Patching & signals

A patch is a set of modules joined by cables. A module is one part of the synth, such as an oscillator, a filter, or an amplifier. Each module has jacks along its edges. An output jack sends a signal out of the module, and an input jack takes a signal in. A cable carries a signal from one output jack to one input jack. The studio treats every signal as a voltage. It updates the voltage on each cable once per audio sample.

This guide explains how to make, move, and remove cables, and what the signals on them mean. To pan, zoom, and add modules, see The interface. To build your first patch, see Getting started.

Making a connection

Press on any jack and drag. A preview cable follows your cursor. Release on a jack of the opposite kind on another module to complete the connection. An output always connects to an input, and you can start the drag from either end. Release the cable anywhere else to cancel it. Press Esc to cancel a drag in progress.

A module cannot patch into itself. Two modules can connect to each other in a loop, where a later module feeds a signal back to an earlier one. The studio delays that fed-back signal by one sample so the audio engine keeps running.

Wiring rules

Three rules govern how cables combine:

  • Outputs fan out. One output can feed any number of inputs. To add another cable from a jack that is already connected, press it and drag again.
  • Inputs sum. An input accepts any number of cables and adds their voltages together at full level, so any input can act as a simple mixer.
  • An unpatched input reads 0 V. With nothing patched in, the input contributes nothing to the sum.

Moving and removing cables

You work with cables from the jacks, because the cables themselves are not clickable. To lift a cable off a jack, click that connected jack twice in quick succession. Drag the free end to another jack to re-route the cable, or drop the free end on empty canvas to disconnect it.

Deleting a module removes every cable attached to it. Press Ctrl+Z to bring the module and all its cables back at once.

The four signal types

Every jack carries one of four kinds of signal: audio, V/Oct, gate, or CV. These kinds are a convention. The studio does not enforce them, so any output patches into any input. You can patch an audio signal into a CV input.

The studio uses the same voltage levels as Eurorack hardware synthesizers:

  • Audio is the sound itself, and it swings around ±5 V. Oscillators, samplers, and effects produce audio.
  • V/Oct carries pitch at one volt per octave. 0 V is the note C4. Adding 1 V raises the pitch by one octave.
  • Gates and triggers switch things on and off. A gate holds 0 V when off and 10 V when on, and a trigger is a brief pulse of the same kind. A gate input responds on the rising edge, the moment the voltage climbs to 1 V or higher. A signal that rises past a volt can act as a clock, a steady pulse that sets timing.
  • CV, short for control voltage, adjusts a parameter the way turning a knob would. CV usually runs 0 to 10 V in one direction, called unipolar, or -10 to +10 V in both directions, called bipolar. The LFO outputs either one, ±5 V bipolar or 0 to 10 V unipolar, scaled by its Depth control.

Because every signal is a voltage, the four kinds overlap in use. Run an LFO fast enough and it produces an audible tone. Patch an envelope, a control signal that rises and falls with a note, into a CV input and it works as a slow sweep.

The studio does not color-code jacks or cables by kind. Instead, each module lists its jacks in a fixed order. Inputs run audio at the top, then pitch, then gates, then CV. Outputs list CV before gates. Modules you often wire together line up this way, so their cables cross less often.

Getting sound out

Your patch reaches your speakers or headphones only through an Output module. Patch your final signal into the Output's In L jack. When In R has no cable, it copies In L, so a single cable plays in mono, centered. Patch both In L and In R for stereo.

You can add more than one Output module. They all sum into the single stereo master.

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Tips

  • Build a basic voice. Patch a Keyboard's CV output into an Oscillator's V/OCT input, the Keyboard's GATE output into an ADSR Envelope, and the envelope's output into an Amp's gain CV input. Then patch Oscillator to Amp to Output. Turn the Amp's Gain knob down to 0, because it defaults to 1 and passes sound continuously. Press a key, and the envelope opens the amp.
  • Check a silent patch with a Debug module. Patch it inline on a cable to read the live voltage there. It passes the signal through unchanged, so you can leave it in place.
  • Use input summing on purpose. Patch a Constant into the same V/OCT input as a sequencer. The input adds the two voltages, so the Constant's fader transposes the sequence by one octave per volt.
  • Send one modulator to many destinations. Patch a single LFO output into CV inputs across the patch. An output has no cable limit.