s3g-dsp

Processor Ambi Grain

s3g Processor Ambi Grain 16ch is a CLAP instrument for granulating loaded ACN/SN3D ambisonic files. It treats the file as one encoded sound field: grain position, duration, rate, direction, and envelope are shared across all active ambisonic channels.

Use it when you want clouds, freezes, scans, or stepped cuts from an already encoded 1OA, 2OA, or 3OA file while keeping the spatial image locked together.

Processor Ambi Grain with loaded-field display, grain controls, transport, and ambisonic routing.

Workflow

  1. Insert s3g Processor Ambi Grain 16ch on a correctly routed 16-channel Ambisonic track and set ORD to the intended 1OA, 2OA, or 3OA source order.
  2. 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.
  3. Click LOAD and choose an ACN/SN3D ambisonic audio file.
  4. Use the transport icons to play, pause/resume, or stop and return the scan/grain state to the start.

The output bus is fixed at 16 channels for third-order ambisonics. First-order and second-order modes use the matching lower channel counts and leave higher-order channels silent.

Grain Model

When a file loads, the processor peak-normalizes the complete multichannel field to 0.95 with one shared gain. It never normalizes channels independently, so the ACN/SN3D level relationships and spatial image remain intact.

The processor uses one shared event stream. Each grain reads the same source time across every active ambisonic channel, applies the selected envelope, and writes into a circular multichannel tape layer before output.

This matters for ambisonics: the W, X, Y, Z, and higher-order channels are not independent audio stems. Keeping the grain timing shared helps preserve the encoded spatial relationships while still allowing dense granular motion.

Display

The waveform shows the loaded file as a source-time map. Grain markers show where events are being drawn from, and the jitter window shows the active source area used by modes that randomize grain position.

In SCAN, the source position moves through the file. In FREEZE, grains gather around a fixed source point. In JUMP, source position moves between stepped regions.

Controls

Control Meaning
ORDAmbisonic order to process: 1OA, 2OA, or 3OA.
MODESource-time mode: scan, cloud, freeze, or stepped jump.
DENSGrain density in events per second. Long grain sizes reduce the available density range for stable playback.
GMSGrain size in milliseconds, from short cuts to long 4-second sparse cloud windows.
S-SRCScan source. At 0%, SCAN reads through the full file; above 0%, it scans from the chosen source point.
S-SPDAuto-scan speed used by SCAN when S-SRC is 0%. 1.0x scans through the file at normal timeline speed.
J-SRCJump source used by JUMP mode.
JITSource-position jitter around the current grain position.
RATEGrain playback rate.
RJITPer-grain rate jitter in octave range.
REVChance that a grain reads backward.
F-SRCFreeze source position used by FREEZE mode.
J-STPNumber of source-position steps used by JUMP mode.
SYNCRegular grain spacing or randomized asynchronous spacing around the same density.
ENVGrain window: Parzen, sine, Hann, triangle, or Gaussian.
OUTOutput gain after density compensation.

Routing

Use a 16-channel REAPER track for 3OA work and keep the active channels mapped one-to-one through the decoder. Lower orders occupy the corresponding first 4 or 9 channels while the remaining lanes stay silent.

Playback Guidelines