HTC VIVE 3DSP is an audio SDK which provide applications with spatial audio, a key factor for an immersive VR experience. With the HTC VIVE 3DSP SDK, the spatial perception is simulated by specific functions and features, such as head-related transfer functions recording and improvement, higher-order ambisonic simulation of sound direction, room audio simulation, adding background noise floor, real-world acoustic property of distance, geometric and raycast occlusion, Hi-Res audio support, and many other features.
There are a lot of factors that could influence the human perception of audio spatialization, such as interaural time difference, interaural level difference, the human body factors (pinna, head, shoulder and torso), the environment factors (room reflections and reverberation), the distance from sound source to user, and the obstacle occlusion. Based on these factors, the HTC VIVE 3DSP generates immersive and realistic audio perception with the following key features:
Higher Order Ambisonics (HOA) with very low computing power.
Head-Related Transfer Function (HRTF) based on refined real-world modeling (horizontally and vertically) resulting in a better algorithm that is applied to all sound filters and effects.
Room Audio simulates the reflection and reverberation of a real space.
Hi-Res Audio Settings source files and playback.
Distance Model based on real-world modelling.
Geometric occlusion uses no Unity collider and the cover area is calculated by itself
Higher Order Ambisonics (HOA)
Ambisonics is the technology that uses a full-sphere surround sound technique to simulate spatial sound. The 3rd order ambisonics model have been represented in HTC VIVE 3DSP SDK.
The technology simulates the room audio with the early reflection, late reverberation, background noise, environment materials and so on.
There is a sound level decrease during sound transmission in real word. However, the changes are different in different conditions. In HTC VIVE 3DSP SDK, serval decadence models are provided.
The occlusion effect is used to accurately simulate what happens to sound when it encounters an obstacle in its transmission path. Both of mono and binaural occlusion modes could be set up in HTC VIVE 3DSP SDK.
Geometric Occlusion: The geometric occlusion calculates the covering ability by analytical geometry techniques. Since there is no need to use the Unity collider.
Raycast Occlusion: The covering ability of an obstacle is calculated by casting many rays into space and enumerate how many of them are blocked.
The VIVE 3DSP SDK supports room effect, room reverberation and reflection, and acoustic occlusion. It also has spatial effect optimization for VIVE Pro Headphones. However the original VIVE and other HMDs and headphones are also supported.