Ray-Traced Audio Reflections and Environmental Acoustic Diffraction in UE5 / Source 2: Edge Cases, Failure Modes, and Root-Cause Debugging

[Liam Perez]

I’ve been digging into ray-traced audio reflections in UE5’s MetaAudio and I’m hitting some real headaches with phonon tracing performance on mid-range GPUs. When scene complexity climbs past a certain triangle count, do you all see the audio HRTF convolution becoming the actual bottleneck, or is it usually the occlusion query pass eating your budget first? I’m specifically trying to understand where the real failure modes are.

For the Source 2 side, how are you folks handling material absorption coefficient mismatches between the audio material graph and the rendering materials? I keep getting phase artifacts around thin geometry where diffraction modeling breaks down, and I’m not sure if it’s a sampling rate issue or the way the acoustic navmesh is being generated. Have you found a mitigation for the edge cases where reflections ghost through geometry that should be fully occluding?

Anybody running this at competitive-refresh latencies without dropping audio thread priority? What’s your practical ceiling for real-time phonon bounces before quality degrades noticeably?

"Keychron Q1 Max (Gateron Jupiter Banana) + Artisan Hayate Otsu Mid"

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