Modular Synth Terminology Reference
🎚️ Control and Modulation Terms
| Label | Meaning | Description |
|---|---|---|
| CV | Control Voltage | Analog voltage (often 0–5V or -5V to +5V) controlling parameters such as pitch or cutoff. |
| LFO | Low-Frequency Oscillator | Generates a slow cyclic waveform (below ~20 Hz) used for modulation. |
| ENV / EG | Envelope / Envelope Generator | Produces a voltage contour (ADSR, AR, etc.) in response to a gate or trigger. |
| ADSR | Attack, Decay, Sustain, Release | Classic 4-stage envelope shape used for amplitude or filter. |
| AR / ASR | Attack-Release / Attack-Sustain-Release | Simpler envelope forms. |
| PWM | Pulse Width Modulation | Modulates a square wave’s width for richer timbres. |
| FM | Frequency Modulation | One signal modulates another’s frequency. |
| AM | Amplitude Modulation | One signal modulates another’s amplitude. |
| RM | Ring Modulation | Multiplies two signals, producing sum/difference frequencies. |
| S&H | Sample and Hold | Captures and holds voltage values, creating stepped/random signals. |
| VCA | Voltage Controlled Amplifier | Controls amplitude via CV. |
| VCF | Voltage Controlled Filter | Controls filter cutoff via CV. |
| VCO | Voltage Controlled Oscillator | Oscillator whose pitch is controlled by voltage. |
| VC | Voltage Controlled | Prefix meaning voltage-controllable (VC Delay, VC Mixer, etc.). |
| MOD | Modulation | A control signal (usually CV) affecting a parameter (e.g. filter cutoff, pitch, PWM). |
| MOD POLARITY | Modulation Polarity | Determines whether modulation adds to (positive), subtracts from (negative), or affects both directions (bipolar) around the base value. |
| KB | Keyboard Control Voltage | CV output from a keyboard, usually 1V/oct, used to track pitch across modules. |
🎛️ Signal & Audio Path Labels
| Label | Meaning | Description |
|---|---|---|
| IN / OUT | Input / Output | Where audio or CV enters/leaves a module. |
| AUDIO | Audio Signal Path | Indicates this connection carries audio. |
| CV IN | Control Voltage Input | Modulation input controlling a parameter. |
| GATE | Binary On/Off Signal | Triggers or sustains an envelope or note. |
| TRIG / TRIGGER | Trigger Pulse | Very short signal to start an event. |
| CLOCK / CLK | Clock Signal | Periodic pulse used for synchronization. |
| RESET | Reset Input | Restarts an LFO, sequence, or envelope. |
| SYNC | Synchronize | Aligns phase between oscillators or modulators. |
| ATT / ATTEN | Attenuator | Reduces CV or audio level. |
| OFFSET | Adds Constant DC Voltage | Shifts the baseline voltage. |
| MIX / MIXER | Combines Signals | Blends multiple sources. |
| INV | Invert | Flips the signal polarity. |
| SUM | Summing Output | Combines multiple voltages. |
| MULT | Multiple | Passive or buffered splitter that duplicates one signal to several outputs. Each numbered group (e.g. MULT 1, MULT 2) is independent. Unlike stacked cables, multiples provide cleaner, more reliable duplication—especially important for accurate pitch or modulation signals. |
| HOLD | Hold | Maintains the current voltage while active (used in S&H, EG sustain, or track/hold circuits). |
🔉 Oscillator & Waveform Labels
| Label | Meaning | Description |
|---|---|---|
| SIN / SINE | Sine Wave | Smooth waveform, pure tone. |
| TRI / TRIANGLE | Triangle Wave | Linear rise/fall; gentle harmonics. |
| SAW / SAWTOOTH | Sawtooth Wave | Bright, buzzy harmonic content. |
| SQR / SQUARE | Square Wave | Alternates high/low; hollow timbre. |
| PULSE | Pulse Wave | Variable-width square wave. |
| SUB | Sub-Oscillator | Output one or more octaves below the main oscillator. |
| NOISE | Noise Generator | Random signal (white, pink, etc.). |
| PW | Pulse Width | Controls duty cycle of pulse wave. |
| PWM IN | Pulse Width Modulation Input | CV input to modulate pulse width. |
🧠Sequencing & Logic Terms
| Label | Meaning | Description |
|---|---|---|
| SEQ | Sequencer | Outputs a series of voltages over time. |
| STEP | Step | Single stage in a sequence. |
| CLK IN / OUT | Clock Input/Output | Timing sync signals. |
| DIV / MULT | Clock Divider / Multiplier | Alters clock rate by ratio. |
| RND / RANDOM | Random Output | Generates random voltages or triggers. |
| LOGIC | Logic Functions | Combines triggers (AND, OR, XOR, etc.). |
| GATE OUT | Gate Output | Sends gate signals per step or event. |
🎚️ Filter & Effect Terms
| Label | Meaning | Description |
|---|---|---|
| CUTOFF | Filter Cutoff Frequency | Frequency where filter begins attenuating. |
| RES / RESO / Q | Resonance | Emphasizes frequencies near cutoff. |
| HP / HPF | High-Pass Filter | Removes low frequencies. |
| LP / LPF | Low-Pass Filter | Removes high frequencies. |
| BP / BPF | Band-Pass Filter | Passes a mid-frequency band. |
| NOTCH | Notch / Band-Stop Filter | Removes a narrow frequency band. |
| DRY / WET | Dry/Wet Mix | Balance between original and processed signal. |
| FB / FEEDBACK | Feedback | Amount of output fed back into input. |
| DELAY / REVERB | Delay / Reverb | Time-based effects. |
⚙️ Utility and Misc Terms
| Label | Meaning | Description |
|---|---|---|
| ATT / ATTENUATE | Attenuator | Reduces signal level. |
| OFFSET | DC Offset | Adds a fixed voltage. |
| INV / INVERT | Inverter | Flips signal polarity. |
| MIX / SUM / ADD | Mixer | Combines voltages or audio. |
| MUTE | Mute | Silences signal. |
| PAN | Panning | Controls left-right balance. |
| LEVEL / VOL | Level / Volume | Output gain control. |
| BI / UNI | Bipolar / Unipolar | Indicates whether a signal swings around zero (bipolar, e.g. –5V to +5V) or only stays positive (unipolar, e.g. 0V to +5V). Bipolar signals can modulate parameters both above and below a center point, while unipolar signals only add or increase values. |
| LIN / EXP | Linear / Exponential | Response curve type (VCAs, envelopes, etc.). |
| EXP FM / LIN FM | FM Type | Specifies exponential or linear frequency modulation input. |
đź’ˇ Power and Connectivity
| Label | Meaning | Description |
|---|---|---|
| +12V / -12V / +5V | Power Rails | Eurorack standard supply voltages. |
| GND | Ground | Common voltage reference. |
| BUS | Bus Connection | Shared power or CV bus line. |
| MIDI / USB | Connectivity Ports | Digital communication or control interfaces. |