Audible reflection density for different late reflection criteria in rooms

摘要

For reasonably accurate but practical auralizations, some simplifications andrnapproximations are needed. The main issue in the present investigation is that thernreflection density of a room impulse response, in theory, increases so fast as a quadraticrnfunction of the elapsed time, even assuming only specular reflections. Therefore in thisrnstudy, the upper threshold for audible reflection density is investigated for four differentrntransition times of 25, 50, 75, and 100 ms through a headphone listening test. Binauralrnimpulse responses and speech signals simulated in three rooms with differentrncharacteristics (an empty office, a lecture room, and an auditorium) are used as stimuli.rnSubjects are asked to increase/decrease the reflection density of a stimulus until theyrncannot distinguish it from the stimulus that follows the theoretical reflection density for therndifferent transition times in the three rooms. When using binaural impulse responses, thernupper limit of the audible reflection density turns out to be limited to 2800 reflections perrnsecond. For speech signals, the maximum audible reflection density is shown to be as low asrn300 reflections per second, regardless of the room and transition time.