Meta makes audio on Quest more realistic by upgrading HRTF models

Spatial audio works by using a mathematical function called the head-related transfer function (HRTF), which calculates the audio filters applied to each ear to make it sound like it's coming from one in the 3D space around you. Be precise about the sound you make. This is nothing like the basic audio panning used in most non-VR games.

In 2015, Oculus launched an audio SDK using HRTF, which has undergone several improvements over the years, including near-field HRTF, volumetric sources, dynamic room modeling, and even geometry-based sound propagation.

今年早些时候，Meta停用了Oculus Audio SDK，并将其替换为Meta XR Audio SDK。尽管基于相同的核心技术，但实质上只是一个重新品牌，现在它正在进行重大升级。

HRTF varies in individuals depending on the shape of the ears and the distance between them (determined by head size). In fact, Apple allows users to use iPhone TrueDepth face scans to generate custom HRTFs, a feature the new AirPods could take advantage of.

Meta doesn't have a way of measuring your face and ears, so the HRTF it uses is taken as an average for the general population. The current HRTF is based on publicly available data, but Meta claims it has made "substantial investments" in audio research, and over the past few years its researchers have captured larger and more precise HRTF datasets of more than 150 people.

Meta calls the new model based on this new dataset Universal HRTF. The company claims it is able to provide better location and frequency accuracy.

Improved localization means audio sounds more like it's coming from a virtual audio source, "especially when judging altitude," Meta says, while improved frequency accuracy means audio sounds more natural, with "less coloration and filtering ".

Meta said that they conducted user tests on Universal HRTF with more than 100 people, and the average "subjective user preference score" increased from 37 points to 52 points, and the height detection accuracy increased by 81%.

Universal HRTF will be included in the upcoming v55 release of the Meta XR Audio SDK for Unity. To take advantage of Universal HRTF, developers only need to upgrade the SDK and rebuild their applications, no application-side changes are required.