To cope with the volume of information with which our senses are constantly bombarded, our brains utilise a variety of categorisation strategies to reduce the amount of data it has to process. I’m in the process of setting up some exciting experiments in the acoustics labs at Salford to investigate how categorisation is utilised when our brains process complex acoustic information. I’ll be using methods developed in cognitive psychology to determine how listeners categorise individual sounds in different types of broadcast audio material.
The application of this work is in object based audio, which is the future of broadcast audio. Traditionally, audio content is produced in such a way that the channels of audio information are mapped to a specific loudspeaker layout, such as stereo or 5.1 surround. The limitation of this approach is that the experience of the listener is severely impaired if the reproduction loudspeaker layout does not match the layout for which the audio was produced. Object based audio gets around this by sending each individual audio object (this may be a character’s dialogue, Foley effects, or music) along with information about the object’s position in space and time. Using this information at the receiving end, the audio can be reconstructed in a way that is optimal for the reproduction system; be that headphones, a tablet, or a cinema system. This approach also opens up possibilities for the listener at home to interact with the audio content, which had been explored recently by the BBC, such as choosing which side of the crowd you hear in a football match.
The results of the experiments I’m about to run at Salford will help us to understand what types of objects we need to represent when we store and transmit object based audio, and will lead to experiments exploring the effects different objects types have on the quality of the listener’s experience. This work is part of the S3A project, which is a five year collaborative project involving Salford, Surrey, and Southampton Universities, and BBC R&D that aims to develop immersive 3D audio systems that work in real environments, such as people’s living rooms. The project’s just getting started, so watch this space for more information!