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Control Types

Every parameter a fusor can modulate is one of two control types, fixed by the parameter itself. A knob or fader is a curve. An enable switch is a gate. You cannot make one behave as the other, and the Domain Editor offers a different set of controls for each.

Which parameters are which is listed in Supported Parameters.

Curves

A curve parameter holds a value between 0 and 1 for every point of the transition. The runtime reads the progress meter, evaluates the curve at that progress, and sends the result.

The shape between two anchors follows the interpolation mode of the anchor on its left: Bezier, Linear, or Hold. The modes, the handles, and what happens at the top and bottom of the canvas are covered in the Curve Editor.

A curve holds between 2 and 16 anchors. The first sits at 0% progress, and on a continuous curve the last sits at 100%.

Unipolar and bipolar

Curve parameters differ in what the middle of the range means:

  • Unipolar. 0 is off or silent, 1 is full. Channel faders, FX amounts and stem levels work this way, and a curve to 0 is how a fusor silences something.
  • Bipolar. 0.5 is unity, below it cuts and above it boosts. EQ bands, stem filters and the Mixer FX Amount work this way, so an EQ curve that should leave a band alone sits flat at the middle of the canvas.

The MIDI values for the same distinction are in MIDI Mapping → Control semantics.

Stepped curves

A curve can be constrained to a small set of named levels, in which case it holds each level until the next anchor instead of interpolating. That is an authoring choice made per binding, either by attaching a step set or by setting interpolation to Hold. See Stepped Output.

Gates

A gate parameter has two positions, Off and On. Fusor Studio uses it for the signal-path enables a knob needs in order to work: Mixer FX Enable, an FX slot enable, a per-stem filter enable, a per-stem FX-send enable.

A gate is authored on the same canvas as a curve, with two differences:

  • The ladder is fixed at two levels. Right-clicking a level lets you rename it. There is no add, no delete, and no step set to attach, change or save, so the property strip's Step Set box is greyed out with Attach… disabled. The point and Edit-curve interpolation menus are never offered, since a stepped lane always holds.
  • Anchors set the timing. Every anchor sits on Off or On, so what you author is when the gate switches. A new gate binding starts Off and switches On at the halfway point. Drag that middle anchor to move the switch point, or add anchors to switch it more than once.

A gate is sent as a MIDI note, on (127) or off (0), so it has no in-between values. See MIDI Mapping → Message types.

What reaches the DJ app

Three things happen between the curve you drew and the message the DJ app receives.

  • Quantization. A continuous value is rounded to one of 128 steps (0–127) before it is sent, so values very close together can produce the same output.
  • Repeat suppression. A value identical to the one already sent for that address is not sent again. A curve sitting flat sends nothing until it moves, and a gate held On sends one message rather than one per tick.
  • Clamping. Values stay inside 0 to 1. The curve you see on the canvas is the value that goes out; see Curve limits.

The Fusor player sets the control to the curve's value. How that sounds depends on the DJ app's mixer settings.

Positions, not decibels

A fusor sends control positions, not levels in decibels. The same fusor sounds different when the DJ app's mixer is set up differently:

  • EQ type. Traktor offers Classic, P600, NUO, Xone, Z ISO and P800; djay offers Classic and Isolator. The same knob position cuts by a different amount in each. In djay, for example, an Isolator band turned fully down is silent, while a Classic band turned fully down is still audible.
  • Filter type. Traktor offers Ladder, Xone and Z.
  • Channel-fader and crossfader curves. A fader at 0.71 is about 3 dB down only when the fader's curve is linear in level.

A fusor's curves are authored for one EQ type, one filter type and one set of fader curves. On a different setup, expect a different result from the same fusor, and adjust its curves to suit.

Read-only addresses

Some addresses in the canonical mapping only ever travel from the DJ app to Fusor Studio. Deck play state is the clearest example. An action step that tries to set one is rejected by name, with the message Cannot SET read-only address "<addr>" (telemetry only). The action fails when it loads, before the transition starts.

The Fusor player also does not control deck transport. You control play, cue and stop.