Modifying STI to better reflect subjective impression

摘要

The Speech Transmission Index (STI) is becoming the universally accepted method for measuring the potential intelligibility of a sound system. However, a number of operating conditions and sound system characteristics seem not to be taken into account by current STI techniques. This paper highlights a number of these conditions and discusses possible modifications to the STI in order to improve its potential use and accuracy. In particular it is shown that frequency response anomalies and restricted system bandwidth can lead to erroneous results under low noise, and reverberant conditions.