envelope mode. Direct-coupled for both audio and CV.
  • Cycle— Indicates whether Channel 1 is self-cycling. Lit when Cycle button is engaged or when a high gate is present at the Cycle CV input.
  • Cycle LED 4— Indicates whether Channel 4 is self-cycling. Lit when Cycle button is engaged or when a high gate is present at CH4's Cycle CV input.
  • Cycle 1— Toggles Channel 1 self-oscillation on or off. When cycling, Rise and Fall set the LFO speed from sub-audio rates up to 1kHz.
  • Rise 1— Sets Channel 1's rise time from nearly instant (fully CCW) to several minutes (fully CW). Controls attack time in envelope mode, upward slew
  • Attenuverter 2— Scales and inverts Channel 2's signal or, with nothing patched, sets a +/-10V DC offset sent to the SUM/OR buses. Noon is zero output.
  • Rise 2— Toggles Channel 4 self-oscillation on or off. When cycling, Fall primarily controls frequency and Rise adjusts pulse width of the EOC output
  • Rise CV Input— Linear CV input for Channel 1 Rise time. Positive voltage increases rise time; negative decreases it relative to the knob setting. Range +/-
  • Fall 1— Sets Channel 1's fall time from nearly instant (fully CCW) to several minutes (fully CW). Controls decay/release in envelope mode, downward
  • Fall 2— Sets Channel 4's fall time. Controls decay/release in envelope mode and is the primary frequency control when using EOC as a clock output.
  • Rise CV 4— Linear CV input for Channel 4 Rise time. Positive voltage increases rise time; negative decreases it. Range +/-8V.
  • Both CV Input— Bipolar exponential CV that controls Channel 1's entire function duration. Positive voltage shortens the cycle; negative lengthens it. Range
  • Attenuverter 3— Scales and inverts Channel 3's signal or, with nothing patched, sets a +/-5V DC offset sent to the SUM/OR buses. Provides finer offset contr
  • Both CV 4— Bipolar exponential CV that controls Channel 4's entire function duration. Positive voltage shortens the cycle; negative lengthens it. Range
  • Fall CV Input— Linear CV input for Channel 1 Fall time. Positive voltage increases fall time; negative decreases it relative to the knob setting. Range +/-
  • Vari-Response 1— Shapes Channel 1's rise and fall curves from logarithmic (CCW) through linear (center tick) to hyper-exponential (fully CW). Also affects ov
  • Attenuverter 4— Scales, attenuates, and inverts the Channel 4 signal before it reaches the Variable Output and the SUM/OR buses. Noon is zero output; CW is
  • Vari-Response 4— Shapes Channel 4's rise and fall curves from logarithmic (CCW) through linear (center tick) to hyper-exponential (fully CW). Also affects ov
  • Fall CV 4— Linear CV input for Channel 4 Fall time. Positive voltage increases fall time; negative decreases it. Range +/-8V.
  • Cycle Input— Gate input that forces Channel 1 cycling on when high (+2.5V or above) and off when low. Overrides the Cycle button state.
  • Cycle CV 4— Gate input that forces Channel 4 cycling on when high (+2.5V or above) and off when low. Overrides the Cycle button state.
  • EOR— Lights when Channel 1's End of Rise output is high, indicating the rise phase has completed. Off at rest and during the rise phase.
  • Unity— Bi-color LED showing Channel 1's core signal level. Green indicates positive voltage; red indicates negative. Visible even at small voltages
  • Variable Output 1— Channel 1 signal scaled by its attenuverter. Normalled to the SUM and OR buses; patching a cable here removes CH1 from those buses. Range +/
  • SUM— Outputs the analog sum of all four channels' Variable Outputs as weighted by their attenuverters. Use for mixing multiple modulations into o
  • Output 3— Channel 3 signal scaled by its attenuverter. Normalled to the SUM and OR buses; patching a cable here removes CH3 from those buses.
  • Variable Output 4— Channel 4 signal scaled by its attenuverter. Normalled to the SUM and OR buses; patching a cable here removes CH4 from those buses. Range +/
  • Variable Output 4 LED— Bi-color LED showing the signal level at Channel 4's Variable Output. Green for positive, red for negative voltage.
  • EOC— Lights when Channel 4's End of Cycle output is high. Notably, this LED is lit at rest because EOC defaults to +10V when CH4 is idle.
  • End Of Rise Output (EOR)— Outputs a 0V or +10V signal that goes high when Channel 1's rise phase ends. Defaults low when idle. Useful as a clock, delayed trigger, or
  • Unity Signal Output— Taps Channel 1's core signal directly, bypassing the attenuverter. Not affected by the attenuverter setting and does not break SUM/OR bus no
  • SUM Bus— LED indication for Sum Bus signal activity
  • OR Bus Output— Analog OR (maximum voltage selector) of all four Variable Outputs. Always outputs the highest positive voltage present; negative voltages ar
  • SUM Bus Output— Outputs the analog sum of all four channels' Variable Outputs as weighted by their attenuverters. Range +/-10V.
  • Inverted SUM Output— Inverted version of Sum output for greater modulation possibilities
  • OR Bus— Indicates signal level at the OR bus output. Brightness tracks the highest voltage present across all four channels' Variable Outputs.
  • Unity Signal Output 4— Taps Channel 4's core signal directly, bypassing the attenuverter. Does not break SUM/OR bus normalling when patched. Range 0-8V when cyclin
  • End Of Cycle Output (EOC)— Outputs a 0V or +10V signal that goes high at the end of Channel 4's fall phase. Defaults high (+10V) when idle. Patch to CH1 Trigger for ca
  • Cycle 2— Toggles Channel 4 self-cycling (LFO mode). When engaged, CH4 continuously loops its rise/fall function.
  • Attenuverter 1

How-To Guides

  • Voltage Controlled Triangle LFO
  • Voltage Controlled Ramp/Saw LFO
  • Attack-Decay Envelope Generator
  • Attack-Sustain-Release Envelope Generator
  • ADSR-Type Envelope (Complex)
  • Voltage Controlled Clock / Pulse LFO
  • Voltage Controlled Pulse Delay
  • Portamento / Pitch Glide
  • 281 Mode: 90-Degree Phase-Shifted Dual LFO
  • Bouncing Ball (Decelerating Rhythm)
  • Voltage Comparator / Gate Extractor
  • Voltage Controlled Clock Divider

Explore the interactive Maths panel on BleepDex — tap any control to learn what it does.

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