# 5. Audio Mixer Pitfalls Part of [[Audio Mixers and Character Audio]]. Previous: [[4. Footsteps and Surface Audio]]. Next tutorial: [[Interactable Audio]]. > [!note] Verification status > Items marked (Manual) or (reference) were read in the 6000.5 docs on 2026-11-07; the rest are practical experience - verify in your project. **No code compiled.** | Symptom | Cause | Fix | |---|---|---| | Snapshot changes no longer affect a fader | `SetFloat` locked the exposed parameter (Manual/reference) | Don't expose snapshot-controlled params; or `ClearFloat` to hand control back | | Volume slider feels "all at the top" | Linear 0..1 written straight into dB | `20 * log10(v)`, floor at -80 dB (Part 2) | | My mix changes vanished | Edited while the wrong snapshot was selected | Check the highlighted snapshot before every edit | | Changes made in Play mode are kept/lost unexpectedly | **Edit in Play Mode** overrides the snapshot system while playing (Manual) | Turn it on only to mix live; note what you changed | | Pause snapshot never fades in | Mixer `updateMode = Normal` at `timeScale = 0` | `AudioMixerUpdateMode.UnscaledTime` | | UI clicks silent in pause menu | `AudioListener.pause = true` | `ignoreListenerPause = true` on UI sources | | Reverb tail cut off / effects stop when nothing plays | Auto mixer suspend after silence (Manual: waits ~1 s then uses loudness measurement) | Tune or disable **Auto Mixer Suspend** on the mixer asset | | Distortion/crackle on loud moments | Group sums above 0 dB | Leave headroom (-6 dB on SFX), limiter/compressor on Master | | Random sounds drop out in busy scenes | Exceeded real voices; low-priority sources virtualized (reference) | Set priorities (Part 3), pool and cap sources ([[Interactable Audio]]), raise real voices in Project Settings > Audio carefully | | Double footsteps | Distance events *and* animation events; or blend-out events | Pick one source; guard with clip weight (Part 4) | | Footsteps don't change on terrain | Terrain uses TerrainLayers, not PhysicsMaterials | Map TerrainLayer -> surface (Part 4) | | Group effect affects only some sounds | Sources not routed (Output = None goes straight to listener) | Audit with the mixer's VU meters; route everything, even UI | | Mixer group lookup returns wrong group | `FindMatchingGroups` matches substrings (reference) | Unique names or exact-match filter | | 3D attenuation seems to ignore the mixer | Distance attenuation happens at the source, before the mixer (Manual) | Expected - use source rolloff for distance, mixer for category | ## Platform notes - **Meta Quest 2:** every DSP effect costs CPU on a mobile SoC. Prefer one shared reverb on a send/return (Part 1.6) over per-source `AudioReverbFilter`s; keep real voices modest; profile with the Audio profiler module. Quest projects target Unity 6.3 LTS ([[0.Choosing a Unity Version]]) - re-check the effect list there, as this series cites 6000.5 pages. See [[5.Quest 2 Performance and Rendering]]. - **Web:** the 6000.5 Manual has a dedicated Web audio page and states the new scriptable audio pipeline is not supported on Web. Check the Web audio page before relying on mixer effects in a browser build. ## Docs - Audio Mixer inspectors (Edit in Play Mode, exposed params, auto suspend): https://docs.unity.com/en-us/engine/6000.5/manual/audio/mixer/inspectors - `AudioMixer.SetFloat`: https://docs.unity3d.com/6000.5/Documentation/ScriptReference/Audio.AudioMixer.SetFloat.html - `AudioSource.priority`: https://docs.unity3d.com/6000.5/Documentation/ScriptReference/AudioSource-priority.html - Audio profiler module: https://docs.unity.com/en-us/engine/6000.5/manual/audio/profiler - Web audio: https://docs.unity.com/en-us/engine/6000.5/manual/platform-specific/webgl/develop/audio