3D Audio

Current surround sound systems offer a good listening experience, but they lack certain elements found in a true live-sound experience. The 3D audio research at AudioLabs seeks to move beyond current surround sound to the more realistic world of 3D audio.

Compared to simple stereo reproduction, current multichannel systems, such as 5.1 or 7.1, offer some “envelopment” of the listener by creating the feeling that the sound production is detached from the loudspeakers. Through use of ambiance, such as room reflections and reverberation, the sound is perceived to be in a more realistic environment. By using an “in the band” mix, where instruments surround the listener, multichannel systems can create a sense of ‘being surrounded by sound’. However, a fundamental limitation of all such surround sound is that it exists only within a horizontal plane, thus there is no height to the sound, as there would be in a live-sound environment.

In contrast to these conventional surround systems, 3D audio systems add height information, via more channels and/or audio objects. This groundbreaking addition improves the sense of realism so much that it becomes difficult for the listener to tell the difference between a recording and a live-music experience.

There are many aspects of 3D audio that AudioLabs researches in order to create the most realistic listening experience possible. One aspect of this research is the number of speakers necessary for creating 3D audio. The 22.2 speaker arrangement offers the best spatial accuracy and quality, but this arrangement is often impractical for general consumer installation. An extension of existing 5.1 and 7.1 systems with four corner height speakers could be one easy-to-install alternative. Further research, including listening tests, is required to assess the subjective audio quality for any possible setup.

Additionally, questions of non-ideal speaker setup require research as well. The upcoming MPEG-H audio standard for delivery of high-quality 3D audio content will include playback rendering to match the received audio to the existing speaker setups. With MPEG-H audio and its related technologies, it will be possible to render audio to speakers wherever they are located and maintain optimal sound quality. It will even include the ability to produce 3D sound, via psychoacoustic processing, on existing 5.1 systems or headphones. AudioLabs helped create the technology that was selected as a basis for this upcoming MPEG-H audio standard.

Another aspect of AudioLabs’ 3D audio research is discovering the ideal production technique for 3D audio. The known production techniques for surround sound do not generalize to 3D sound and thus new techniques must be developed and tested. Tonmeisters and sound engineers experiment with production techniques in order to make the best possible use of 3D sound setups.

AudioLabs 3D audio research activities are conducted in full collaboration with the Audio and Multimedia division of Fraunhofer IIS.