Perceptually Optimised Sound Zones for Future Spatial Audio

Often, two people in a single room want to listen to different items of audio. It may be that one person is watching television whilst the other is listening to the radio, or even that one plays a computer game whilst the other reads in silence. The obvious solution to this would be for all individuals to wear headphones, however this dramatically increases isolation (not just in acoustic terms), is impractical if more than one person wants to listen to either source, and could be uncomfortable over an extended period.

It would be great if we could create ‘zones’ of sound: areas within a room or other environment, where only one of the audio signals could be heard. In other words, reproducing sound in specific zones whilst minimising spill into other zones. An example is shown below of a living room containing two sound zones, A and B, with the remaining space being either a quiet area, or an area where the reproduced sound is relatively unimportant.

This project is unique in the way that it combines engineering (to create the sound zones) and psychoacoustics (to evaluate and predict the perceived quality). It has been funded by Bang and Olufsen and the Engineering and Physical Sciences Research Council and aims to unlock the creative potential of 3D sound and deliver to listeners a step change in immersive experiences.

The engineering research is being conducted by staff and students from the Centre for Vision, Speech and Signal Processing, in collaboration with engineers from Bang and Olufsen. They have developed methods to create sound fields where the audio is concentrated on the corresponding sound zones, with minimal spill into other zones.

The psychoacoustic research is being conducted by staff and students from the Institute of Sound Recording, in collaboration with psychoacousticians from Bang and Olufsen. They have determined the most appropriate perceptual factors when listening interfering signals in a sound zone, and have developed models in order to predict the performance of a system in a perceptually-relevant way.

The video below includes interviews with a number of the project contributors, as well as a binaural demonstration of one of the resulting sound zone systems. Headphones for listening are recommended.

Details on the project can be found at the University of Surrey website and S3A Future Spatial Audio.