settled-reach/docs/assets/audio/sfx.md

SFX — Audio Assets

World sound effects: footsteps, environmental events, impacts. Event-driven, often positional (AudioStreamPlayer2D).

Generation Approach

Mixed methods depending on duration and character:

• Footsteps: SAO generation (>200ms) or hybrid (generate longer clip, extract best transient)
• Future environmental SFX (doors, machinery events): SAO or foley recording
• Post-processing: normalize, trim, ensure clean attack/release

Assets

ID	Filename	Status	Bus	Method	Duration	Prompt/Notes	Sprint
SFX-001	sfx_footstep_metal_walk.ogg	done	Player Actions	SAO hybrid	0.3s	Single footstep on metal grating. Walk pace. SAO 5s/100 steps/CFG 8, best transient trimmed at 2.42s, LUFS -16 normalized.	S10 #327
SFX-002	sfx_footstep_metal_run.ogg	done	Player Actions	SAO hybrid	0.3s	Faster footstep, sprint pace. Louder — player is broadcasting position (D-053 acoustic footprint). SAO 5s/100 steps/CFG 8, best transient trimmed at 1.03s, LUFS -16 normalized.	S10 #327
SFX-003	sfx_npc_murmur.ogg	done	World SFX	SAO	5s	NPC proximity conversation murmur. Human voices in adjacent room, direction and cadence distinguishable, words not. Organic family. SAO 5s/100 steps/CFG 8, LUFS -16 normalized. Selected from 3 candidates (richest texture).	S13 #532

Detailed Entries

SFX-001: sfx_footstep_metal

• Sonic family: organic (physical world)
• Bus rationale: Player Actions — this is feedback on YOUR movement, not world information. NPC footsteps (future) go on World SFX.
• Stance implications (D-053): Walk = normal volume. Sprint variant (SFX-002) = louder. Careful = quieter variant (future asset). Crouch = near-silent variant (future asset).
• Integration: Triggered by player movement tick. Positional (AudioStreamPlayer2D at player position) — maps to camera-relative stereo per D-018.
• Cross-reference: D-038 (#5), D-053 (movement stances as acoustic decisions)

SFX-003: sfx_npc_murmur

• Sonic family: organic (physical world — human warmth, natural decay)
• Bus rationale: World SFX — this is information about other people in the world, not player feedback. Positional (AudioStreamPlayer2D at NPC cluster position).
• Design intent (D-072): Universal asset — single murmur plays at all NPC proximity events. Zone ambient determines conspicuousness naturally: bar's dense ambient buries it, corridor's sparse ambient exposes it. No zone-specific variants needed.
• Aesthetic (D-074): Organic family. Warm, lived-in, no lattice processing. Mid-freq 200-800Hz texture per station palette "functional warmth" (D-074 conversation murmur band).
• Propagation (D-018): Close range: intelligible as "voices, nearby." Medium range: muffled. Long range: lost in ambient floor.
• Eavesdrop interaction (D-071): Player ListeningFocus boost increases effective reception range. Same asset, confidence varies with proximity and skill.
• Generation: SAO 5s / 100 steps / CFG 8. Prompt: "Warm organic audio, natural sound recording, slight room ambience, lived-in industrial space, realistic acoustic properties, authentic environmental sound. Single isolated sound effect, clean recording, 5 seconds duration, clear attack and natural decay, no background noise, no reverb tail beyond natural. Human voices murmuring through a thin wall or partition, two or three people in low conversation in the adjacent room, words muffled and indistinct, direction and gentle cadence audible, warm mid-frequency vocal texture 200-800Hz, soft intimate conversation murmur, no music, no intelligible words." 3 candidates generated (5s/CFG8, 6s/CFG7, 4s/CFG9). Candidate 1 selected (richest OGG texture, clearest spatial framing). Post-processed: trim, LUFS -16, OGG.
• Integration: Event-driven — fires when player enters NPC cluster proximity range. Not looped continuously; retriggered on proximity events. Loop-capable (5s has natural loop structure) if client opts to sustain during eavesdrop.
• Cross-reference: D-072 (universal murmur decision), D-071 (ListeningFocus eavesdrop), D-074 (organic aesthetic), D-018 (sound propagation model)

Future Expansion

SFX will grow significantly with:

• NPC footstep variants (by surface type, stance) → World SFX bus
• Door open/close, machinery activation → World SFX bus
• Combat impacts, weapon sounds → Player Actions bus
• Environmental events per planet/biome

When this file exceeds ~50 entries, split by domain:

• sfx-movement.md (footsteps, stance variants)
• sfx-environment.md (doors, machinery, weather)
• sfx-combat.md (weapons, impacts)
• sfx-conversation.md (murmur, vocal events)