absolutelyskilled/game-audio

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Game Audio

Game audio encompasses every sound a player hears - from UI clicks to orchestral scores that shift with gameplay. Unlike film audio, game audio is non-linear and reactive: sounds must respond to player actions, environmental state, and game events in real time. This skill covers sound design fundamentals, adaptive music composition and implementation, spatial (3D) audio systems, and professional middleware tools (FMOD Studio and Audiokinetic Wwise) that power audio in most shipped titles.

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When to use this skill

Trigger this skill when the user:

• Needs to design or implement a sound effects system for a game
• Wants to create adaptive or dynamic music that responds to gameplay
• Is setting up spatial/3D audio with HRTF or attenuation curves
• Needs to integrate FMOD Studio or Wwise into a game engine
• Wants to architect a sound event system or audio manager
• Asks about audio mixing, buses, ducking, or signal routing
• Needs to optimize audio for memory, CPU, or streaming performance
• Wants to build dynamic soundscapes or ambient audio layers

Do NOT trigger this skill for:

• Music composition theory or notation (use a music theory skill)
• Non-game audio production like podcast editing or mastering (use audio-production)

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Key principles

1. Audio is reactive, not scripted - Game audio cannot be authored linearly like film. Every sound must be designed as a response to an event. Think in terms of event-to-sound mappings, not timelines.

2. Less is more in the mix - Players process audio subconsciously. A clean mix with 4-6 prominent sounds is more impactful than 20 competing layers. Use priority systems, ducking, and voice limits to keep the mix focused.

3. Variation prevents fatigue - Any sound heard more than twice needs randomization. Use round-robin containers, pitch/volume randomization, and multiple samples to prevent repetition fatigue.

4. Spatial audio sells immersion - Proper 3D spatialization, distance attenuation, and environmental effects (reverb zones, occlusion) make players feel present in the world without them consciously noticing.

5. Middleware is your friend - FMOD and Wwise exist so audio designers and programmers can work in parallel. Sound designers author in the middleware tool; programmers fire events from code. This separation is non-negotiable on any team larger than one person.

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Core concepts

The event-driven audio model

Game audio is built on an event system. Game code fires named events (e.g., Player/Footstep, Weapon/Fire, Music/EnterCombat), and the audio middleware resolves those events into actual sounds. This decoupling means:

• Sound designers can swap, layer, or randomize sounds without code changes
• Programmers don't need to know which .wav file plays for a footstep
• Events can carry parameters (surface type, velocity, health percentage) that the middleware uses to select or modulate sounds

Adaptive music architecture

Adaptive music uses one or more of these techniques to respond to gameplay:

| Technique | Description | Best for | |---|---|---| | Horizontal re-sequencing | Rearranges musical sections in real time | Exploration, open-world | | Vertical layering | Adds/removes instrument layers based on intensity | Combat escalation | | Stinger/transition | Plays a short musical phrase to bridge states | State changes (win, lose, discovery) | | Branching | Pre-authored alternate paths at decision points | Story-driven moments |

Most shipped games combine 2-3 of these. Vertical layering + stingers is the most common pattern for action games.

Spatial audio pipeline

The spatial audio pipeline processes each sound source through:

1. Distance attenuation - Volume decreases with distance (linear, logarithmic, or custom curve)
2. Spatialization - Panning across speakers/headphones using HRTF (head-related transfer function) or simple panning
3. Occlusion/obstruction - Raycast from listener to source; muffle if geometry blocks the path
4. Environmental effects - Apply reverb, echo, or filtering based on the room/space the sound is in (reverb zones)

FMOD vs Wwise at a glance

| Aspect | FMOD Studio | Wwise | |---|---|---| | Pricing | Free under $200K revenue | Free under 1000 sound assets | | Learning curve | Lower - familiar DAW-like UI | Steeper - more powerful, more complex | | Strength | Rapid prototyping, indie-friendly | Large-scale projects, AAA pipelines | | Unity integration | First-class plugin | First-class plugin | | Unreal integration | Community plugin | Built-in integration | | Scripting | C/C++ API, C# wrapper | C/C++ API, Wwise Authoring API |

See references/fmod-guide.md and references/wwise-guide.md for setup and API details.

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Common tasks

Set up an audio event system

Create a centralized audio manager that maps game events to middleware calls.

// Unity + FMOD example
public class AudioManager : MonoBehaviour
{
    public static AudioManager Instance { get; private set; }

    private void Awake()
    {
        if (Instance != null) { Destroy(gameObject); return; }
        Instance = this;
        DontDestroyOnLoad(gameObject);
    }

    public void PlayOneShot(string eventPath, Vector3 position)
    {
        FMODUnity.RuntimeManager.PlayOneShot(eventPath, position);
    }

    public FMOD.Studio.EventInstance CreateInstance(string eventPath)
    {
        return FMODUnity.RuntimeManager.CreateInstance(eventPath);
    }

    public void SetGlobalParameter(string name, float value)
    {
        FMODUnity.RuntimeManager.StudioSystem.setParameterByName(name, value);
    }
}

// Usage from game code:
AudioManager.Instance.PlayOneShot("event:/SFX/Explosion", transform.position);

Implement adaptive music with vertical layering

Layer instrument stems that activate based on a game parameter (e.g., threat level).

FMOD Studio setup:
1. Create a Music Event with multiple audio tracks (stems):
   - Track 1: Ambient pad (always playing)
   - Track 2: Percussion (activates at threat > 0.3)
   - Track 3: Brass/strings (activates at threat > 0.6)
   - Track 4: Full orchestra (activates at threat > 0.9)

2. Create a parameter "ThreatLevel" (0.0 to 1.0) on the event

3. Add volume automation on each track tied to ThreatLevel:
   - Track 1: Volume 1.0 across full range
   - Track 2: Fade in from 0.0 to 1.0 between threat 0.3-0.4
   - Track 3: Fade in between 0.6-0.7
   - Track 4: Fade in between 0.9-1.0

// Code side - update the parameter from game state
private FMOD.Studio.EventInstance musicInstance;

void StartMusic()
{
    musicInstance = AudioManager.Instance.CreateInstance("event:/Music/Exploration");
    musicInstance.start();
}

void Update()
{
    float threat = CalculateThreatLevel();
    musicInstance.setParameterByName("ThreatLevel", threat);
}

Configure spatial audio with attenuation and occlusion

// FMOD: Set 3D attributes on a looping sound source
public class AudioEmitter : MonoBehaviour
{
    [SerializeField] private string eventPath = "event:/SFX/Generator_Hum";
    private FMOD.Studio.EventInstance instance;

    void Start()
    {
        instance = FMODUnity.RuntimeManager.CreateInstance(eventPath);
        instance.set3DAttributes(FMODUnity.RuntimeUtils.To3DAttributes(transform));
        instance.start();
    }

    void Update()
    {
        instance.set3DAttributes(FMODUnity.RuntimeUtils.To3DAttributes(transform));
    }

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

For occlusion, raycast from the listener to the source and set a low-pass filter parameter based on hit count:

void UpdateOcclusion()
{
    Vector3 listenerPos = Camera.main.transform.position;
    Vector3 direction = transform.position - listenerPos;
    float distance = direction.magnitude;

    int hits = Physics.RaycastNonAlloc(listenerPos, direction.normalized,
        raycastHits, distance, occlusionMask);

    float occlusion = Mathf.Clamp01(hits * 0.3f);
    instance.setParameterByName("Occlusion", occlusion);
}

Design sound variation for repeated events

Prevent repetition fatigue by using containers and randomization:

FMOD Studio:
1. Create a Multi Instrument inside your event
2. Add 3-5 sound variants (e.g., footstep_01.wav through footstep_05.wav)
3. Set playlist mode to "Shuffle" (avoids consecutive repeats)
4. Add pitch randomization: -2 to +2 semitones
5. Add volume randomization: -1 to +1 dB

Wwise equivalent:
1. Create a Random Container
2. Add sound variants as children
3. Enable "Avoid Repeating Last" with a value of 2-3
4. Add Randomizer on Pitch (-200 to +200 cents) and Volume (-1 to +1 dB)

Set up audio buses and mixing

Organize all game audio into a bus hierarchy for clean mixing:

Master Bus
  |- Music Bus        (baseline: -6 dB)
  |    |- Combat Music
  |    |- Ambient Music
  |- SFX Bus          (baseline: 0 dB)
  |    |- Player SFX
  |    |- Enemy SFX
  |    |- Environment SFX
  |- UI Bus           (baseline: -3 dB)
  |- Voice Bus        (baseline: +2 dB, duck Music by -12 dB when active)

Key mixing practices:

• Duck music when dialogue plays (sidechain the Voice bus to Music bus)
• Set voice limits per event (e.g., max 8 simultaneous footsteps)
• Use snapshot/state systems for context switches (underwater, pause menu)
• Keep headroom: master should peak at -3 to -6 dBFS

Optimize audio for performance

| Technique | Memory savings | CPU savings | When to use | |---|---|---|---| | Compressed formats (Vorbis/Opus) | 80-90% | Slight CPU cost | All SFX except very short sounds | | Streaming from disk | ~100% per sound | Disk I/O cost | Music, long ambiences (>5 seconds) | | Voice limiting | Proportional | Proportional | Any sound that can overlap heavily | | Sample rate reduction (22kHz) | 50% | Minor | Ambient, background, low-frequency | | Sound pooling | Avoids alloc spikes | Avoids alloc spikes | Rapid-fire sounds (bullets, particles) |

Rules of thumb:

• Stream music and long ambiences; load short SFX into memory
• Set voice limits: 4-8 for common SFX, 1-2 for music events
• Use compressed in-memory format for SFX banks
• Budget: aim for under 50 MB total audio memory on console, 100 MB on PC

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Anti-patterns / common mistakes

| Mistake | Why it's wrong | What to do instead | |---|---|---| | Hardcoding audio file paths in game code | Tightly couples code to specific assets; impossible to iterate on sounds without recompiling | Use event-based middleware; reference events by name, never by file | | No sound variation | Players notice repeated identical sounds within 3 occurrences; breaks immersion | Use random containers with 3-5 variants plus pitch/volume randomization | | Music cuts abruptly on state change | Jarring transitions destroy mood; players notice bad music transitions immediately | Use transition timelines, crossfades, or stinger/bridge segments | | Ignoring voice limits | 100 simultaneous explosion sounds will clip, distort, and destroy CPU budgets | Set per-event voice limits with steal behavior (oldest, quietest, or farthest) | | Flat 3D audio (no occlusion) | Sound passing through walls breaks spatial awareness and immersion | Implement raycast-based occlusion with low-pass filtering | | Mixing everything at 0 dB | No headroom causes clipping; no hierarchy means players can't prioritize important sounds | Structure buses with headroom; duck less important buses when critical sounds play | | Loading all audio into memory | Game runs out of memory or has huge load times | Stream long audio; compress short SFX; only load banks needed for current level |

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Gotchas

1. FMOD/Wwise events not releasing cause memory leaks - Creating an EventInstance and calling start() without calling stop() and release() on OnDestroy leaks audio resources permanently. Looping sounds in particular will play forever even after the game object is destroyed. Always pair CreateInstance() with a release() in the cleanup path.

2. Voice stealing can silence the most important sound - If your voice limit steal mode is set to "oldest" or "lowest priority" and you don't assign proper priority weights, the enemy warning sound or boss music can get stolen by ambient birds. Set explicit priority values for every event category and use "lowest priority" steal on non-critical sounds only.

3. Streaming audio from disk introduces frame spikes on seek - Streaming is memory-efficient but seeks cause disk I/O spikes. Enabling streaming on short SFX (under 5 seconds) trades memory savings for CPU/IO cost with no benefit. Stream only music and long ambiences; load short SFX into memory compressed.

4. Occlusion raycasts every frame on all emitters tanks CPU - Running Physics.Raycast per emitter per frame for 50+ active audio sources will consume significant CPU time. Stagger occlusion updates (every 3-5 frames per emitter, not every frame) and use a maximum occlusion check distance to skip distant emitters.

5. Parameter automation curves that are too fast cause audible clicks - Changing a parameter value instantly (e.g., switching ThreatLevel from 0 to 1 in one frame) causes a discontinuity in the audio signal that produces an audible click. Always use smoothed parameter changes with a minimum ramp time of 50-100ms for volume/frequency parameters.

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References

For detailed content on specific topics, read the relevant file from references/:

• references/fmod-guide.md - FMOD Studio setup, C# API, event authoring, parameter automation
• references/wwise-guide.md - Wwise project setup, SoundBank workflow, RTPC, state/switch groups
• references/spatial-audio.md - HRTF, ambisonics, reverb zones, occlusion algorithms, platform differences
• references/adaptive-music.md - Horizontal re-sequencing, vertical layering, transition matrices, implementation patterns

Only load a references file if the current task requires deep detail on that topic.

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Companion check

On first activation of this skill in a conversation: check which companion skills are installed by running ls ~/.claude/skills/ ~/.agent/skills/ ~/.agents/skills/ .claude/skills/ .agent/skills/ .agents/skills/ 2>/dev/null. Compare the results against the recommended_skills field in this file's frontmatter. For any that are missing, mention them once and offer to install:

npx skills add AbsolutelySkilled/AbsolutelySkilled --skill <name>

Skip entirely if recommended_skills is empty or all companions are already installed.