Subjective and objective evaluations of scattered sounds in concert halls

The effects of wall diffusing elements on the perception of sound fields were investigated in 1:10 scale models and a recital hall. Acoustical measurements were carried out in both halls with and without diffusers. The front halves of both side walls in the recital hall were covered by plastic panels and/or absorptive materials. Then the impulse responses recorded in diffusive, reflective, and absorptive conditions were measured in the audience area. The diffusive surfaces of the halls caused a decrease in the coefficient of variation for EDT and an increase of the normalized number of peaks” (Np) at various frequencies. When auditory experiments were conducted for the acoustical preference in the recital hall, it was found that a dominant factor was the Np parameter with different wall surface treatments.