Adaptive Music

Deep reference for designing and implementing music systems that respond to gameplay in real time - covering horizontal re-sequencing, vertical layering, transition design, and implementation in FMOD Studio and Wwise.

---

Adaptive music techniques

Vertical layering (additive)

All layers play simultaneously, synchronized to the same tempo. Individual layers fade in/out based on game parameters.

Layer structure example (combat music):

Layer 1: Ambient pad          [always on, volume 0.7]
Layer 2: Rhythmic pulse       [on when tension > 0.2]
Layer 3: Percussion           [on when tension > 0.4]
Layer 4: Bass + drums         [on when tension > 0.6]
Layer 5: Full brass/strings   [on when tension > 0.8]
Layer 6: Choir + cymbals      [on at tension = 1.0]

Implementation rules:

• All layers must share the same BPM, key, and time signature
• Compose so any combination of active layers sounds good
• Fade transitions: 0.5-2.0 seconds depending on tempo
• Use RTPC or parameter to drive layer volumes (not on/off switching)

Horizontal re-sequencing

Music is divided into segments (bars or phrases) that can be rearranged in real time. The system picks the next segment based on game state.

Segment pool:
  [Intro] -> [Explore_A] -> [Explore_B] -> [Explore_C]
                                              |
                                        [Transition_ToCombat]
                                              |
                            [Combat_A] -> [Combat_B] -> [Combat_Loop]
                                              |
                                        [Transition_ToExplore]
                                              |
                                        [Explore_A] (loop back)

Rules:

• Segments must start and end on musically compatible boundaries (bar lines)
• Transitions between segments happen at defined sync points (next bar, next beat)
• Each segment should be self-contained enough to loop if the state doesn't change

Stingers and transition segments

Short musical phrases (1-4 bars) that play during state changes to smooth transitions:

Stinger type	Duration	Trigger
Discovery	2-4 bars	Finding an item, entering new area
Danger	1-2 bars	Enemy spotted, trap triggered
Victory	4-8 bars	Boss defeated, level complete
Death	2-4 bars	Player dies
Transition bridge	2-4 bars	Between musical states (explore -> combat)

Stingers typically override or layer on top of the current music, then fade back to the new state's music.

Branching

Pre-authored alternate paths at decision points. Most common in narrative games:

                    [Verse 1]
                    /        \
           [Happy Chorus]  [Dark Chorus]
                    \        /
                    [Verse 2]

The branch is selected by a game parameter or state at the decision point. Less flexible than layering but allows for more compositionally complex transitions.

---

Music state machine design

Most games use a state machine to drive adaptive music:

Example: action-adventure game

States:
  MENU        -> ambient pad, no gameplay music
  EXPLORE     -> exploration theme, low intensity
  ALERT       -> tense variation, percussion enters
  COMBAT      -> full combat music, all layers
  BOSS        -> unique boss theme
  VICTORY     -> victory stinger, fade to explore
  DEATH       -> death stinger, silence, respawn into explore
  CUTSCENE    -> scripted music, external control

Transitions:
  EXPLORE -> ALERT:   Fade over 2 bars, add percussion layer
  ALERT -> COMBAT:    Stinger + cut to combat at next bar
  COMBAT -> EXPLORE:  Combat winds down over 4 bars, stinger, crossfade
  COMBAT -> BOSS:     Immediate transition with boss intro stinger
  BOSS -> VICTORY:    Victory stinger overlays, fade boss music
  * -> CUTSCENE:      Duck gameplay music, crossfade to cutscene track
  CUTSCENE -> *:      Crossfade back to appropriate state music

Cooldown and hysteresis

Prevent rapid music flickering when game state oscillates:

• Cooldown timer: After entering a state, stay for minimum 4-8 seconds before allowing transition to a lower-intensity state
• Hysteresis: Use different thresholds for entering vs leaving a state. Example: enter COMBAT at threat > 0.7, leave COMBAT at threat < 0.3
• Transition queue: If a transition is requested while another is in progress, queue it. Don't interrupt transitions.

---

Implementation in FMOD Studio

Vertical layering setup

1. Create a Music Event
2. Add multiple Audio Tracks (one per layer)
3. Place audio on each track, all synchronized to the same timeline
4. Create a local parameter (e.g., "Intensity", 0.0 to 1.0)
5. Add volume automation on each track driven by the parameter:
   • Track 1 (pad): constant volume
   • Track 2 (perc): automate from silent to full between 0.2-0.3
   • Track 3 (bass): automate between 0.4-0.5
   • (continue for each layer)
6. Set the event to loop (add a loop region on the timeline)

Horizontal re-sequencing setup

1. Create a Music Event
2. Add a Logic Track with transition markers
3. Use Transition Regions and Destinations:
   • Add named destination markers at each segment start
   • Create transition conditions tied to parameters
4. Alternative: use the Multi Instrument + parameter-driven playlist

Stinger implementation

1. Create a separate one-shot event for each stinger
2. Use FMOD's callback system to time the stinger to the next beat/bar:

// Quantize stinger to next beat
musicInstance.getTimelinePosition(out int position);
int beatLength = 60000 / bpm; // ms per beat
int nextBeat = ((position / beatLength) + 1) * beatLength;
int delay = nextBeat - position;

// Schedule stinger
StartCoroutine(PlayStingerAfterDelay("event:/Music/Stinger_Combat", delay));

---

Implementation in Wwise

Music Switch Container

1. Create a Music Switch Container
2. Associate it with a State Group (e.g., MusicState: Explore, Combat, Boss)
3. Add child Music Playlist Containers - one per state
4. Each playlist contains Music Segments and defines playback order
5. Open the Transition Editor to define rules between states

Transition rules in Wwise

In the Music Switch Container's Transition Editor:

From	To	Rule
Explore	Combat	Exit at next bar, play transition segment, enter at start
Combat	Explore	Exit at next bar, 2-bar fade out, enter at start
Any	Boss	Exit immediate, play boss intro stinger, enter at start
Boss	Victory	Exit at next bar, play victory stinger

Vertical layering in Wwise

1. Create a Music Segment with multiple tracks
2. Each track represents a layer
3. Use RTPC to control each track's volume
4. Or use States with volume overrides per track:
   • Low intensity state: tracks 1-2 at 0 dB, tracks 3-5 at -96 dB
   • High intensity state: all tracks at 0 dB
   • Define transition time between states (1-2 seconds)

---

Composition guidelines for adaptive music

General rules

• Compose in layers from the start - Don't write a finished piece and try to split it later. Each layer must function independently.
• Avoid strong melodic hooks in optional layers - If a melody might not play, don't make it the centerpiece. Put catchy melodies in the always-on base layer.
• Match energy levels to game states - Map your musical intensity scale (1-10) to your game's intensity scale.
• Key and tempo consistency - All layers and segments in a music system should share the same key (or compatible keys) and tempo.

Tempo and sync

• Lock all layers to the same BPM grid
• Typical tempos: exploration 80-100 BPM, combat 120-160 BPM
• If switching between tempos, use transition segments that ritardando/accelerando
• Quantize all transitions to bar boundaries (not beat) for smoother results

Loop points

• Music segments should loop seamlessly - match the waveform at loop boundaries
• Place loop points at bar lines, never mid-beat
• Test loops by listening for 5+ repetitions - subtle clicks or rhythmic bumps become obvious after several repeats
• Export loops with a brief tail (100-200ms) for crossfade if needed

---

Testing adaptive music

Manual testing checklist

• Each music state sounds good on its own (no missing layers)
• Transitions between adjacent states are smooth
• Transitions between non-adjacent states work (e.g., straight from EXPLORE to BOSS)
• Rapid state changes don't cause audio glitches or overlapping music
• Hysteresis/cooldown prevents flickering at state boundaries
• Stingers align to the beat grid
• Music loops are seamless after 5+ repetitions
• Volume levels are consistent across all states (no sudden jumps)

Profiler monitoring

In FMOD Studio or Wwise Profiler:

• Monitor voice count during music playback (should stay under budget)
• Check CPU usage of music events (streaming vs memory)
• Verify transitions fire at expected sync points
• Inspect parameter values match expected game state

---

Common pitfalls

Mistake	Impact	Fix
Layers not synchronized	Music sounds out of time	Ensure all layers share the same BPM and start point
No transition segments	Jarring cuts between states	Compose 2-4 bar bridge segments for major transitions
Music reacts too fast	Flickering between states feels chaotic	Add hysteresis and cooldown timers
All layers always audible	No dynamic range; combat doesn't feel different from exploration	Reserve 40-60% of layers for high-intensity states only
Hard volume cuts	Audible pops and clicks	Always fade over 0.5-2 seconds; never set volume to 0 instantly
Ignoring memory for music	Music streams compete with SFX for bandwidth	Stream music from disk; limit to 2-3 simultaneous music streams

FMOD Studio Guide

Comprehensive reference for FMOD Studio integration in game projects, covering project setup, event authoring, parameter automation, and runtime C# API usage.

---

Installation and setup

Unity integration

1. Download the FMOD for Unity plugin from fmod.com/unity
2. Import the .unitypackage into your Unity project
3. Go to FMOD > Edit Settings and set the Studio Project Path to your .fsproj file
4. Set the Build path to Assets/StreamingAssets (default)
5. Build banks in FMOD Studio (File > Build) before running in Unity

Unreal Engine integration

1. Download the FMOD for Unreal plugin
2. Extract to <Project>/Plugins/FMODStudio/
3. In Project Settings > FMOD Studio, set the Studio Project Directory
4. Banks are built and loaded automatically with the plugin

Bank management

Banks are the compiled audio containers that ship with your game:

• Master Bank - Always loaded; contains buses, VCAs, and global events
• Master Bank.strings - Contains event name-to-GUID mappings; required for path lookups
• Level/scene banks - Load per scene to manage memory
• Dialogue banks - Separate for localization

// Loading a bank at runtime
FMODUnity.RuntimeManager.LoadBank("Level_Forest", true);

// Unloading when leaving the scene
FMODUnity.RuntimeManager.UnloadBank("Level_Forest");

---

Event authoring in FMOD Studio

Event types

Type	Use case
2D Event	UI sounds, music, narrator voice
3D Event	In-world sounds that need spatialization
Spatializer (panner)	Controls how 3D events are placed in the stereo/surround field
Timeline	Sound placed on a timeline with automation lanes
Action Sheet	Logic-based sound design using parameters and conditions

Creating a basic SFX event

1. Right-click Events folder > New Event
2. Drag audio files onto the timeline
3. Set the event to 3D if it needs spatialization (Properties > Spatializer)
4. Configure attenuation: set min/max distance in the 3D panner
5. Assign to a bus (e.g., SFX/Player)

Parameter types

Parameter	Scope	Example
Event parameter (local)	Per-instance	"Speed" on a car engine event
Global parameter	Shared across all events	"TimeOfDay", "ThreatLevel"
Built-in: Distance	Automatic	Based on listener-to-source distance
Built-in: Direction	Automatic	Angle to source relative to listener

Multi Instrument (randomization)

For sound variation:

1. Add a Multi Instrument to the event timeline
2. Drag 3-5 variants into the playlist
3. Set Playlist Mode: Shuffle (avoids repeats)
4. Set Trigger Behavior: Sequential or Steal Oldest
5. Add pitch randomization: right-click timeline > Add Modulation > Pitch (-200 to +200 cents)
6. Add volume randomization: similar, -1 to +1 dB

---

C# Runtime API

Core patterns

// One-shot: fire and forget (short SFX)
FMODUnity.RuntimeManager.PlayOneShot("event:/SFX/Explosion", transform.position);

// Persistent instance: looping sounds, music, or anything needing control
FMOD.Studio.EventInstance engineSound;

void Start()
{
    engineSound = FMODUnity.RuntimeManager.CreateInstance("event:/SFX/Engine");
    engineSound.start();
}

void Update()
{
    // Update 3D position
    engineSound.set3DAttributes(FMODUnity.RuntimeUtils.To3DAttributes(transform));

    // Update parameter
    engineSound.setParameterByName("RPM", currentRPM);
}

void OnDestroy()
{
    engineSound.stop(FMOD.Studio.STOP_MODE.ALLOWFADEOUT);
    engineSound.release();
}

Parameter control

// Local parameter (on a specific event instance)
instance.setParameterByName("Health", playerHealth);

// Global parameter (affects all events listening to it)
FMODUnity.RuntimeManager.StudioSystem.setParameterByName("TimeOfDay", 0.75f);

// Get current value
instance.getParameterByName("Speed", out float value);

Bus and VCA control

// Get a bus reference
FMOD.Studio.Bus musicBus = FMODUnity.RuntimeManager.GetBus("bus:/Music");

// Set volume (0.0 to 1.0, linear scale)
musicBus.setVolume(0.5f);

// Mute/unmute
musicBus.setMute(true);

// Pause all sounds on a bus
musicBus.setPaused(true);

// VCA (Volume Control Automation) for player-facing sliders
FMOD.Studio.VCA masterVCA = FMODUnity.RuntimeManager.GetVCA("vca:/Master");
masterVCA.setVolume(settingsSliderValue);

Snapshots

Snapshots are mix presets that blend in/out at runtime:

// Activate a snapshot (e.g., underwater muffling)
FMOD.Studio.EventInstance underwaterSnapshot;

void EnterWater()
{
    underwaterSnapshot = FMODUnity.RuntimeManager.CreateInstance("snapshot:/Underwater");
    underwaterSnapshot.start();
}

void ExitWater()
{
    underwaterSnapshot.stop(FMOD.Studio.STOP_MODE.ALLOWFADEOUT);
    underwaterSnapshot.release();
}

Callback system

// Listen for timeline markers (e.g., beat markers in music)
instance.setCallback(MusicCallback,
    FMOD.Studio.EVENT_CALLBACK_TYPE.TIMELINE_MARKER |
    FMOD.Studio.EVENT_CALLBACK_TYPE.TIMELINE_BEAT);

[AOT.MonoPInvokeCallback(typeof(FMOD.Studio.EVENT_CALLBACK))]
static FMOD.RESULT MusicCallback(
    FMOD.Studio.EVENT_CALLBACK_TYPE type,
    IntPtr instancePtr,
    IntPtr parameterPtr)
{
    if (type == FMOD.Studio.EVENT_CALLBACK_TYPE.TIMELINE_MARKER)
    {
        var marker = (FMOD.Studio.TIMELINE_MARKER_PROPERTIES)
            Marshal.PtrToStructure(parameterPtr,
                typeof(FMOD.Studio.TIMELINE_MARKER_PROPERTIES));
        Debug.Log($"Marker: {marker.name} at {marker.position}ms");
    }
    return FMOD.RESULT.OK;
}

---

Common pitfalls

Issue	Cause	Fix
No sound plays	Bank not loaded or event path typo	Check bank loading; verify path matches FMOD Studio
Sound plays but no 3D	Event not set to 3D, or 3D attributes not updated	Enable spatializer on event; call set3DAttributes every frame
Memory spike on scene load	Loading all banks at once	Use per-scene banks; load async
Sound continues after scene change	Instance not stopped/released	Always stop + release in OnDestroy
Clicking/popping on stop	Abrupt stop without fade	Use STOP_MODE.ALLOWFADEOUT; add AHDSR on event
GC allocation every frame	Creating strings for parameter names	Cache event paths and parameter IDs; use setParameterByID

---

Project organization best practices

FMOD Studio Project/
  Events/
    Music/
      Combat.fspro
      Exploration.fspro
    SFX/
      Player/
        Footstep.fspro
        Jump.fspro
      Weapons/
        Pistol_Fire.fspro
      Environment/
        Wind.fspro
    UI/
      Button_Click.fspro
    Voice/
      Narrator/
  Snapshots/
    Underwater
    PauseMenu
  Buses/
    Music
    SFX
    UI
    Voice

Name events with a clear hierarchy: event:/SFX/Player/Footstep. This maps directly to the folder structure and makes code references self-documenting.

Spatial Audio

Deep reference for 3D audio systems in games - covering spatialization techniques, HRTF rendering, distance attenuation, occlusion/obstruction, reverb zones, and platform-specific considerations.

---

Spatialization techniques

Channel-based panning

The simplest approach: pan a mono source across a speaker layout (stereo, 5.1, 7.1).

• Stereo: left-right panning based on source angle relative to listener
• Surround (5.1/7.1): VBAP (Vector Base Amplitude Panning) distributes sound across the nearest speaker pair
• Pros: Low CPU cost, compatible with all hardware
• Cons: Limited elevation perception, sweet-spot dependent

HRTF (Head-Related Transfer Function)

HRTF simulates how sounds reach each ear differently based on direction, using impulse responses measured from human heads:

• Provides full 3D perception including elevation (above/below)
• Essential for headphone users and VR/AR
• CPU cost per source: moderate (convolution with HRTF filters)

How HRTF works:

1. Determine azimuth and elevation angle from listener to source
2. Look up the corresponding HRTF pair (left ear, right ear) from a database
3. Convolve the mono source with each ear's impulse response
4. Output binaural stereo signal

HRTF databases:

• SOFA format - Standard for HRTF data interchange
• Resonance Audio (Google) - Built-in HRTF, free, Ambisonics-based
• Steam Audio (Valve) - Physics-based propagation + HRTF
• Oculus Audio SDK - Optimized for Meta Quest, personalized HRTF

Ambisonics

Ambisonics encodes a full spherical sound field independently of speaker layout:

• First-order (4 channels): Adequate for ambient beds, skyboxes
• Third-order (16 channels): Better localization, good for spatial music
• Decoded to any output format (stereo, surround, binaural) at the listener

Use case: encode complex ambient environments (forest, city) as an Ambisonic bed, then decode to the player's output format. Individual point sources (gunshots, footsteps) should use direct HRTF or panning, not Ambisonics.

---

Distance attenuation

Distance attenuation controls how volume decreases as the listener moves away from a source. Common curves:

Curve	Formula	Use case
Linear	1 - (d / maxDist)	Simple, predictable, good for small scenes
Logarithmic (inverse)	1 / (1 + k * d)	Realistic for outdoor environments
Inverse square	1 / (1 + k * d^2)	Physically accurate (real-world sound)
Custom (spline)	Artist-defined curve	Most control, used in AAA productions

Attenuation parameters

• Min distance: Below this distance, volume is at maximum (no attenuation)
• Max distance: Beyond this, volume is zero (or at the curve's minimum)
• Rolloff factor: Steepness of the curve between min and max

Typical values:

• Footsteps: min 1m, max 15m
• Gunshots: min 3m, max 100m
• Ambient loops: min 5m, max 50m
• Music: no attenuation (2D)

---

Occlusion and obstruction

Definitions

• Occlusion: Source is fully behind geometry (no direct or reflected path). Apply both low-pass filter AND volume reduction.
• Obstruction: Geometry blocks direct path but reflected paths exist (e.g., sound goes around a corner). Apply low-pass filter only; volume stays similar.

Implementation approaches

Raycast-based (common, CPU-friendly):

1. Cast a ray from listener to source each frame
2. Count geometry hits along the path
3. Map hit count to an occlusion value (0.0 = clear, 1.0 = fully occluded)
4. Send occlusion value to audio middleware as a parameter
5. Middleware applies low-pass filter + volume curve based on value

// Unity example
void UpdateOcclusion(Transform source, Transform listener)
{
    Vector3 direction = source.position - listener.position;
    float distance = direction.magnitude;
    int hits = Physics.RaycastNonAlloc(
        listener.position, direction.normalized,
        raycastBuffer, distance, occlusionLayerMask);

    float occlusion = Mathf.Clamp01(hits * 0.25f);

    // Send to FMOD
    eventInstance.setParameterByName("Occlusion", occlusion);

    // OR send to Wwise
    AkSoundEngine.SetObjectObstructionAndOcclusion(
        gameObject, AkSoundEngine.AK_INVALID_GAME_OBJECT,
        occlusion, 0f);
}

Multi-ray (more accurate):

• Cast 5-7 rays in a cone pattern from listener toward source
• Average the results for smoother occlusion transitions
• More CPU expensive but avoids binary pop between occluded/unoccluded

Physics-based propagation (Steam Audio, Wwise Spatial Audio):

• Full sound propagation simulation through geometry
• Handles diffraction (sound bending around edges), transmission through walls, and multi-path reflections
• Most realistic but highest CPU cost
• Best for VR or premium AAA titles

---

Reverb zones

Reverb simulates how sound bounces within an enclosed space. In games, reverb is applied per-zone:

Zone setup pattern

1. Define zones as trigger volumes (box, sphere, or mesh collider)
2. Each zone has a reverb preset: room size, decay time, wet/dry mix
3. When the listener enters a zone, blend to that zone's reverb
4. Use auxiliary sends in FMOD/Wwise to route audio through reverb buses

Common reverb presets

Environment	Decay time	Pre-delay	Wet level	Character
Small room	0.4-0.8s	5ms	-10 dB	Tight, intimate
Large hall	1.5-3.0s	20ms	-6 dB	Spacious, cathedral
Cave	2.0-4.0s	30ms	-3 dB	Dark, echoing
Outdoor open	0.1-0.3s	0ms	-20 dB	Dry, minimal
Bathroom/tile	0.8-1.5s	5ms	-4 dB	Bright, reflective
Sewer/tunnel	1.5-2.5s	15ms	-5 dB	Metallic, resonant

Blending between zones

When transitioning between zones (e.g., walking from a cave into open air):

• Cross-fade between reverb sends over 0.5-1.0 seconds
• Use portal-based blending if available (Wwise Spatial Audio rooms/portals)
• Never hard-cut between reverb presets - it sounds unnatural

---

Platform considerations

Platform	Output	Recommended approach
PC (speakers)	Stereo/5.1/7.1	Channel-based panning; HRTF optional for headphones
PC (headphones)	Binaural stereo	HRTF-based spatialization
Console (TV)	5.1/7.1 Atmos	Channel-based or Dolby Atmos object audio
VR (Quest, PCVR)	Binaural stereo	HRTF mandatory; head tracking updates listener orientation
Mobile	Stereo (speakers/buds)	Simple panning; HRTF for earbuds if CPU allows

VR-specific considerations

• Update listener position AND orientation every frame from the HMD
• Use room-scale HRTF (accounts for near-field sources < 1m)
• Haptic feedback for bass frequencies (controller rumble) enhances immersion
• Budget: 20-30 spatialized sources max on mobile VR (Quest)

Performance budgets

Platform	Max simultaneous voices	HRTF sources	Budget
PC	64-128	32-64	3-5% CPU
Console	48-96	24-48	2-4% CPU
Mobile VR	24-48	12-24	4-6% CPU
Mobile phone	16-32	8-16	2-3% CPU

---

Troubleshooting spatial audio

Symptom	Likely cause	Fix
Sound doesn't move when turning	Listener orientation not updating	Update listener rotation every frame
Sound is always centered	Source and listener at same position	Ensure 3D attributes are set from actual world positions
Sound pops when crossing zone boundary	Hard reverb switch	Implement crossfade between reverb zones
HRTF sounds "inside head"	Source too close; no externalization	Add slight reverb or early reflections to externalize
Elevation not perceived	Using panning instead of HRTF	Switch to HRTF-based spatialization for headphone users
Occlusion pops on/off	Single raycast binary result	Use multi-ray averaging or interpolate occlusion value over time

Wwise Guide

Comprehensive reference for Audiokinetic Wwise integration in game projects, covering project structure, SoundBank workflow, RTPC, states, switches, and engine integration.

---

Installation and setup

Unity integration

1. Install the Wwise Unity Integration from the Audiokinetic Launcher
2. The launcher installs the plugin and creates a WwiseProject folder
3. In Unity: Wwise > Wwise Settings, configure platform targets
4. Generate SoundBanks from the Wwise Authoring Tool before running
5. SoundBanks are placed in Assets/StreamingAssets/Audio/GeneratedSoundBanks/

Unreal Engine integration

1. Wwise has a built-in Unreal integration - install via Audiokinetic Launcher
2. Set the Wwise Project path in Project Settings > Wwise
3. Use AkComponent and AkAmbientSound actors for 3D sources
4. SoundBanks auto-generate during build (or manually via Wwise Picker)

---

Core Wwise concepts

Object hierarchy

Project
  |- Actor-Mixer Hierarchy    (sound design: SFX, Foley, ambience)
  |    |- Work Units
  |         |- Actor-Mixers   (logical grouping)
  |              |- Random Containers
  |              |- Sequence Containers
  |              |- Switch Containers
  |              |- Blend Containers
  |              |- Sounds
  |- Interactive Music Hierarchy  (adaptive music)
  |    |- Music Switch Containers
  |    |- Music Playlist Containers
  |    |- Music Segments
  |- Events                   (triggers fired from code)
  |- Game Syncs               (RTPCs, states, switches, triggers)
  |- SoundBanks               (compiled output for runtime)
  |- Busses                   (mixing hierarchy)

Container types

Container	Purpose	Example
Random	Play a random child each trigger	Footstep variations
Sequence	Play children in order	Dialogue lines, reload sequence
Switch	Select child based on a game switch	Surface material for footsteps
Blend	Crossfade between children based on RTPC	Wind intensity (calm to storm)
Music Switch	Transition between music states	Combat vs exploration music
Music Playlist	Sequence music segments with transitions	Level soundtrack

Events

Events are the bridge between game code and audio content. An event contains one or more actions:

Action	Description
Play	Start playing a sound object
Stop	Stop a playing sound
Pause / Resume	Pause/resume playback
Set Switch	Change a switch value
Set State	Change a state value
Set Game Parameter	Change an RTPC value

---

Game Syncs

RTPC (Real-Time Parameter Control)

RTPCs are continuous parameters that modulate sound properties in real time.

Common RTPCs:
  - Health (0-100) -> drives music intensity, heartbeat volume
  - Speed (0-300) -> drives engine pitch, wind volume
  - Distance (auto) -> built-in distance attenuation
  - TimeOfDay (0-24) -> ambient sound blend

Map RTPC values to properties:

1. In the sound's Property Editor, right-click a property (Volume, Pitch, LPF)
2. Add RTPC binding
3. Draw a curve mapping RTPC input range to property output range

States

States are discrete, game-wide modes. Only one state per state group is active.

State Groups:
  - PlayerState: Alive, Dead, Spectating
  - Location: Indoor, Outdoor, Underwater, Cave
  - GamePhase: Menu, Gameplay, Cutscene, Paused

When a state changes, all sounds with state-based property overrides transition smoothly (configurable transition time per state group).

Switches

Switches are per-object selectors (unlike states which are global).

Switch Groups:
  - Surface: Concrete, Wood, Metal, Grass, Water
  - WeaponType: Pistol, Rifle, Shotgun, Melee
  - EnemyType: Zombie, Robot, Human

Switch Containers select which child to play based on the current switch value.

---

SoundBank workflow

SoundBanks are the compiled audio packages loaded at runtime.

Bank organization strategy

Bank	Contents	Load timing
Init.bnk	Engine initialization data	Game startup (always first)
Common.bnk	UI sounds, player sounds, global events	Game startup
Music_Exploration.bnk	Exploration music	When entering exploration
Music_Combat.bnk	Combat music	When combat begins or level loads
Level_Forest.bnk	Forest-specific ambience and SFX	Scene load
VO_English.bnk	English voice-over	Based on language setting

Code integration

// Unity + Wwise example

// Post an event (fire and forget)
AkSoundEngine.PostEvent("Play_Footstep", gameObject);

// Post an event with callback
AkSoundEngine.PostEvent("Play_Dialogue", gameObject,
    (uint)AkCallbackType.AK_EndOfEvent, DialogueEndCallback, null);

// Set RTPC value
AkSoundEngine.SetRTPCValue("Health", playerHealth, gameObject);

// Set global RTPC
AkSoundEngine.SetRTPCValue("TimeOfDay", currentHour);

// Set Switch (per game object)
AkSoundEngine.SetSwitch("Surface", "Wood", gameObject);

// Set State (global)
AkSoundEngine.SetState("Location", "Underwater");

// Load/unload banks
AkBankManager.LoadBank("Level_Forest");
AkBankManager.UnloadBank("Level_Forest");

Unreal integration

// Post event
UAkGameplayStatics::PostEvent(FootstepEvent, this, 0, FOnAkPostEventCallback());

// Set RTPC
UAkGameplayStatics::SetRTPCValue(nullptr, Health, 0, this, FString("Health"));

// Set Switch
UAkGameplayStatics::SetSwitch(SurfaceSwitchGroup, SurfaceSwitchValue, this);

// Set State
UAkGameplayStatics::SetState(LocationStateGroup, UnderwaterState);

---

Adaptive music in Wwise

Music Switch Container setup

1. Create a Music Switch Container
2. Assign a State Group or Switch Group (e.g., CombatState: Peaceful, Alert, Combat)
3. Add Music Playlist Containers as children - one per state
4. Each playlist contains Music Segments (the actual music chunks)
5. Define Transition Rules between states:
   • Transition at next bar, next beat, next marker, or immediate
   • Optional transition segment (stinger/bridge)
   • Fade-in/fade-out curves

Transition matrix

              -> Peaceful  -> Alert    -> Combat
Peaceful:       N/A          Next Bar   Next Beat + Stinger
Alert:          Next Bar     N/A        Next Beat
Combat:         Next Bar     Next Bar   N/A

Vertical layering in Wwise

1. Create a Music Segment with multiple tracks (layers)
2. Use States or RTPCs to control each track's volume
3. Example: drums layer fades in as RTPC "Intensity" rises above 0.5
4. All layers share the same tempo/time signature and stay synchronized

---

Spatial audio in Wwise

Wwise Spatial Audio provides built-in room/portal simulation:

Rooms and portals

Setup:
1. Define AkRoom volumes in your scene (box or mesh colliders)
2. Place AkPortal at doorways between rooms
3. Each room references a reverb aux bus
4. Wwise automatically routes audio through portals
   - Sound in adjacent room: audible through portal, with diffraction
   - Sound in distant room: attenuated based on portal chain

Reflect plugin

For real-time early reflections:

1. Enable Wwise Reflect on emitters that need reflections
2. Define geometry (walls, floors) using AkGeometry components
3. Reflect calculates early reflections based on actual scene geometry
4. CPU cost scales with geometry complexity - use simplified collision mesh

---

Common pitfalls

Issue	Cause	Fix
Init.bnk not found	Bank path misconfigured or not generated	Regenerate banks; verify StreamingAssets path
Event not found	Event not included in any SoundBank	Check SoundBank contents in Wwise; add event to bank
Sound plays from wrong position	Missing or stale AkGameObjectID	Ensure gameObject passed to PostEvent is correct
Memory overflow	Too many banks loaded simultaneously	Use per-scene bank loading; monitor with Wwise Profiler
Music transition sounds wrong	Transition rule misconfigured	Use Wwise Profiler to inspect transition; check rules
Switch not working	Switch set on wrong game object	Switches are per-object; verify the correct GameObject