Intercomparison Measurements of Room
Acoustical Parameters and Measures for Speech Intelligibility in a Room
with a Sound System.
Kurt Eggenschwiler, Laboratory of Acoustics, Empa Materials Science
and Technology, CH-8600 Duebendorf, Switzerland
Rainer Machner, Hearing Technology and Audiology, University of
Applied Science Oldenburg, D-26121 Oldenburg, Germany
J. Audio Eng. Soc., Vol. 53, No. 3, 2005 March, p. 193-204
Abstract:
Intercomparison measurements of room acoustical parameters and speech
intelligibility measures were performed in a 1500 m3 room containing a
sound system. The parameters included the octave-band reverberation
times T20 and T30 averaged over the entire room, the speech
intelligibility indices STI, STI(mod), STI(male), STI(female), RASTI,
and %ALcons, the frequency response in one-third-octave bands, and the
room acoustical parameters EDT, C80, C50, D50, and Ts at various
positions in accordance with ISO 3382. The measurements carried out by
15 participants from Switzerland were compared. As far as can be
ascertained, two main factors appear to be responsible for the spread
in results. On the one hand, the noise disturbances, at times quite
strong, seemed to pose difficulties for the participants. Frequently
too little attention was paid to achieving an adequate signal-to-noise
ratio. Furthermore, for some measurements the results of certain
participants diverged greatly from those of others, partly as a result
of incorrect settings of the instruments. In the measurement analysis
the standard deviations were compared to the perception thresholds.
When the data from a few conspicuous participants were eliminated, the
standard deviations were often within the region of the perception
thresholds.
Audio Engineering Society