A declarative send matrix description: a cross-product of source kinds → destination
kinds (a cross-point exists when the source is one of from, the destination one of to,
and both are real channels present in the topology). Omitting from defaults it to inputs;
omitting to defaults it to every audio-bus kind present. Passing a bespoke
SendMatrixSpec instead covers a desk whose routing is genuinely asymmetric (Midas),
and the literal 'none' builds a matrix with no cross-points (the software mixer, mock,
fake host — routing lives elsewhere).
A declarative send matrix description: a cross-product of source kinds → destination kinds (a cross-point exists when the source is one of
from, the destination one ofto, and both are real channels present in the topology). Omittingfromdefaults it to inputs; omittingtodefaults it to every audio-bus kind present. Passing a bespoke SendMatrixSpec instead covers a desk whose routing is genuinely asymmetric (Midas), and the literal'none'builds a matrix with no cross-points (the software mixer, mock, fake host — routing lives elsewhere).