Convention Paper
Some Effects of Equalisation on Sound System Intelligibility & Measurement
AES Convention 115 · Paper 5986 · October 2003
Abstract
Although it is well known that equalising a sound system can significantly affect the perceived sound quality and intelligibility, surprisingly there is little or no information relating to the degree of improvement in intelligibility that can be achieved. Measurement data relating to over 30 sound systems has been reviewed and a number of factors relating to typical response anomalies identified. Large discrepancies were often noted to occur between the measured in-room sound system or loudspeaker response and published anechoic frequency response data. The underlying causes and implications relating to speech intelligibility are discussed. The results of a pilot study illustrating the improvements that appropriate equalisation can produce are presented. It is shown that under some conditions, improvements of over 20 % in speech intelligibility can be achieved. However, it is also noted that none of the current electro-acoustically based measurement metrics, including STI, % Alcons, STIPa or RaSTI correctly indicate the intelligibility improvements that system equalisation produces.
