s3g-dsp

Panner LBAP

s3g Panner LBAP is a direct speaker panner, not an ambisonic plugin. It forms local gain lobes from the layers and neighborhoods of the selected speaker layout.

Panner LBAP with four source points and its cyan solver topology across the Icosahedron 20 speaker geometry in a three-quarter view.

Workflow

  1. Insert Panner LBAP on a REAPER track with the required source inputs and enough channels for its 64-channel output bus, then select or load the speaker layout and confirm its active speaker count and output order.
  2. Route the active output lanes to the matching main speakers, directly or through a speaker-array utility chain, then begin playback.
  3. Move sources in FIELD and adjust FOCUS while watching the cyan solver-topology overlay.
  4. Check transitions between speaker tiers, around the poles, and through any unsupported elevation region before final calibration.

Signal Shape

source inputs
-> source azimuth / elevation / distance
-> layout layers and local speaker neighborhoods
-> normalized LBAP lobes and pole support
-> source distance rolloff
-> speaker outputs 1-64

Only the active speaker count writes sound. Unused output lanes are silent.

Layer and Local-Lobe Panning

LBAP measures a source against the local azimuth and elevation spacing around each speaker. A speaker receives energy while the source remains inside that local lobe, then hands the source to neighboring speakers as it crosses the layout. FOCUS changes the lobe curve: lower settings make broader overlaps, while higher settings concentrate energy more tightly around the matching speaker directions.

The gains are power-normalized after the local lobes are calculated. This keeps the directional distribution controlled while allowing the topology of uneven rings, stacked tiers, and partial three-dimensional arrays to shape the transition.

Solver Topology

The faint cyan overlay is the topology LBAP uses to understand speaker neighborhoods. It is not merely a decorative nearest-neighbor drawing. Imaginary solver speakers may appear where a layout needs support, but they do not add output channels.

Flat layouts receive silent imaginary top and bottom support. Moving away from the speaker plane then produces a smooth level change instead of treating elevation as unused. Partial three-dimensional layouts can receive pole-cap blending so motion remains stable near +90 and -90 degrees.

Speaker and Source Distance

LBAP steering follows azimuth, elevation, and angular topology rather than the stored radial distance of each speaker. A source at DST 1 can therefore be directionally aligned with a farther Cartesian cube speaker even when the two markers do not overlap. See AED Distance and Layout Shape for the preset geometry.

Source DST still controls overall rolloff and the selected IN behavior. For flat layouts, elevation also contributes a smooth attenuation away from the speaker plane. When a layout has no real lower speakers, downward motion preserves the LBAP distribution and rolls toward silence at -90 degrees.

Field, Mixer, and Design

FIELD shows sources, speaker geometry, and the cyan LBAP topology. MIXER provides source gain, mute, solo, and output level. DESIGN edits or imports speaker positions. These pages and the custom-layout JSON format are shared with Panner Layout; see Pages, Design Page, and Custom Layout JSON.

The host project stores the selected TOP, SIDE, or 3/4 view together with manual rotation and zoom.