Spatial impression for very different spaces. The influence of the space features on the acoustic parameters recommended by ISO 3382

The standard ISO 3382 is the most important reference for concert hall acoustic characterization; nevertheless there are still different aspects to study in order to apply it for acoustic design. The ISO standard defines spatial impression parameters and the measurement methods; particularly it suggests the figure of eight microphone in order to detect lateral arrivals of the sound reflections. Many authors have measured the parameters of ISO 3382, but about them not definitive conclusions are achieved. In order to investigate these parameters and to find new interpretation of the results, further measurements in very different spaces are carried out. The authors define other spatial parameters as strength lateral parameters that are calculated by acoustical signals detected by dummy head. The different strength parameters of the both left and right ears are compared each other in order to quantify the effective differences between the arrivals of the sound by left and right direction. The authors want to investigate the differences between the parameters in terms of spatial features influence and frequency dependence. Three different spaces are investigated: two courtyards of different shape and dimensions and a regular shape closed space. The investigated parameters are strength indexes: late lateral relative sound level, LG (late lateral strength), as defined in the ISO 3382, and further parameters as lateral strengths and the new dummy ear strengths.