Changelog

1.0.6

Bug Fixes

• Fixed Vector3.Distance(origin, origin) always returning 0 in multizone blend calculation — blend ratio now correctly scales with the open space distance (20%–40% range)
• Fixed FindShipLoop coroutine leaking on OnDestroy — coroutine reference is now stored and stopped properly
• Fixed PropagationEngine static event duplicate subscription on scene reload — events are now unsubscribed before re-subscribing in Awake()
• Fixed cumulative volume attenuation bug — AudioSource.volume is no longer multiplied cumulatively on each Play() call. Original volume is preserved and occlusion is applied as a ratio against it
• Fixed EntranceTriggerHook silently failing when LC updates rename internal fields — now tries multiple field name candidates and logs a clear warning if none are found

Improvements

• PlayerTracker reflection search now has a hard limit of 20 attempts — prevents infinite retry loop in edge cases
• EntranceTriggerHook now also checks NonPublic binding flags for isEntranceToBuilding — improves compatibility with future LC builds
• HRTFController is now properly registered as a component on startup (was defined but never attached)
• DebugMode config description updated to accurately reflect its current behavior (verbose BepInEx logging)

Code Cleanup

• Removed dead DoScan() method from RoomAnalyzer
• Removed unused IsInsideFacility property from PlayerTracker
• Removed unused LC_ENTRANCE_TRIGGER constant from PlayerTracker
• Removed DebugHUD.cs — HUD rendering was abandoned; file has been deleted

1.0.5

New Features

• Multizone blending — when standing near a doorway or spatial boundary, Project Echo now detects both the near and far spaces and blends their reverb profiles (65% primary / 35% secondary). Transitions between rooms feel natural instead of snapping.
• Reflection material filtering — virtual early reflection sources now apply per-material EQ to the reflected audio:
  • Metal / Glass → high-pass emphasis, bright and sharp ringing
  • Concrete / Brick → neutral reflection
  • Carpet / Dirt → low-pass heavy, dark and muffled reflection

Optimizations

• AudioFilterController.Update() now skips entirely when the source is not playing (isPlaying check) — sources at rest cost zero CPU
• Lerp settlement detection: once all filter parameters reach their targets, _settled = true stops Update() from running until new values arrive
• AudioSourceClassifier cache is now permanent per-scene instead of 30-second TTL — reflection-based lookups happen only once per source per scene
• OcclusionProcessor adds a frame-level shared cache — duplicate raycasts for the same source within the same frame are eliminated
• FilterPool access time is only written back when 0.5s has elapsed — reduces unnecessary dictionary writes

1.0.4

New Features

• Sound source categorization — all AudioSource instances are now classified into 7 categories (Footstep, Monster, Machine, Walkie-Talkie, Player, Ambient, General). Each category receives different reverb multipliers, decay times, and occlusion strength:
  • Machine / Ambient: longer reverb tails to fill the space
  • Footstep: shorter reverb, low-pass HPF disabled to preserve floor thud
  • Monster: occlusion strength ×1.3 — stays audible but muffled through walls
  • Walkie-talkie: no reverb, band-limited to 300–3400 Hz
• Precise air absorption (ISO 9613-1 approximation) — distance-based HF roll-off now uses a squared curve instead of linear. Far sounds lose their high frequencies first; low frequencies travel further, matching physical reality.
• DecayHFRatio dynamic calculation — each room scan now computes a weighted average HF decay ratio from wall materials:
  • Metal / Glass → 1.9 (HF decays slowly → bright ringing)
  • Concrete → 0.6 (HF decays fast → dark, heavy tail)
  • Carpet → 0.2 (near-dead, HF absorbed almost instantly)
• MaterialHardness + AudioHighPassFilter — a per-source HPF is attached and its cutoff/resonance is driven by surface hardness. Hard surfaces produce bright, sharp early reflections; soft surfaces produce none.
• Wet/Dry dynamic ratio — dryLevel and reverbLevel now scale with room volume. Small rooms are direct-sound dominant; large caverns fill with reverb.
• Directional early reflection simulation — a virtual AudioSource is placed at the nearest wall reflection point and plays the source clip at low volume with a PlayDelayed(distance / 343f) offset, giving early reflections a physical direction.

Fixes

• Removed the dead var primaryProfile = yield return StartCoroutine(...) line in RoomAnalyzer that caused a CS1002 build error

1.0.3

New Features

• First-spawn instant scan — RoomAnalyzer now waits for the player to reach a valid position and fires an immediate scan on first spawn, eliminating the reverb-less window after map entry
• Facility entrance/exit detection — EntranceTriggerHook patches EntranceTeleport.TeleportPlayer(). Entering the facility triggers an instant ForceScan(); exiting forces the Outdoor profile with a 3× speed transition blend
• Ceiling height correction — the room scan extracts ceiling distance from the upward raycast. Low ceilings (< 3 m) shorten RT₆₀ × 0.75; high ceilings (> 6 m) extend it × 1.25
• Corridor shape detection — if one horizontal axis is more than 3× longer than the other, the space is classified as a corridor. Diffusion is reduced and RT₆₀ shortened to produce a flutter-echo character
• Floor material weighting — a dedicated downward raycast samples the floor material at ×2 weight in the Sabine calculation, since flooring has the largest acoustic influence in a real room

Fixes

• SpatialAudioManager.IsAlive() static method added — replaces Instance == null checks in ProjectEchoPlugin and SceneHook to avoid triggering the null-warning log on legitimate startup paths
• Ship interior (HangarShip collider) is now detected at runtime; when the player is inside, the ShipInterior preset is forced regardless of scan results
• Wall layer detection now logs the resolved layer names on startup for easier debugging

Config

• New entries in ProjectEcho.cfg:
  • ReverbIntensity (default 1.0) — reverb strength multiplier
  • OcclusionStrength (default 1.0) — occlusion LPF depth multiplier
  • RoomTransitionSpeed (default 3.5) — room blend speed
  • DebugMode (default false) — reserved for future use

1.0.2

• Fixed reverb effect being barely noticeable due to incorrect layer mask
  • "Wall" layer does not exist in Lethal Company — switched to actual LC layers (Default, Room, Colliders, etc.)
• Fixed most in-game sound effects being skipped by the spatial hook
  • LC sets many AudioSources to spatialBlend = 0 (2D) — non-BGM/UI sources are now forced to 3D
• Significantly increased reverb intensity across all room presets
  • room and reverbLevel values were too low to be audible in-game
• Fixed [SAM] Instance not yet initialized warning on startup
  • SceneHook.Register() was being called before SpatialAudioManager was created
• Trigger an immediate room scan on scene load for faster reverb response on map entry

1.0.1

• Fixed CS8618: uninitialized non-nullable fields across multiple files
  • Fields set in Awake() / Bind() marked with = null!
  • Fields that can genuinely be null marked as nullable (?)
• Fixed CS0120: AudioListener.transform called in a static context (HRTFController)
  • Replaced with FindObjectOfType<AudioListener>() with caching
• Fixed CS0070: PropagationPortal calling event.Invoke() from outside the declaring class
  • Added RaisePortalRegistered() / RaisePortalUnregistered() relay methods to PropagationEngine
• Fixed CS8600: PropagationPortal best = null assigned to non-nullable type
• Fixed CS8603: FilterPool.GetOrCreate() returning null from a non-nullable return type

1.0.0

• Initial release
• Real-time RT₆₀ reverb calculation using Sabine's Formula
• Physical occlusion with Low-pass filter
• Portal-based sound diffraction (doors and windows)
• HRTF spatialization with elevation and azimuth tonal shaping
• Low / Medium / High quality tiers
• Automatic low-end detection — systems with under 4 GB RAM default to Low tier