Ambi Encoder Membrane Kick

Ambi Encoder Membrane Kick is a deep, pitch-dropping bass-drum synthesizer whose spatial field comes from the vibrating body itself. Twelve shared modes are sampled at sixteen positions on one membrane; those positions can radiate from different directions in selectable first-, second-, or third-order ACN/SN3D, appear directly as sixteen ordinary pickup lanes, or fold down to stereo. The result is one coherent strike that can bend across encoded space or be routed from its physical sampling points.

Its low-end voicing draws broadly from high-output subwoofer, car-audio, and sound-system listening contexts while remaining a general membrane source rather than a model of a particular enclosure, vehicle, or listening position.

s3g Ambi Encoder Membrane Kick 16 is a fixed-width member of the Ambi Encoder family.

Workflow

1. Set the track to 16 channels, insert s3g Ambi Encoder Membrane Kick 16, and choose 1OA, 2OA, 3OA, 16 PICKUPS, or STEREO DOWNMIX from FORMAT.
2. Follow an ACN/SN3D format with an ambisonic decoder. Route 16 PICKUPS as ordinary lanes instead. STEREO DOWNMIX is ready for an ordinary stereo path on channels 1–2.
3. Send MIDI notes, press STRIKE, or click the membrane display. Leave MIDI RECEIVE on OMNI, or choose CH 1 through CH 16 when several instruments share a MIDI stream. Open the membrane STRIKE page to automate X and Y, or choose a randomized placement mode.
4. Set TUNE for the settled low frequency, then balance DROP, TIME, and PUNCH for the attack trajectory.
5. Choose a membrane SHAPE and raise AMOUNT. Shape changes the modal tuning and the distributed surface coordinates together.
6. Use SPREAD, DEPTH, and ROTATE to place the complete membrane in the ambisonic field.

Signal Flow

1. A MIDI note or editor strike applies one force at the selected X/Y point. Velocity changes the accepted force according to VELOCITY.
2. The force excites twelve modal identities. DROP and TIME move their shared frequency scale rapidly toward TUNE; DECAY and DAMP remove energy from the complete body.
3. Each mode is sampled at sixteen surface patches. Off-center strikes produce asymmetric mode weights, while a central strike emphasizes the fundamental.
4. Each patch is saturated before encoding. DRIVE therefore changes the local membrane radiation without independently clipping ambisonic channels.
5. The selected FORMAT encodes the patches from their shaped coordinates, places pickup P1–P16 directly on channels 1–16, or pans and sums those pickups onto stereo channels 1–2. A linked final guard applies one gain to the complete frame so the field or pickup balance remains intact.

Shape and Strike Position

CIRCLE begins with the familiar split modal pairs of a symmetric membrane. ELLIPSE separates the horizontal and vertical pairs, SQUARE moves toward rectangular mode relationships, TRIANGLE creates threefold geometry, and IRREGULAR removes the remaining degeneracies. AMOUNT interpolates from the circular body toward the selected shape.

The editor draws the active outline, the sixteen radiation patches, and the current strike crosshair. Moving the crosshair changes which modes accept the impact: central positions favor the long fundamental, while edge positions bring more asymmetric overtones and stronger directional change.

The membrane panel has BODY and STRIKE pages. On STRIKE, X and Y are ordinary automatable CLAP parameters. MODE: FIXED follows those coordinates, RANDOM AREA chooses a new position across the usable surface for every hit, and RANDOM RIM chooses a new position in an outer annulus to emphasize asymmetric upper modes. The placement mode is also automatable. The crosshair shows the position actually used by the most recent hit, including randomized hits.

Clicking the membrane is a direct performance gesture: it switches placement to FIXED, writes the chosen X/Y position, and triggers the body.

Deep Bass Controls

TUNE is the frequency reached after the pitch drop. The default 43 Hz body sits in the low-bass range; DROP starts the modes above it and TIME controls how quickly they fall. PUNCH adds force to the fundamental, while CLICK adds a short high-passed impact localized near the strike point. Higher DAMP values shorten upper modes more strongly than the fundamental.

MIDI Behavior

Every accepted note-on strikes the shared membrane; note-off is ignored because the body rings naturally. MIDI RECEIVE defaults to OMNI. Choose CH 1 through CH 16 to accept only that channel from either CLAP note events or ordinary MIDI note-on messages. Editor strikes remain available regardless of this setting.

TRACK defaults to 100%, so MIDI note 36 plays the frequency set by TUNE and every semitone transposes the complete membrane chromatically. Lower TRACK for partial tracking, or set it to 0% when every key should play the same kick pitch.

VELOCITY also defaults to 100%. Note-on velocity scales the modal force, fundamental punch, and localized click together, so soft notes produce genuinely softer membrane motion rather than only turning down the output afterward. Lower VELOCITY to compress the performance dynamics. The instrument is one shared physical body rather than a polyphonic bank, so a new hit adds energy and restarts the global pitch trajectory.

Factory Presets

Click the title-band PRESET field to open the fourteen-voice factory bank. A factory choice changes the membrane voice and spatial radiation while preserving the current FORMAT, OUT trim, and MIDI RECEIVE routing. RANDOM chooses another factory voice; LOAD and SAVE continue to use complete user-state preset files.

The final five presets are sound-system-informed translations made entirely with the existing membrane controls. They do not model a particular cabinet, crew, crossover, horn, delay line, or listening environment.

Controls

Format and Routing

In the three encoded formats, output is ACN/SN3D. Place compatible Ambisonic effects between the instrument and decoder only when their supported order and channel count match the field.

16 PICKUPS bypasses the ambisonic basis and its SPREAD, DEPTH, and ROTATE controls. It exposes each post-drive membrane sample before ambisonic normalization while retaining OUT and the linked final guard. P1–P4 are the inner cardinal ring, P5–P8 the middle-inner diagonal ring, P9–P12 the middle-outer cardinal ring, and P13–P16 the outer diagonal ring; each pickup number maps to the same-numbered output channel. The display labels these points whenever direct format is active.

STEREO DOWNMIX folds the same post-drive pickups onto channels 1–2 with equal-power panning from each pickup's horizontal membrane position and power normalization across all sixteen sources. It bypasses SPREAD, DEPTH, and ROTATE, retains OUT and the linked final guard, and clears channels 3–16. Because this is an ordinary stereo signal, do not follow it with an ambisonic decoder.

Listener-Model Boundary

Membrane Kick deliberately has no internal Listener Mode. Its modal body, fixed or randomized strike placement, and pre-output HOA field remain open-loop so enabling or disabling an analysis layer cannot alter the source tone, transient, or CPU path. This keeps the instrument predictable for low-frequency work and makes FIXED placement sample-repeatable.

Vehicle-, room-, and seat-dependent listening remains appropriate as a downstream renderer or monitoring model: Membrane Kick supplies the distributed source, while another stage supplies the environment and listener transfer path.

Limits

The shape families are musical modal approximations, not finite-element reconstructions of calibrated drum shells or heads. The instrument does not accept audio input and does not follow host tempo. Its shared-body retriggering is designed for kick and tom gestures rather than independent overlapping pitched voices. See Modal Synthesis and Physical Modeling for related membrane and resonator references.