Processor Ambi Imprint

s3g Processor Ambi Imprint 64ch applies a designed directional space response to a first-through-seventh-order ACN/SN3D field. It loads .s3gimprint files exported directly by the browser-based s3g-mc Imprint Sketch utility.

Workflow

Insert s3g Processor Ambi Imprint 64ch on a correctly routed Ambisonic track after the encoder or encoded source and match ORD to the field.
Follow it with an ambisonic decoder. Additional Ambisonic effects may be placed before the decoder when their supported order and channel count match the field.
Select a bundled ATLAS response or use LOAD to open a custom .s3gimprint file.
Raise MIX from dry, then refine focus, width, field listening, and output level while audio is playing.

Signal Model

The 64-channel input remains available as the full-order dry field. The wet path samples the field through four or eight symmetric directional probes, routes each discrete early reflection toward its two nearest output probes, convolves the late response, and re-encodes the bank into the selected output order. This gives the response a deliberately lower spatial rank than the dry source, which suits reflected and diffuse energy while retaining project routing through a fixed 64-channel bus.

Field Listen lets that re-encoded wet field listen to itself. A bank of profile-aligned virtual microphones analyzes the ACN/SN3D field directly—there is no intermediate loudspeaker decode—and its slow envelopes continuously reshape the profile gains. This is control feedback rather than an audio feedback loop: the heard field changes how the next field is formed, but samples are not recirculated into the convolution input.

The file stores timing and spectral descriptors rather than sample-rate-specific FIR arrays. When an imprint is loaded, the plugin prepares convolution kernels for the host sample rate. Responses are limited to four seconds and the plugin reports 1024 samples of latency.

Imprint Sketch can describe connected wall, overhead, beneath, and stacked regions joined by rectangular, arched, circular, elliptical, slot, or irregular portals. Their path timing and directional loss are resolved into the loaded response profiles; the optional region graph drives the plugin's orbitable geometry display.

Low-Frequency and Gain Safety

The wet excitation path includes a fixed 25 Hz high-pass filter that removes DC and subsonic energy before the directional probes. Every first-order component uses the same filter response, and all subsequent safety gain is linked across the ambisonic field, so protection does not independently reshape channels or move the apparent image. The latency-aligned dry path remains unfiltered.

When an imprint is loaded, direct and sparse early-reflection taps receive a shared transfer-gain budget capped at +6 dB. Dense echo files therefore retain their relative timing, direction, and decay pattern without allowing hundreds of positive taps to create extreme low-frequency gain. A fast linked wet-field limiter provides a final guard before Mix and Output; user Output gain remains available after that guard.

Controls

Control	Meaning
ATLAS	Loads one of nineteen bundled spaces spanning architecture, caves, caverns, tunnels, canyons, clearings, structured echoes, and abstract networks.
LOAD	Selects an Imprint Sketch `.s3gimprint` file.
TOP / SIDE / 3/4	Set exact camera views. Drag the field to orbit and use the wheel or `-`/`+` controls to zoom. Camera state is saved with the project.
ORD	Selects first through seventh order; inactive higher channels are cleared.
MIX	Blends the latency-aligned dry field with the convolved field.
FOC	Changes how strongly first-order direction contributes to the response probes. At zero, the wet bank follows omnidirectional energy.
WID	Scales higher orders in the re-encoded wet field.
LST	OFF leaves the imprint fixed. FOL reinforces profiles heard strongly in the wet field. CTR transfers that tendency toward opposing directions. BAL applies slow negative feedback to restrain dominant directions. Source markers grow with detected activity and show their current gain multiplier.
OUT	Output trim.
BYP	Smoothly returns to the latency-aligned dry field.

Imprint Atlas

The bundled atlas contains nineteen deterministic, precomposed spaces. It includes conventional rooms, contrasting natural enclosures, open spaces, coupled passage systems, five geometry-derived echo designs, and mixed impossible networks. Atlas selections are processed in the same way as imported .s3gimprint files.

Creating Custom Imprints

Open the s3g-mc Imprint Sketch browser utility to generate, mutate, design, or import an editable space project. Choose Export Imprint, then load the resulting .s3gimprint file in Processor Ambi Imprint.

The imported descriptor is embedded in CLAP project state, so reopening a REAPER project does not depend on the original file remaining at the same path. The format reference documents the versioned interchange contract.

The plugin does not need to load a separate glTF file for display. It renders the primary polygon, ceiling profile, connected-region geometry, listener, and directional sources carried by .s3gimprint. Use Imprint Sketch's glTF export for interchange with dedicated 3D software.