A Preliminary Study for a ‘Music Intelligibility’ Test for Rooms

In order to get more useable evaluations of the acoustics of rooms for music it would seem to be important to have a test which is the musical equivalent of a speech intelligibility test. This paper reports on several experiments carried out to find the effects of sound pressure level difference on duration discrimination using pairs of tones with a view to using this as a possible basis for such a test. Experiments were also carried out to evaluate the relative contribution of amplitude envelopes on the perception of sound duration.

Pairs of signals were presented with the difference in SPL, shape of rise/decay, and duration. Duration judgements for the signals were investigated together with those of the standard stiniuli. From the results of experiments, it was found that the duration discrimination tasks are affected by a SPL difference of more than 3 dB. It appears that the more information a signal carries the more effect there is on duration judgement, i.e., the more the signal envelope is modulated in a space by the presence of room acoustic parameters the greater the difficulty in determining the duration of the sounds in music or speech. From the results it would seem that discrimination between sounds could form a useful measure of how good a room is for musical performances.