Auditory Distance Perception in Concert Halls and the Origins of Acoustic Intimacy

Intimacy is one of the most intriguing concepts in auditorium acoustics, because it is so elusive and difficult to prove, and yet intuitive and palpable for many. Introduced by Beranek1, intimacy has been regarded as one of the most important aspects of the concert experience. "Acoustical 'intimacy' suggests to the listener the size of the space in which it is performed"1 and implies "that listeners hear the music as thought they are near the performers"2. Beranek proposed initial-time-delay gap (ITDG), the interval between the direct sound and the first reflection (at a central position in the audience area), as an indicator of intimacy, but this simple measure still lacks definitive confirmation from others3.