Some Unity demos may exhibit audio stuttering or crackling, especially during the first few seconds of gameplay or the first time audio events are triggered. This is a common issue when porting to WebGL, and is typically caused by an FMOD DSP buffer configuration that is not ideal for browsers.

Symptons

You may notice:

• Audio stutter during the first gameplay moments
• Crackling when music starts
• Glitches when multiple sound events trigger at once
• Issue improves after playing for a while

This is not a spawnd-specific problem, it is a known WebGL runtime constraint and is usually fixed with a simple FMOD setting adjustment.

Fix: Configure FMOD DSP Buffer for WebGL

FMOD’s default platform settings are often tuned for desktop builds, not browser execution. To prevent stuttering, you should create a dedicated WebGL platform profile inside FMOD and adjust the DSP buffer size.

Step-by-step (Unity)

1. Open Unity
2. Go to: Edit → Project Settings → FMOD Settings
3. Scroll to Platform Specific
4. Duplicate the Default platform settings and create a new target platform called: WebGL
5. Select the new WebGL platform profile
6. Under DSP Buffer Settings, set:
   1. DSP Buffer Length: 2048
   2. (Leave Buffer Count as default unless you have special needs)
   3. ⚠️ Buffer length should always be a power of 2.
      1. Recommended values:
         1. 1024 - Lower latency, may still stutter 2048 - Best balance, usually fixes the issue 4096 - Very safe, slightly higher latency

Below is where this setting lives in Unity:

Why This Happens

Browsers impose stricter timing and scheduling constraints than native platforms. WebGL audio threads are more sensitive to buffer underruns, especially during initial asset loading or first-time event playback. Increasing the DSP buffer gives FMOD more room to stream audio smoothly.

Recommendation Summary

All demos using FMOD should:

• Add a dedicated WebGL platform profile
• Set DSP Buffer Length to 2048
• Test first-play audio behavior before submission

This avoids a poor first impression for players trying the demo on web!