Orra Ducker User Manual

Orra Ducker is a spectral sidechain ducker. Where an ordinary ducking compressor turns down your whole signal whenever the sidechain is loud, Orra Ducker works per frequency: it analyses the trigger signal across roughly a thousand frequency bins and ducks your audio only where, and only when, the two actually collide.

A kick drum keyed against a bass makes room in the low end without dropping the whole bass line. A lead vocal keyed against a pad carves a pocket in the vocal's range and leaves the rest of the pad untouched.

Everything is driven from one large analyzer. The input, the sidechain, the output, and the live per-frequency gain-reduction curve are all drawn on the same log-frequency display, so you can see exactly what is being ducked and where. Two draggable handles set a focus band, restricting ducking to the range between them so you can aim the effect at just the low end, just the harsh mids, or the full spectrum.

Orra Ducker also reads Orra Link, the companion sender plugin that streams audio from any track in your project into one of 36 sidechain channels. The trigger can be the plugin's own input, the host's external sidechain bus, or any Link channel, so you can key the ducker from any track even in hosts whose routing won't normally allow it.

The window is organised top-down into four horizontal regions, sitting on a brushed-gunmetal faceplate. The header and the control cards are raised out of the plate; the analyzer is recessed into it.

A normal ducker measures one number from the sidechain, its overall level, and uses it to pull down one fader on your signal. Loud kick, whole bass drops. Orra Ducker instead runs a 2048-point FFT (Hann window, 75% overlap) on both the trigger and your audio, splitting each into roughly a thousand frequency bins. Every bin gets its own detector and its own gain computer.

A bin in your signal is only ducked when the matching bin in the sidechain crosses the threshold, so energy in the trigger only carves the part of your signal that shares its frequency. That is why a kick can make space for itself inside a bass without audibly dropping the bass: only the bins the two share get touched.

It is also why the RESOLUTION control matters, it sets how finely the per-bin reduction is allowed to vary across frequency (surgical and narrow, or broad and smooth), which is the difference between a precise notch and a gentle tilt.

Nine controls across three cards, plus the header's latency selector. All knobs are automatable, double-click to default, and double-click-to-type.

The focus band has a soft transition (half an octave) at each edge, so the boundary between ducked and un-ducked is gradual, not a hard wall. With LOW CUT at 20 Hz and HIGH CUT at 20 kHz the whole spectrum is in play.

The LATENCY selector trades spectral precision against reported latency. Bigger FFT frames resolve frequency more finely and duck more precisely, but report more latency to the host. All modes are delay-compensated, so the choice is about tracking feel, not timing.

Selecting a Link sidechain source adds one host block of latency on top of the mode's figure, so the cross-track trigger lines up sample-accurately. The latency read-out beside the selector always shows the true reported total.

The recessed screen is the centre of the plugin, it is how you see the collision between your signal and the trigger, and how you aim the duck. The horizontal axis is log frequency (20 Hz – 20 kHz). It carries two vertical rulers: the left is signal level in dBFS, for the input, sidechain, and output traces; the right, in red, is gain reduction for the ducking trace. They are independent scales: left tells you how loud each frequency is, right tells you how hard the ducker is pulling.

The two gold circles on the plot are the LOW CUT and HIGH CUT handles. Drag them to set the frequency range the ducker works in; the area outside the band dims to show it passes through untouched. Dragging writes proper automation, so you can record focus sweeps.

Right-click the IN, SIDE, or OUT toggle to open a pop-over with two knobs: Smooth (how much the trace is averaged across frequency for a calmer display) and Rate (how often it refreshes, 5–60 Hz). These are purely cosmetic, they change how the spectrum is drawn, never how the audio is processed.

The SIDECHAIN card's Source dropdown chooses what drives the duck. Three kinds of source are available:

• None, the default. The ducker keys off its own input, comparing each bin to the rest of the same signal. Useful for spectral self-leveling and de-masking, though most ducking uses an external trigger.
• External (DAW), the host's dedicated stereo sidechain bus. Route a track to the plugin's SC input in your DAW and it drives detection. The classic setup: send a kick to the sidechain to duck a bass under every hit, except here it ducks only the overlapping frequencies, not the whole bass.
• Link 1 through Link 36, one of 36 sidechain channels fed by the companion Orra Link plugin. Drop Orra Link on any track or bus, pick a channel, and that channel becomes available as a trigger for Orra Ducker anywhere in the project, even in hosts whose routing won't let you sidechain across busses normally.

Whichever source you pick, turn on the SIDE trace to see it on the analyzer in gold. That is the single fastest way to confirm the trigger is arriving and to see which frequencies it will carve.

Orra Link is a tiny sender-only plugin that ships alongside Orra Ducker, and is shared with Orra Press and the rest of the Orra range. It broadcasts a track's audio onto a numbered channel in a shared bus that every Orra plugin in the project can read.

Its controls are a CHANNEL selector (Unassigned, then Link 1–36), a SEND toggle (mute the broadcast at the source without giving up the channel), and an OUTPUT gain for staging the trigger feed without touching the source track's fader. A status pip shows whether the channel is broadcasting.

Because Orra Link feeds 36 independent sidechain channels, you can place several instances of Orra Ducker on a single track, each reading a different Link channel. One track can duck against the kick, the vocal, and the bass at once, with each instance carving only its overlapping frequencies.

Set up Orra Link on each source track (kick on Link 1, vocal on Link 2, bass on Link 3), then add three instances of Orra Ducker to the track you want to carve, and point each instance at a different Link channel as its Source. Each one runs its own spectral detection independently.

The combination of spectral ducking and Orra Link delivers routing flexibility that single-source duckers can't match, and solves a problem that has long made multi-source sidechaining awkward in most hosts.