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 analyzes 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 on the plot 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 onto a shared bus, so you can sidechain any track in any DAW. With Orra Link 2 senders, tracks appear in the trigger-source menu by name, with their track color.v1.1.0 Drop Orra Link on a vocal and "Lead Vox" shows up in the Ducker's Source menu ready to pick. The trigger can be the plugin's own input, the host's external sidechain bus, or any Link track, so you can key the ducker from any track even in hosts whose routing won't normally allow it.

This manual runs front-to-back. Start with the Interface Tour, read How Spectral Ducking Works for the one concept that makes the rest obvious, then skim The Controls. The later chapters cover latency modes, the analyzer, sidechaining with Orra Link, and a workflow tips section.

The window is organized 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.

It is worth thirty seconds on the core idea, because the rest of the plugin follows from 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.

Eleven 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 in the header 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 center 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 to 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 four traces

Toggle any trace on or off with the IN / SIDE / OUT / DUCK buttons on the riser. A legend in the top-right of the plot lists whatever is currently shown.

The reduction scale

The focus handles

The two gold circles sitting on the plot are the LOW CUT and HIGH CUT handles. Drag them left and right to set the frequency range the ducker is allowed to work in; the area outside the band dims to show it passes through untouched. They are the same two parameters as the LOW CUT / HIGH CUT knobs on the FOCUS card, so move either and the other follows. Dragging writes proper automation, so you can record focus sweeps.

Per-trace display settings

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 to 60 Hz). These are purely cosmetic. They change how the spectrum is drawn, never how the audio is processed. Turn Smooth up for a clean overview, down to see fine detail.

The SIDECHAIN card's Source dropdown chooses what drives the duck. Four 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 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.
• Orra Link tracksv1.1.0, every track in the project carrying an Orra Link 2 sender, listed in the menu by name with a swatch in its track color. Pick the track and the Ducker follows it wherever it goes: the pick is remembered by name, so it survives session reloads and channel reshuffles. If the source disappears (the Link instance is removed or its track deleted) the picker face shows a dimmed warning next to the name, flagged as "! Name", and the ducker gracefully falls back to self-detection until it returns.
• Link channels, the numbered Link 1 to 36 slots, in a submenu listing only the channels currently broadcasting.v1.1.0 This is the classic numbered workflow, and it is also how senders from the original Orra Link plugin appear. Both generations work side by side.

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.

Stacking instances

Because Orra Link feeds independent sidechain sources, you can place several instances of Orra Ducker on a single track, each reading a different Link track or 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, add three instances of Orra Ducker to the track you want to carve, and point each instance at a different source. Each one runs its own spectral detection independently.

Orra Link is a small sender plugin that ships alongside Orra Ducker, and is shared with the other compatible Orra plugins (Orra EQ, Orra Press, and Orra Space). It broadcasts a track's audio onto a shared bus that every one of them can read, along with the track's name and color, which is how sources show up by name in the Ducker's Source menu.v1.1.0

Assign a numbered channel for the classic Link 1 to 36 workflow, or just let the track publish under its own name. A SEND toggle mutes the broadcast at the source, and an OUTPUT gain stages the trigger feed alone. It changes only what Orra receivers hear, never the source track's own audio.

During an offline render, Orra Ducker validates every Link read against the render timeline. A full-mix bounce, where the Link sender's track renders in the same pass, keeps the ducking sample-accurate.

A solo-track commit or freeze is different: the host renders only the committed track, the Link sender never runs, and no plugin can conjure the missing trigger audio. In that case Orra Ducker automatically falls back to the External (DAW) sidechain bus if you have one routed, and otherwise ducks nothing rather than guessing from stale audio.