Room acoustic texture: a methodology for its quantification
* Presenting author
Room acoustic texture is defined by Beranek as the subjective impression listeners derive from the temporal and amplitude patterns of early reflections, at the receiver’s locations inside the room. Traditionally, room acoustic texture was qualified by visual inspection of the room impulse responses (RIR) or counting reflection´s peaks. Taking into account that the reflections in the later part of the RIR follow a Gaussian probability distribution and are totally mixed, we define the early reflections as every amplitude outlier present in a RIR, and mixing time as the instant when their cumulative energy reaches 99% of their total energy. For the amplitude outliers estimation, a moving median filter was applied to the energy time curve and subtracting the result from the full room impulse response. With the outliers impulse response identified, the particular echo density function is defined as its cumulative energy in time. From this processing, a group of descriptors were defined that jointly describe the room acoustic texture, at one point in the sound field. Among these descriptors are the mixing time, expected texture and distance between models. Applications of these descriptors and their spatial standard deviation in rooms seem to be very broad, describing their temporal fine-structure.