The RASTI method, objective measurements of speech intelligibility

In recent years, there has been increasing interest in objective measurements of speech intelligibility. For rooms with long reverberation time (also those in which sound systems have been installed), it is very useful for control purposes to have a fast objective way of measuring speech intelligibility. RASTI (rapid speech transmission index) is a new standardized method of measuring speech intelligibility, which provides a rating in less than 10 s. The theory and principles of operation will be presented. Measurement results from the “Grundtvigskirken,” which is a Danish church having a very long reverberation time and a recently installed sound system, will be reported.