Additive gong synthesis: seven inharmonic partials with per-partial decay (fundamental 165Hz rings 2.6s, highs die in 0.2s), a detuned pair for shimmer, 45ms distant attack, and three feedback-comb reflections (95/210/370ms, net gain .93) for a dense stone-space tail. Normalized to -12dBFS at codec volume 58: quiet but voluminous. Synthesized into PSRAM at boot (~4s), plays 5s, blocking is fine for bring-up — audio moves to its own task in phase 2. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>