The Audio Engineering Society has published the AES69-2015 standard, providing a framework for the use of binaural and 3D audio in personal music players. The standard describes the format and exchange of spatial acoustics files.
The use of Binaural listening is growing due through smartphones, tablets and other personal entertainment systems delivery of audio via headphones. An understanding of the way that the listener experiences binaural sound, expressed as head-related transfer functions (HRTF), is the key to 3D personal audio. The lack of a standard for the exchange of HRTF data makes it difficult for developers to exchange binaural capture and rendering algorithms effectively. While 3D audio continues to gain popularity among end-users, binaural listening could be the first 3D audio vector with sufficient fidelity of HRTF.
The AES69-2015 standard defines a file format to exchange space-related acoustic data in various forms. These include HRTF, as well as directional room impulse responses (DRIR). The format is designed to be scalable to match the available rendering process and is designed to be sufficiently flexible to include source materials from different databases.
This project was developed in AES Standards Working Group SC-02-08, with the writing group being led by Matthieu Parmentier and principal authors Piotr Majdak and Markus Noisternig. The standard builds upon an earlier project to define a spatially-orientated format for acoustics (SOFA), which aimed at storing HRTF data in a general way, capable of supporting any transfer-function data measured with microphone arrays and loudspeaker arrays.
The use of convolution-based reverberation processors in 3D virtual audio has also grown with the increase of computing power. Convolution-based reverberators help to create a natural listening experience, but also depend on the acoustic quality of the applied directional room impulse response (DRIR).
• Predefined descriptions for the most common measurement set-ups, which are referred to as ‘conventions.’
‘AES69 represents a fundamental piece of architecture for taking personal audio to a new level of performance,’ says AES Standards Committee Chair, Bruce Olson. ‘Using this, product developers will be able to take advantage of transfer-function databases from all over the world to produce a truly immersive 3D audio experience.’
More: www.aes.org/standards
