Sound, radio and light aren't three transmission methods — they're three rungs of one fold-rate ladder, crossing a substrate boundary at the κ-line. A build is a fold-pattern; one encode voices it on any rung. Proven round-trip on all three — right here in your browser.
§0 · the ladder — one axis of fold-rate
above the κ-line the fold vibrates the FIELD (crosses vacuum, needs no medium) · below it, MATTER (needs a medium, dies in vacuum) the vacuum sorts the ladder: the source survives, the downstream needs matter — the Perseus cluster hums a real B♭, 57 octaves below middle C