Objective room acoustics is an essential part of the evaluation of the acoustics of performance venues. The subjective quality of concert hall acoustics is traditionally formed around various descriptors, such as loudness, reverberance, clarity, definition, and envelopment in the sound field [1]. Well known standardized objective parameters, such as G (strength), T30 (reverberation time), EDT (reverberance), C80 (clarity), and LEF (lateral energy fraction) have been developed to quantify different subjective aspects in the acoustics. However, the general objective measures rely heavily on the statistical properties of the sound fields, thus, they are not suitable for accurately describing the acoustic details in rooms. Instead, they aspire to compress the acoustic information in a small set on numeric values.

Spatiotemporal analysis of room acoustics requires measuring of spatial room impulse responses. Earlier methods have mainly concentrated on visualizing sound intensity vectors, where as a potential downside the contribution of e.g. certain early reflections is obscured. The forward-integrating approach aims to overcome this deficiency. Particularly when used with a large number of source positions on stage, the effect of the hall geometry will be emphasized for features that are relevant for most of the source positions.

The current development stage of the method employs the Spatial Decomposition Method (SDM) [2] in the directional analysis. By applying SDM to a spatial impulse response, we obtain directional information for each sample in a monaural impulse response. From the combination of the monaural pressure and spatial metadata, it is then possible to calculate directional energy histogram over different time windows. The histograms are stacked in the visualization so that each of the cumulative time frames indicate where the sound energy is arriving to the receiver position around that time.