TT-KICKSHAPE — User Manual

01The concept

A compressor-based sidechain reacts to a signal and needs threshold, ratio, attack and release to approximate the shape you actually want. TT-KICKSHAPE skips the approximation: you draw the volume curve, and the plug-in plays it back every time it is triggered. The result is the same as a perfectly tuned kick sidechain — or a trance gate, an offbeat duck, a swell, a tremolo — with exact timing and no detector in the way.

trigger  →  curve phase 0..1  →  c = curve(phase)
gain = max( 1 − DEPTH · (1 − c'), floor )     c' = c, or 1 − c with INVERT
gain → 1-pole SMOOTH → multiplies the signal (or one band, or a low-pass cutoff)

02Quick start

1. Insert TT-KICKSHAPE on the track that should pump (bass, pad, bus). A new instance starts in BEAT mode with the preset Classic Pump on a quarter-note grid: press play and the track ducks on every beat.
2. Pick another shape in the preset bar in the header (arrows, or click the name for the list) or draw your own: click on the curve to add a point, drag points, right-click a point to delete it, Alt-drag or double-click a segment for its tension.
3. Set the length with RATE (1/32 … 8 bars, triplets and dotted values). DEPTH scales the effect, SMOOTH rounds sharp edges against clicks.
4. For a sidechain from a kick track instead of the beat grid: switch to MIDI (a note-on restarts the curve) or AUDIO (a transient does).

03Trigger modes

BEAT

RATE is the length of the curve: 1/32T … 1/2 dotted and 1, 2, 4, 8 bars (bars follow the project time signature). OFFSET shifts the grid in sixteenth notes, PHASE shifts the start inside the curve. Changing RATE while playing keeps the phase continuous (measured jump < 1e-13); the grid re-locks at the next play or seek. When the transport stops the phase freezes (so the gain stays where it was); RUN WHILE STOPPED keeps the clock running at the host tempo instead.

MIDI

A note-on restarts the curve at exactly its sample. MIDI CH and NOTE filter which notes count (ALL = any). Note-offs are ignored: the curve runs out to its end value and stays there until the next trigger. The curve length is LENGTH — a note value (SYNC) or milliseconds (MS). THRU decides whether notes are passed on; controllers, pitch bend and clock always pass. WAIT chooses what a trigger during a running curve does: off = restart at once, on = it is remembered and starts exactly when the running curve ends. Only one trigger is remembered.

AUDIO

A peak at or above THRESH (−60…0 dB) starts the curve. After a trigger the detector is locked for HOLD ms and until its 10 ms envelope has fallen 6 dB below the threshold, so a decaying kick cannot retrigger itself. DETECT ON selects the source: the sidechain pins 3/4, the main input, or AUTO (pins 3/4 as soon as they carry signal). An audio trigger can only fire when the transient has arrived — use LOOKAHEAD (0–10 ms) to delay the audio and start the curve earlier; it reports the delay to REAPER (PDC). Without lookahead the plug-in adds no latency.

FREE

A free-running clock at RATE Hz. The phase restarts at transport play.

04Curve, slots & presets

The editor holds up to 32 points; each segment has its own tension (Alt-drag it up or down, double-click resets). The grid snaps points in time (X GRID: off, 1/4 … 1/32 of the length) and level (Y GRID); hold Shift to place a point without snapping. The vertical line is the playhead. A thin white line shows the effective curve after TENSION, INVERT, DEPTH and MIN LEVEL. The number under the editor is the real gain in dB right now.

Slots A–H each hold a complete curve and are saved with the project (they are part of the plug-in state, so presets you save in REAPER carry all eight). COPY / PASTE move a curve between slots. A preset is a built-in curve that is loaded into the active slot; a star after its name marks a curve you edited since.

The 19 preset curves are the factory list of the preset bar (next chapter); a new instance fills the slots as listed below the table.

Factory presets are code, not saved data: they never overwrite anything you did not load yourself. A new instance fills the slots with Classic Pump, Trance Gate, Sine Wobble, Offbeat Duck, Fast Pump, Reverse Saw, Trap Chop and Sidechain Kick.

05Preset bar & user bank

The bar loads and saves the whole sound of the instance in one step: all timing, shape, stereo, target, band and detector settings plus all eight curve slots with their preset names. Not part of a preset: the colour scheme (OPTIONS), the grid snapping of the editor, the MIDI channel / note filter and THRU, the CC number and channel, RUN WHILE STOPPED and the hidden test parameters.

A factory preset loads a curve into the active slot and leaves every other setting alone (exactly like the old preset selector). A user preset restores everything, including which slot is active and all eight slot curves.

Where the user bank lives. Plug-ins cannot write files, so the 32 user slots are part of the plug-in state: they are saved with the project, with FX-chain and track-template copies, and in every REAPER preset of this plug-in (the + button in the FX window toolbar). To take your bank to another project or computer, save a REAPER preset once (+ → Save preset) and load it there: the whole bank comes with it. Projects saved with earlier versions load unchanged with an empty bank.

Typing names. REAPER keeps Space for the transport, so type Shift+Space for a blank. Depending on your REAPER settings Esc closes the whole FX window; use CANCEL instead. (The + menu of the FX window also has Send all keyboard input to plug-in.)

06Shaping the gain

07Stereo & 3-band split

LINK (default on) gives both channels the same curve. With LINK off, L/R OFFSET delays the right channel’s curve by that share of the length — a ping-pong pump; in MIDI/AUDIO mode the run is extended by the offset so the right channel finishes its curve.

3-BAND SPLIT divides the signal at X1 (40–400 Hz) and X2 (400 Hz–8 kHz) with 4th-order Linkwitz-Riley filters. Each band has its own DEPTH (multiplied by the global DEPTH) plus M (mute) and S (solo). The typical use: duck only the bass region under a kick and leave the top untouched. The low band passes an all-pass at X2, so the three bands add up to a flat magnitude response (measured ±0.013 dB from 60 Hz to 16 kHz; the null test against the input passed through the same two all-passes is −135 dB).

08Low-pass target

TARGET chooses what the curve controls: VOLUME (default), LP FILTER or BOTH. The low-pass is a 12 dB/oct state-variable filter whose cutoff follows the gain: cutoff = FREQ · 2^(−RANGE · (1 − gain)). At gain 1 the cutoff is FREQ; a full dip lowers it by RANGE octaves. At gain 1 the filter is blended out exactly (bit-exact). Beta: the target is verified against the analytic filter response (within 0.1 dB at 1 kHz cutoff), but not yet tuned by ear. With the split on, the low-pass acts on the summed output.

09MIDI CC output

CC OUT sends the current curve value (after DEPTH, INVERT, MIN LEVEL, before SMOOTH) as a controller, 0–127, on CC # / CH. A value is sent only when it changes (at most one per block), so a constant curve sends nothing after the first message. Use it to modulate a synth filter or a send from the same curve that ducks the volume — the LFOTool principle. Measured: value = round(127 · curve) exactly, position and value identical at the receiver. MIDI that enters the plug-in still passes through.

10Latency, routing & lookahead

• The plug-in adds no latency (BEAT, MIDI, FREE; AUDIO with LOOKAHEAD 0). With LOOKAHEAD > 0 in AUDIO mode the audio is delayed by that time and the plug-in reports it, so REAPER realigns everything: the curve then starts 0–10 ms before the transient. In the other modes LOOKAHEAD does nothing.
• Sidechain pins: the plug-in has four inputs; pins 3/4 are the sidechain. Send the trigger track to channels 3/4 of the plug-in’s track (set that track to 4 channels), then pick DETECT ON: SC 3/4 (or AUTO).
• MIDI: feed the note-ons from a MIDI track (MIDI-only send) or the track’s own MIDI input. In MIDI mode, notes are removed from the output unless THRU is on.

11Controls

All sliders are hidden by design; the drawn front (1000×700, scales with the window) is the interface. Knobs: drag vertically, Shift = fine, mouse wheel, right-click / double-click / Ctrl-click = default. Hover any control for a tooltip.

Options / Color. The OPTIONS button at the right end of the header (right of the preset bar) opens the box; COLOR offers ten schemes: ACID, CYAN, ORANGE, MAGENTA, YELLOW, RED, BLUE, VIOLET, MINT and ICE. A scheme changes the accent colour (curve, knob rings, active buttons, LEDs, meters), the second colour and, for RED to ICE, the slightly tinted panel background of the whole front at once. The choice applies per plug-in instance, is saved with the project and with FX-chain copies, and is not touched by preset or slot changes (it is not part of a preset). The factory colour is CYAN. The colour is stored in the hidden parameter 58 (UI Color, 0–9).

12Hidden readouts

Sliders 46–56 (Q IDX … Q CMD) are a test interface used by the regression suite (phase, gain, trigger and CC logs, slot checksums); PRESET LOAD (slider 44) is a momentary parameter that loads a factory curve into the active slot and jumps back to 0 (for automation). Slider 58 (UI Color) stores the colour scheme of the OPTIONS box. None of the other sliders are needed in normal use.

13In practice

• Kick sidechain on the beat: BEAT, RATE 1/4, preset Classic Pump or Sidechain Kick 4/4 (RATE 1 bar), DEPTH 70–100 %, SMOOTH 1–3 ms.
• Kick sidechain from the actual kick: MIDI mode with the kick’s MIDI on the sidechain track, or AUDIO mode with the kick routed to pins 3/4, LENGTH 1/4 or 300 ms.
• Trance gate: BEAT, 1 bar, Trance Gate 1/16, MIN LEVEL −inf, SMOOTH 1 ms; L/R OFFSET 25 % with LINK off for stereo movement.
• Duck only the low end: 3-BAND SPLIT on, LOW 100 %, MID 30 %, HIGH 0 %, X1 around 200–300 Hz.
• Modulate a filter with the same curve: CC OUT on CC 74, map it in your synth.

14Troubleshooting

• The gain stays low while the transport is stopped — BEAT freezes the phase; enable RUN WHILE STOPPED or use FREE.
• Nothing happens in MIDI mode — check the channel / note filter (ALL), that notes actually reach the track, and that MIDI CH counts channels 1–16.
• AUDIO mode fires too often or never — raise or lower THRESH, raise HOLD; with a sidechain send use DETECT ON: SC 3/4.
• Clicks on hard edges — raise SMOOTH (1–3 ms is usually enough).
• Gate presets look rounded — the editor draws the drawn points; the playback curve is a 8192-step table, so an edge is up to 0.012 % of the length wide.
• The three bands do not sum to the input — expected, see “good to know”: the sum is an all-passed copy (flat magnitude).