In this paper, we examined the effectiveness of carrying out sound field evaluations by conducting articulation tests using a tri-syllable sound source with the rate of speech varied between four patterns based on the results of envelope analysis of conversational speech and evaluating the results comprehensively for the purpose of evaluating speech transmission properties in room sound fields. We carried out the measurement of ″ease of hearing″on a psychological scale and tri-syllable articulation tests with varied speech rates in various room sound fields with differing echo-diagram response properties and specifically studied the effects of reflected sound on hearing, while conducting comparative examinations of correspondence to test results on a psychological scale. As a result, we found that there was a favorable correspondence between tri-syllable articulation evaluation with varied speech rates and the″ease of hearing″as well as wide range of application to various room sound fields. We, furthermore, considered criteria for the evaluation of tri-syllable articulation tests with varied speech rates from the standpoint of assuring intelligibility from the correspondence of word intelligibility.
