Wire's Acoustics

Sound physics.

Inspired by the video Physically-based audio: why most games sound fake [Voxel Devlog #31], on ray traced audio.

Showcase video

Coming later, sorry lol. If you want, you can record your own, I guess.

How it works

The mod traces rays through the world, the way light is traced in a renderer, but for sound. A few times a second, rays go out from the camera in every direction and find out what's around you: how closed in you are, how big the space is, what it's made of, and where the openings are. Every sound you hear is then shaped by that space and by everything between it and you.

You hear from the camera. Where the camera is, that's where you are.

Wherever I could, the numbers come from real measurements and standards instead of being made up. The sources are at the bottom.

Features

Reverb from the real space

The reverb is worked out from what the rays hit: how big the space is, how closed in, and what it's made of. A stone hall rings, a log cabin sounds warmer, a cave sounds like a cave, and a furnished room is drier than an empty one. Windows, doors and gaps let sound out instead of counting the sky behind them as part of the room. Open ground is dry.

Walls block sound like real walls

Walls, floors, roofs and doors block sound as much as real ones measure, by material and thickness. A wood wall is like a solid timber wall, a door leaks more, stone is like a brick wall. Through a wall you hear a muffled but still recognisable sound, not just a rumble.

Sound goes round things

A sound behind a wall also reaches you through the openings: a window, a door, a hole in the roof, round a corner, or bouncing off a surface. You hear it from where it comes through, so a deer outside is heard at the window much more clearly than through the wall. Going round a corner costs what it really costs, more of the highs the longer the detour. Hills, rocks, trees and furniture in the way muffle by their size: a trunk barely matters, a boulder takes the highs off, a hill cuts a sound depending on how high it rises.

Bounces

Sound reaching you off a wall is as loud as the reflection would really be: what the surface doesn't absorb, mirrored where the angle is right and scattered elsewhere, depending on how rough the material is.

Material matters

Every surface absorbs the lows and highs by published data for what it is. Snow swallows sound, moss and forest floors soften it, grass a bit less, paving and stone reflect it, water reflects almost everything. Just like IRL. Cool, right?

Distance and air

Sounds fade with distance the way real sound does, instead of cutting out after a few metres. The air takes the highs off far sounds as the international standard says it does, with the weather: warm, cold and freezing are matched to the real Norwegian weather Valheim is modelled on.

Wind

Downwind a sound carries a few dB further; upwind it can drop a lot from about 100 m away, as measured outdoors. You also hear the wind in your ears from the way it's blowing.

Sound takes time

Sound travels at the speed of sound. A tree falling far away is heard after you see it.

Doppler

Moving sounds rise in pitch as they come toward you and drop as they go away. Ships' wakes too.

HRTF (headphones)

HRTF stands for head-related transfer function: how your head and ears change a sound depending on where it comes from. A sound on your left reaches your right ear a tiny bit later and duller, sounds behind you lose some brightness, and your outer ear colours sounds from above and below. The mod models this itself, for every sound, so you can tell front from back and up from down, not just left from right. Best with headphones. I'd recommend turning HRTF off on speakers, as your real head already produces ACTUAL HRTF. For the mod's own HRTF to sound its best, turn off Windows Sonic or Dolby Atmos spatial processing on your output device while playing Valheim; running both spatializers together can reduce directional clarity.

Sounds come from where they're made

The game plays a lot of sounds at a character's feet or at the base of a piece. Here, weapon swings come from the weapon and follow the swing, a bow's draw from the bow, holstering from your back, eating from your head. Creatures roar from their head, claw with their arm and stomp with their feet. Chests sound from the lid, fires from the flame, crafting from the station. Anything that moves takes its sounds with it, and big sources (a hearth, a cart, a troll) sound as wide as they look.

Weather and the sea

Indoors, rain, wind and birds come in through the windows and doors from their direction; through closed walls only a faint rumble gets in. The sea is heard from the actual shore and fades like a long shoreline does. Under water, the world above is about 30 dB quieter, as the physics of the water surface says.

Portals

Going through a portal, its hum doesn't stop and restart: it carries through with you and keeps playing from the exit portal. More of an extra than sound physics, but it's audio-related so it's here.

Also

• No pitch drop in the Mistlands mist (fog doesn't do that to sound, and I don't like it).
• The main menu's sounds get the HRTF too. Barely noticeable there, tbh, but it's there.

Works with

• Proximity Voice Chat (Azumatt): voices get the walls, openings and HRTF like any sound.
• Wire's Stackify: its chest sounds come from each chest.
• (kinda) Immersive Weather & Acoustics: set its EnableAudioOcclusion = false so only one audio system runs; its visual weather can stay on.

Performance

The ray tracing runs on Unity's worker threads, and the per-sound processing runs on the audio thread. The game's audio update does a small amount of bookkeeping on the main thread. Paths round walls and second bounces are only traced for sounds that are blocked, and rooms that don't change are scanned less often, with a refresh when something is built, removed or a door opens.

Settings

• General: Enabled, Room reverb, Muffling, HRTF (headphones), Realistic distance.
• Tuning: Reverb strength, Muffling strength, HRTF strength.
• Debug: Debug log: the measured space, muffled sounds and the mod's costs, every few seconds.
• Turning the mod off restores the game's own reverb zones, listener position and sound placement without a reload (for whatever is still loaded).

Sources

• Air absorption: ISO 9613-1, Attenuation of sound during propagation outdoors, part 1. Weather: Bergen (Florida) July and Finsevatn January climate normals, 1991-2020.
• Barriers, corners, hills, obstacles: Maekawa's barrier chart in Kurze and Anderson's formula; capped at 20 dB as in ISO 9613-2.
• Walls and doors: WoodWorks, Mass Timber Acoustics (cross-laminated timber, STC 33 to 38); Commercial Acoustics (solid-core wood door, STC 30 to 35); Engineering ToolBox (brick wall STC 55, and the average shape of a wall's loss over frequency). Iron and ice: the mass law.
• Surface absorption: Sengpiel's table of absorption coefficients; the pyroomacoustics materials database; heyizhou.net's absorption coefficient tables (steel decking).
• Ground: the Nord2000 ground classes (flow resistivity), as listed in d&b NoizCalc technical white paper and in Bies, Hansen and Howard, Engineering Noise Control; turned into absorption with Delany and Bazley's model (1970).
• Trees: Li, Van Renterghem, Kang, Verheyen and Botteldooren, Sound absorption by tree bark, Applied Acoustics 165 (2020).
• Bounces and scattering: Vorländer and Embrechts (2004) on scattered reflections; ODEON's scattering coefficients (Zeng, Lynge and Rindel, 2006); Lambert's cosine law.
• Room size and reverb: Sabine's reverberation formula; the critical distance (Hopkins and Stryker, as given by Arup).
• Wind: Waddington and Lam's outdoor measurements of wind and sound; the US National Weather Service's blizzard definition to match the game's wind to real wind speeds.
• HRTF: Woodworth's formula for the delay between the ears.
• Under water: DOSITS (Discovery of Sound in the Sea), the air and water impedances.
• The sea as a line source: Hong Kong Environmental Protection Department, noise basics.

Disclaimer: development is AI assisted. Not fully human or AI. Donations: ko-fi.com/krosshair

0.5.2

• Fixed: walking up to a window with rain outside cut the rain in, and walking away cut it out again. The sound at each opening was tied to the opening's rank, so when a window became the bigger opening (or a new one turned up) its sound jumped across the room at full level. Each opening now keeps its own sound, a new one fades in where it is and a lost one fades out where it was. How closed in you are also glides over a second instead of stepping.

0.5.1

• Fixed: sound got through closed buildings. Pieces snapped together often leave a hairline gap between their colliders, and the one ray from you to a sound could run through it as if the wall were open. Every line is now three rays 8 cm apart, and what two of them agree on counts. The mod was at fault.
• Fixed: the room rays could take such a seam for a window or a door and route sounds through it. A gap counts as an opening only if the rays beside it get through too.
• Fixed: a wall right behind a sound (a torch, a chest or a workbench against the far side of a wall) didn't count: the mod ignored everything within 0.5 m of a sound so its own object wouldn't hide it. Now only the thing making the sound is left out. The mod was at fault.
• Fixed: a door's own sound could be hidden by the door: opening and closing were heard from the middle of the door's box, which for a door first seen open is out beside the doorway. They come from the hinge now, half way up. The mod was at fault.
• Fixed: a line through a busy build (walls, beams, poles, furniture) could have more hits than the mod recorded (8), and the wall could be among the ones dropped. It records 16 now, and a line with more than that counts as through a wall at least.

0.5.0

Indoors and outdoors

• Changed: the sea is shaded like the wind, as the whole shoreline it is: a wall or a house between you and it still shuts most of it out, but a single post or tree no longer can (it was one ray to one point). Heard from between the shore and the way that's open to it.
• Changed: the wind is shaped by what's round you. Behind a wall, a rock or a hill it drops to a low rumble (in their lee), it's heard from where it comes round and over what's upwind, and it comes in gusts and lulls instead of one even loop, more so the harder it blows.
• Changed: the outside heard from inside, rebuilt. Rain, wind, birds and the rest of the biome's sound play from your doors and windows (up to two), just outside each one and heard from there, as loud as the opening's share of the outside (about 10 dB under outside for a door, as measured homes with a window open). Through the walls only a quiet, dull bed gets in, and openings fade in and out instead of cutting. Before, it was one flat sound from nowhere: barely muffled, or nearly unmuffled the moment any opening was found.
• Changed: you can hear through walls. One wall counts once, however many pieces it's built from (a wall, a beam and a pole on one line were three walls), and the first wall takes 12 to 22 dB by how heavy it is, each after it 6 dB more and duller. With the measured losses stacked, a hearth in the next house was at -120 dB: silent, not muffled.
• Changed: muffling is steeper (12 dB an octave instead of 6), so a sound behind a wall is muffled, not just quieter.
• Fixed: sounds outside heard from inside rang through your room's reverb as bright as if they were in it: Unity's room reverb hears a sound before the mod muffles it. A sound now gets the room's reverb only as much as gets through to you, and sounds behind walls no longer get extra reverb.
• Fixed: stepping behind something (off a wall, with the sea behind it) shut a sound off for a moment before its way round was found, then opened it again. The way round is found first now.
• Fixed: the game's random calls (birds, gulls, insects) are placed at your own height, so in a basement or on a hillside they were in the ground, and one could land on your roof and sound like it was in the room. They sit in the open air above their spot, off buildings.
• Fixed: a door or window looking out at a hill or trees didn't count as an opening, and a seam in the roof could.
• Fixed: sounds already playing could be muffled by walls that weren't there: their checks read leftover hits from earlier ones (Unity only clears the first unused slot). The mod was at fault.
• Fixed: a sound behind a wall could seem to come from inside your room. Where you hear it from follows the precedence effect: the sound through the wall arrives first and sets the direction, and a window or corner only takes over when it's more than 10 dB louder.
• Improved: a sound coming through an opening bends round its nearest edge, not its middle, and loses nothing extra when the straight line passes through it (Kurze and Anderson, the lit side of an edge).

Reverb

• Changed: rooms sound like the real rooms they stand for. Valheim's buildings are about twice real size and bare, so they rang like halls; the reverb treats them as half the size and furnished, with the warmer tone from 0.1. Indoors it's cozier the more closed in you are: softer first reflections, a darker ring.
• Improved: stepping out of a space, its reverb dies away over that space's own reverb time (a cave's over seconds, a small room's at once).

Distance and loudness

• Changed: which way a sound is comes from the camera, as you see it; how far it is, what's in the way, which room you're in and whether you're under water come from your character's head again, where the game itself hears from (0.4.0 had moved all of it to the camera). Zooming out no longer makes your own steps quieter, and the camera slipping behind a wall no longer muffles the world.
• Changed: sounds reach further, just quieter. Past the game's own range for a sound it drops 6 dB more each time the distance doubles, instead of fading out to nothing.
• Changed: fires are as loud as how much is burning. The game plays a sconce's crackle as loud as a hearth's; now a sconce is about 14 dB quieter than a campfire.
• Fixed: quieter sounds far off cut out as you walked away (a mead ketill across the hall), and with more sounds than voices Unity cuts an old sound off or doesn't start a new one. Unity mixes only 32 sounds at once in Valheim and a busy base plays about 60: the mod asks for 128, so every sound plays to its end, and sounds too quiet to hear give way first if even that runs out.
• Changed: sounds upwind of you drop by at most 10 dB instead of the measured 20 and more, so a sound you can see doesn't all but vanish in a breeze. A choice for the game, not from a source.
• Removed: sounds arriving late with distance, and the Doppler shift.

Other

• Improved: a falling tree is heard from its trunk as it comes down, not from the stump.
• Fixed: a portal's hum dipped out for a moment as it was handed to the exit portal, which often doesn't count itself in use yet when you land. It's held on through the hand-over.
• Changed: pausing (the Esc menu) keeps the world sounding as it is, instead of switching to the menu's muffled mix.
• Fixed: switching the mod off left the reverb send it had set on sounds already playing; the game's own is put back.
• Improved: with Proximity Voice Chat, a voice comes from the speaker's head (it was 1.5 m above their feet, wrong when they crouch, sit or swim).
• Fixed: with your head under water, sounds under water with you were muffled as if they came through the surface.
• Fixed: on 5.1 and 7.1 speakers with the HRTF on, the centre and rear speakers went silent. The game's own panning is used there now.
• Fixed: a few material values didn't match the sources they're credited to: marble, ice, plank and heavy wood now absorb what the published tables say, and iron and ice walls follow the mass law as published.
• Removed, to keep the mod to what clearly matters: sounds reaching you by bouncing off walls (openings and corners cover it), and a creature's voice being duller from behind it.
• Performance: sounds too quiet to hear (under -60 dB where you are) aren't processed at all; every other sound gets the full HRTF. Distance, air and wind are worked out 4 times a second instead of every frame.
• README: every source links to where its numbers come from, and the values that don't come from a source are listed as such.

0.4.1

• Fixed: an endless loading screen with errors in the game's object clean-up (ZNetScene.RemoveObjects), since 0.3.0. The mod attached creature and weapon sounds to the creature so they'd move with it; in some setups those sounds are networked objects, and they were destroyed together with the creature while the game still tracked them. The mod was at fault. Networked sounds now follow their creature without being attached.
• Fixed: the Room reverb setting's description said the game's own reverb comes back outdoors. It doesn't: the mod's reverb is used everywhere and goes dry in the open.

0.4.0

• Changed: you now hear from the camera, not from your character. Left and right, near and far, and which room you're in follow your view.
• Fixed: a room's size counted the sky or the hills seen through its windows, doors and gaps, so rooms seemed several times bigger than they are.
• Improved: every sound gets the full HRTF. Before, only the nearest few did and the rest kept only a louder near ear, so you couldn't tell where a distant fight or animal was. The simpler version saved too little to be worth it.
• Removed: the echo off cliffs and big walls in the open. It was rarely heard and cost audio processing on every nearby sound while it was on. The room's reverb is unchanged.
• Improved: how much the air dulls distant sounds now follows the international standard for it (ISO 9613-1), with the weather: the game's warm, cold and freezing are matched to the real Norwegian weather they're modelled on (a Bergen summer day and night, the mountains in winter). Sounds 10 to 60 m away were too bright before.
• Improved: rocks, furniture and tree trunks between you and a sound now muffle it by their size: the sound goes over and round them, so a trunk barely matters and a boulder takes the highs off (the same barrier formula as corners and hills, over the top and round both sides). Before they all took off the same fixed amount.
• Improved: how much a room's reverb dulls over time and how bright its reflections are now come from what the room is made of, from published absorption figures per material (stone keeps the highs ringing, wood swallows the lows), plus the air.
• Improved: sound reaching you by bouncing off a wall is now as loud as the reflection would really be: what the surface doesn't absorb, mirrored where the angle is right and scattered evenly elsewhere, by how rough each material is.
• Removed: the forest's own reverb tail. Its values weren't backed by measurements.
• Changed: the ground, trees and iron now absorb each frequency band by published data. Ground uses the Nord2000 ground classes per biome (snow, moss, grass, forest floor, sand, packed ash), trees use measured bark, iron uses steel. Before, they had one rough value for every frequency.
• Improved: walls, floors, roofs and doors now block sound as much as real ones measure, by their material and thickness: a wood wall like a solid timber wall (about 29 dB of the lows, 37 dB at mid frequencies), a door like a solid wood door (less, as doors leak), stone like a brick wall (far more). Through a wall you hear a muffled but still recognisable sound, not just a rumble. Hills, rocks, trees and furniture are unchanged.
• Improved: indoors, the outside (rain, wind, birds) comes in through the openings and the open sky; what gets through closed walls is a faint low rumble. With the HRTF, it now comes fully from the openings' direction, not partly.
• Improved: sound bending round a corner or through a doorway loses what real sound does (the barrier formula used for noise walls, capped at 20 dB), more of its highs the longer the detour. Before it lost about 1 dB.
• Improved: wind. Downwind a sound carries a few dB further; upwind it can drop by up to 20 dB from about 100 m away, as measured outdoors (it was at most 4 dB). The game's wind is matched to real wind speeds by its snow storm being a blizzard.
• Improved: indoors, a random bird or insect call starts outside your walls instead of somewhere in your room, so it comes in through the windows and doors from their direction.
• Improved: a hill between you and a sound is now treated as what it is, a ridge the sound goes over: the higher it rises above the line between you, the more it takes off (the same barrier formula as corners).
• Improved: how much reverb a sound gets indoors now uses the standard critical distance (from the room's measured size and reverb time) instead of a fixed guess.
• Improved: under water. Sound crossing the surface keeps about 0.1% of its energy, as physics says (about 30 dB quieter), without the old muffling, which wasn't based on anything.
• Improved: the sea is a long shoreline, so it now fades 3 dB per doubling of distance like a real line of sound, not 6.
• Removed: the crackle fix from 0.2.7. Repairing the clicks in the game's sound files also took detail out of many deep sounds (footsteps, landings, climbing on stone), leaving them dull and distorted at random, depending on which variant of a sound played. A worse problem than the one it fixed, so the game's sound files are left as they ship again.
• Performance: the audio processing no longer times itself unless the debug log is on.

0.3.0

• Improved: sounds come from where they're made. The game often plays a sound at a character's feet or at the base of a piece:
  • Weapon swings and attacks come from the weapon and follow the swing. A bow's draw comes from the bow, the hammer's build sound from your hand.
  • Holstering comes from the slot on your back the item goes to, dropping from your hand, eating and drinking from your head, picking up from where the item was.
  • Creatures' growls, roars, calls and bites come from their head, their swings and claws from their weapon or arm, stomps and slams from their feet. A troll's roar and its club swing now come from two different places.
  • Chests sound from their lid, fires (sconces, hearths, braziers) from their flame, doors, smelters, fermenters and other pieces from their middle. Crafting sounds come from the crafting station instead of from you.
• Improved: anything that moves takes its sounds with it: reloading a crossbow or grappling hook, animals and pets, sounds on ships and carts.
• Improved: a ship's wake and water and other sounds outside the game's usual sound system now get the Doppler effect too.
• Removed: the "heard from its open part" backup from 0.2.7. It isn't needed now that sounds come from where they're made, and it made muffled chests sound like they were off to the right.
• Added: the wind in your ears. Outside, the wind is heard from the way it's blowing from: louder with an ear turned to it, quieter with your back to it. It fades out as you go indoors.
• Performance: fewer raycasts for sounds of pieces and creatures, and less work every frame for the Doppler effect.

0.2.7

• Fixed a vanilla bug: clicks and crackles in the game's sound effects, most obvious on wood and stone footsteps because they stand out against those deep sounds. This is in Valheim's own sound files, not something this mod caused. Two things are wrong with them: many clips have tiny bursts of noise baked in, and many were trimmed so they start in the middle of the sound instead of from silence, which clicks every time they play. I tried to fix both and hopefully fully succeeded. The mod repairs the sounds in memory as the game plays them; the game's files are not changed and no audio is added to the mod.
• Improved: if the spot a sound is made at is muffled but part of the thing making it is in the open (a chest set into a wall), it's heard from that open part, so something you can clearly see is heard clearly. Sounds that aren't muffled come from where they always did.

0.2.6

• Sorry, I put the wrong thing in the last changelog. Claude screwed me over: the crackles on wood/stone footsteps are a vanilla bug I'm trying to fix, but he put it in there like it's my damn fault. I shouldn't trust AI with changelogs. Sorry, fellas.
• No changes to the mod itself.

0.2.5

• Fixed: birds, seagulls and other outside sounds came through wooden walls too clearly. A wooden wall muffles as much as it did before 0.2.3 again; stone, marble and iron still muffle more than wood.
• Fixed: random biome sounds (birds, insects) and lava noises use the same game object, so lava could be treated as background ambience. They're now told apart where the game plays them: lava stays a real sound in the world, muffled by walls.
• Fixed: looping sounds the game itself doesn't keep updating were never rechecked for walls after they started. They're now rechecked like other sounds.
• Fixed: short random ambient sounds (an insect, a splash) could be cut off by the game's fade timer before their sound ended; they now play to their natural end.
• Fixed: a sound starting while the same source still played could restart or cut the old one, and a distance-delayed sound was started and then restarted. Delayed sounds now start once, and stale delayed stops are dropped.
• Fixed: possible crackle when a sound switched between full and light HRTF, and a rare case where an echo's memory was reused while still being played.
• Fixed: a sound made right next to you (opening a gate or door, chopping, mining) was attached to your character and turned with it, so it stayed on the same side as you turned. It now stays where it was made; only your own item sounds (equipping, eating, picking up, dropping) move with you.
• Fixed: random ambience indoors (a bird, an insect) kept the left/right it started with as you turned; it now stays in place.
• Debug log: more detail on wildlife sounds, footstep clips and audio-thread cost.

0.2.4

• Improved: entering and leaving caves, crypts and other enclosed spaces updates room reverb much faster, without lingering wet acoustics outside.
• Improved: exterior ambience switches promptly at room boundaries instead of waiting through Valheim's long sequential ambient-loop fades. Normal weather and biome fades keep their original timing.
• Fixed: distant sounds whose fade has already reached silence now stop immediately rather than repeatedly scheduling delayed stops; pending stop requests for the same source no longer accumulate.
• Known issues: occasional clicks on constructed wood/stone footsteps and abrupt endings of some swamp random ambient effects are still under investigation. The experimental footstep attack fade and ambient-clip pitch-timing workaround were removed because they did not resolve the reported problems.

0.2.3

• Optimized: HRTF priority follows estimated audibility rather than distance alone; callbacks for sounds already below -80 dB bypass expensive processing if no audible delayed echo remains. New debug counters break down full/light/plain DSP and silent buffers.
• Optimized: alternative paths are scheduled only for previously blocked sounds; room second-reflection jobs run on demand. The debug log now counts actual opening, corner, first- and second-reflection winners to judge whether added complexity pays off.
• Optimized: still rooms and coastlines reuse recent measurements with periodic refreshes; doors, pieces and new dungeon rooms invalidate the geometry measurements.
• Corrected: extended sounds now base future blocked-path decisions on their least-obstructed sampled point, not always the central ray.
• Added: timber, stone, marble and metal transmit different amounts of sound using the already known collider material; reflection candidates use absorption and angular plausibility in addition to path length. Corner candidates prefer physical blocker edges over fixed arbitrary offsets.
• Fixed: switching the mod off restores vanilla reverb zones instead of losing destroyed components, and reverts modified player and random-ambience AudioSource positioning and stereo panning. Conversion backups live on per-source filters so short-lived sounds don't accumulate stale tracking entries.
• Compatibility: dungeon audio setup uses the per-room placement method rather than the two DungeonGenerator methods whose postfixes Valheim AVX displaced.
• All existing acoustic features remain; the diagnostics help identify which processing and reflection paths are actually useful. Performance improvements vary by scene.
• Note: using Windows Sonic or Dolby Atmos spatial processing alongside the mod's own HRTF can reduce its positional clarity. For best results, disable Windows spatial processing while playing Valheim (manually; no system settings are changed by the mod).

0.2.2

• Fixed: birds and other random ambience could play inside your house, loud and unmuffled (the game places them at a random spot around you, often in your own room). Indoors they're heard through the walls and from the windows, like rain and wind.
• Fixed: rocky valleys and ravines barely echoed: their sides counted as being indoors. Echoes now fade only under a roof.

0.2.1

• Fixed: the mod reported its version as 0.1.2.
• README rewritten.

0.2.0

• Added: sound takes time to travel (343 m/s). A sound far away starts and stops as late as its distance makes it.
• Added: Doppler. Moving sounds shift in pitch as they come and go; our own, so the camera bumping about doesn't make sounds warble.
• Added: portals carry their hum. Going through, it isn't stopped and started again: it glides to where the exit portal will be, rides with you while you load and carries on as the exit portal's hum.
• Added: forests have their own soft reverb tail from the trunks round you.
• Added: the ground counts by what it is where each ray lands (snow, grass, forest floor, mud, sand, rock, paving, tilled soil), and the sea's surface reflects sound instead of rays passing through it to the sea bed.
• Changed: no reverb from the game is used anywhere now. Outdoors is measured like any room: open ground is dry, where the game added the same long reverb everywhere (open mountains sounded wetter than a forest).
• Changed: echo per sound, from each sound's own way there and back, instead of one delay for all; loops don't echo, and how hard the surface is decides how strong it is.
• Changed: quiet sounds fade out sooner than loud ones, by the game's own range for each.
• Changed: all your own movement and action sounds come from your character and move with it; a death wail follows the falling body; a creature's facing only shapes its calls.
• Changed: creatures' and players' shapes are their bodies (a player counted as 4 m wide before).
• Changed: levels of detail for the processing: every sound is processed, the nearest get the full HRTF, the rest a lighter direction, crossfaded when they switch.
• Added: HRTF strength setting.
• Fixed: stutter spikes of a few ms, several times a second. Switching a sound's filter on and off made Unity wait for its audio mixer; filters now stay on and simply pass sounds through when there's nothing to do.
• Fixed: birds, gusts and other random ambience were far too quiet with Realistic distance (up to 20 dB); they keep the game's own fade.
• Fixed: a tick at the start of some sounds (old audio left in the delay line).
• Fixed: errors from creatures without a head point (fish, birds) stopped some sounds being checked.

0.1.3

• Fixed: stutter, distorted sound and hitches where a lot plays at once (a swamp in the rain), worst on slower machines. Only the nearest playing sounds are processed now, up to a count that follows how busy the audio thread really is (measured, lowered at once when it's busy); the rest are left to the game's own panning. Sounds that don't need processing no longer cost anything, and the per-sound work is faster.
• Fixed: forests and swamps sounded like a cave. Trees counted as walls: a dense swamp measured as an enclosed room (long reverb, muffled rain), every trunk muffled sounds and echoed them. Trees now scatter sound instead: they barely enclose you, muffle little and never echo.

0.1.2

• Added: sound reaching you by bouncing. Room rays bounce a second time off what they hit (angle in = angle out), and sounds behind walls also try the shortest bounce paths: down a corridor and round its far corner, round two corners.
• Added: echo. Out in the open, a big hard surface facing you 15 to 50 m away (a cliff, a hillside, a wall) sends sounds back from its direction, delayed by its real distance.
• Added: rain and wind indoors come from the opening's real direction with the HRTF on (behind and above as well as left and right), keeping their stereo.
• Added: the air dulls distant sounds' highs (a fight 60 m away is duller, not just quieter).
• Changed: no more pitch drop for distant sounds in the Mistlands mist (fog doesn't change pitch); they keep their reverb there too.
• Added: Wire's Stackify support. Its chest sounds after a quick stack or restock come from each chest, as world sounds.
• Changed: sounds that used to cut off at their max distance now reach twice as far and fade out there, instead of fading inside their range (a hit 30 m away is heard again).
• Optimized: the list of sounds tracked for direction and distance changes in place instead of being rebuilt; locations and dungeons get their sound filters and lose their reverb zones as they're placed, instead of scene-wide searches every few seconds.
• Changed: the HRTF's outer-ear dip is narrower and only for sounds well above or below you, so equipment and other sounds near your character aren't dulled.

0.1.0

• First upload: ray traced room reverb, muffling through walls, paths through openings and round corners, ambience and under-water muffling, the sea heard from the sea, HRTF, sounds following their source, your own sounds from your character, distance fade, Proximity Voice Chat support.