ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06
3pAA1. Preliminary values of clarity and intelligibility for small
auditoria, meeting, and teleconference rooms.
Angelo J. Campanella
Campanella Assoc. & ACCULAB, 3201 Ridgewood Dr., Columbus, OH 43026
Clarity (C80) and intelligibility (D50), normally measured for large
auditoria, provide an alternative to reverberation time (RT60) to evaluate the
acoustical performance of many critical smaller rooms. A Larson Davis 2900 real
time analyzer and sound level meter was used to record a rapid sequence of
octave band spectra from impulsive sound. A PC program was written to
extract this data from the LD2900 and process it into C80, D50, and TCT values.
Experimental values were obtained in ten different rooms including auditorium,
church, theater, lab, chapel, gym, music, rehearsal, teleconference, and living
rooms. Room qualities varied from good through those in need of correction for
the intended room use. Measured quantities were compared with opinions on
existing room performance to provide preliminary desirable ranges of C80, D50,
and TCT according to room use.