Software aids acoustic design

A team at Cardiff University is developing software that could help architects improve the acoustic design of indoor spaces where a large number of people meet, talk and interact.

The sound-mapping software is based on human hearing and is being developed to help architects design out unwanted noise.

The new software generates audibility maps of proposed room designs and show up ‘hotspots’ where conversations would not be intelligible if the room were busy.

Architects can then adjust their designs to reduce reverberation until the hotspots are eliminated and audibility is maximised.

Software already exists to help architects predict how a building will perform acoustically for an audience in places such as theatres and concert halls.

‘A lot of work has been done to understand acoustics in places used for public performances,’ said Prof John Culling, project leader. ‘But little has been done to improve the acoustics of day-to-day meeting places, even though this would help all of us in our working and social lives.’

The new software also produces results much more rapidly than other acoustic software. The key to its capabilities is the computational efficiency of the mathematical equation that underpins it.

The mathematical equation treats the binaural system (the use of two ears to perceive sound) as a bank of directional microphones, each of which operates at a different frequency and has a single-directional null (an area where the signal is cancelled out completely).

The equation has been built up using the project team’s research looking at how people take in sound binaurally as it travels round busy rooms and how noise sources are affected by each other. This means it can accurately predict acoustic quality at every point in an indoor space where people are likely to gather.

The architect will be able to call their proposed design onto their computer screen and run the software, which will ask them to specify the locations of the main sound sources in the room.

An audibility map will then automatically be produced and the architect will be able to change the room’s dimensions, its shape or the materials to be used, until hotspots are eliminated. The work will also make a significant difference to areas where audibility is important, such as rail and airport announcement waiting areas.

‘Our objective now is to identify and work with a software company to help us develop the software further and market it,’ said Culling. ‘Hopefully it will be available for architects to use within the next 12 months.’

The three-and-a-half-year project – ‘Effects of Reverberation on Conversation in Rooms’ – is due to run until July 2010. It is receiving EPSRC funding just short of £350,000.