Subjective Perception of Seat Dip Attenuation

An investigation has been conducted into the subjective perception of the seat dip effect (a low-frequency attenuation affecting sound travelling at grazing incidence over seating). In a realistic simulation of a concert hall sound field, the threshold of perception was a change of −3.8 ± 0.2 dB in the 200 Hz octave band early energy, from 0 to 80 ms. The threshold was not greatly affected by the presence of reverberation. The size of the threshold means that low-frequency values of monaural early-energy parameters like C ₈₀ are relatively unimportant. On examining measurements made in a rectangular concert hall, it was shown that the seat dip effect is audible at some scats, and that a combination of design methods would be needed to render it inaudible in most cases.