Unity 6.3 — Audio Module Reference

Last verified: 2026-02-13 Knowledge Gap: Unity 6 audio mixer improvements

---

Overview

Unity 6.3 audio systems:

• AudioSource: Play sounds on GameObjects
• Audio Mixer: Mix, effect processing, dynamic mixing
• Spatial Audio: 3D positioned sound

---

Basic Audio Playback

AudioSource Component

AudioSource audioSource = GetComponent<AudioSource>();

// ✅ Play
audioSource.Play();

// ✅ Play with delay
audioSource.PlayDelayed(0.5f); // 0.5 seconds

// ✅ Play one-shot (doesn't interrupt current sound)
audioSource.PlayOneShot(clip);

// ✅ Stop
audioSource.Stop();

// ✅ Pause/Resume
audioSource.Pause();
audioSource.UnPause();

Play Sound at Position (Static Method)

// ✅ Quick 3D sound playback (auto-destroys when done)
AudioSource.PlayClipAtPoint(clip, transform.position);

// ✅ With volume
AudioSource.PlayClipAtPoint(clip, transform.position, 0.7f);

---

3D Spatial Audio

AudioSource 3D Settings

AudioSource source = GetComponent<AudioSource>();

// Spatial Blend: 0 = 2D, 1 = 3D
source.spatialBlend = 1.0f; // Fully 3D

// Doppler effect (pitch shift based on velocity)
source.dopplerLevel = 1.0f;

// Distance attenuation
source.minDistance = 1f;   // Full volume within this distance
source.maxDistance = 50f;  // Inaudible beyond this distance
source.rolloffMode = AudioRolloffMode.Logarithmic; // Natural falloff

Volume Rolloff Curves

• Logarithmic: Natural, realistic (RECOMMENDED)
• Linear: Steady decrease
• Custom: Define your own curve

---

Audio Mixer (Advanced Mixing)

Setup Audio Mixer

1. Assets > Create > Audio Mixer
2. Open mixer: Window > Audio > Audio Mixer
3. Create groups: Master > SFX, Music, Dialogue

Assign AudioSource to Mixer Group

using UnityEngine.Audio;

public AudioMixerGroup sfxGroup;

void Start() {
    AudioSource source = GetComponent<AudioSource>();
    source.outputAudioMixerGroup = sfxGroup; // Route to SFX group
}

Control Mixer from Code

using UnityEngine.Audio;

public AudioMixer audioMixer;

// ✅ Set volume (exposed parameter)
audioMixer.SetFloat("MusicVolume", -10f); // dB (-80 to 0)

// ✅ Get volume
audioMixer.GetFloat("MusicVolume", out float volume);

// Convert linear (0-1) to dB
float volumeDB = Mathf.Log10(volumeLinear) * 20f;
audioMixer.SetFloat("MusicVolume", volumeDB);

Expose Mixer Parameters

In Audio Mixer window:

1. Right-click parameter (e.g., Volume)
2. "Expose 'Volume' to script"
3. Rename in "Exposed Parameters" tab (e.g., "MusicVolume")

---

Audio Effects

Add Effects to Mixer Groups

In Audio Mixer:

• Click group (e.g., SFX)
• Click "Add Effect"
• Choose: Reverb, Echo, Low Pass, High Pass, Distortion, etc.

Duck Music During Dialogue (Sidechain)

// Setup in Audio Mixer:
// 1. Create "Duck Volume" snapshot
// 2. Lower music volume in that snapshot
// 3. Transition to snapshot when dialogue plays

public AudioMixerSnapshot normalSnapshot;
public AudioMixerSnapshot duckedSnapshot;

public void PlayDialogue(AudioClip clip) {
    duckedSnapshot.TransitionTo(0.5f); // 0.5s transition
    audioSource.PlayOneShot(clip);
    Invoke(nameof(RestoreMusic), clip.length);
}

void RestoreMusic() {
    normalSnapshot.TransitionTo(1.0f); // 1s transition back
}

---

Audio Performance

Optimize Audio Loading

// Audio Import Settings (Inspector):
// - Load Type:
//   - Decompress On Load: Small clips (SFX), loads fully into memory
//   - Compressed In Memory: Medium clips, decompressed at runtime (RECOMMENDED)
//   - Streaming: Large clips (music), streamed from disk

// Compression Format:
// - PCM: Uncompressed, highest quality, largest size
// - ADPCM: 3.5x compression, good for SFX (RECOMMENDED for SFX)
// - Vorbis/MP3: High compression, good for music (RECOMMENDED for music)

Preload Audio

// Preload audio clip before playing (avoid stutter)
audioSource.clip.LoadAudioData();

// Check if loaded
if (audioSource.clip.loadState == AudioDataLoadState.Loaded) {
    audioSource.Play();
}

---

Music Systems

Crossfade Between Tracks

public IEnumerator CrossfadeMusic(AudioSource from, AudioSource to, float duration) {
    float elapsed = 0f;
    to.Play();

    while (elapsed < duration) {
        elapsed += Time.deltaTime;
        float t = elapsed / duration;

        from.volume = Mathf.Lerp(1f, 0f, t);
        to.volume = Mathf.Lerp(0f, 1f, t);

        yield return null;
    }

    from.Stop();
}

Seamless Music Looping

// Audio Import Settings:
// - Check "Loop" for seamless music loops
audioSource.loop = true;

---

Common Patterns

Random Pitch Variation (Avoid Repetition)

void PlaySoundWithVariation(AudioClip clip) {
    AudioSource source = GetComponent<AudioSource>();
    source.pitch = Random.Range(0.9f, 1.1f); // ±10% pitch variation
    source.PlayOneShot(clip);
}

Footstep Sounds (Random from Array)

public AudioClip[] footstepClips;

void PlayFootstep() {
    AudioClip clip = footstepClips[Random.Range(0, footstepClips.Length)];
    AudioSource.PlayClipAtPoint(clip, transform.position, 0.5f);
}

Check if Sound is Playing

if (audioSource.isPlaying) {
    // Sound is currently playing
}

---

Audio Listener

Single Listener Rule

• Only ONE AudioListener should be active at a time
• Usually attached to Main Camera

// Disable extra listeners
AudioListener listener = GetComponent<AudioListener>();
listener.enabled = false;

---

Debugging

Audio Window

• Window > Audio > Audio Mixer
• Visualize levels, test snapshots

Audio Settings

• Edit > Project Settings > Audio
• Global volume, DSP buffer size, speaker mode

---

Sources

• https://docs.unity3d.com/6000.0/Documentation/Manual/Audio.html
• https://docs.unity3d.com/6000.0/Documentation/Manual/AudioMixer.html