Dynamic Spatial Responsiveness in Concert Halls

Evan Green,Eckhard Kahle

doi:10.3390/acoustics1030031

Abstract

In musical perception, a proportion of the reflected sound energy arriving at the ear is not consciously perceived. Investigations by Wettschurek in the 1970s showed the detectability to be dependent on the overall loudness and direction of arrival of reflected sound. The relationship Wettschurek found between reflection detectability, listening level, and direction of arrival correlates well with the subjective progression of spatial response during a musical crescendo: from frontal at pianissimo, through increasing apparent source width, to a fully present room acoustic at forte. “Dynamic spatial responsiveness” was mentioned in some of the earliest psychoacoustics research and recent work indicates that it is a key factor in acoustical preference. This article describes measurements of perception thresholds made using a binaural virtual acoustics system—these show good agreement with Wettschurek’s results. The perception measurements indicate that the subjective effect of reflections varies with overall listening level, even when the reflection level, delay, and direction relative to the direct sound are maintained. Reflections which are perceptually fused with the source may at louder overall listening levels become allocated to the room presence. An algorithm has been developed to visualize dynamic spatial responsiveness—i.e., which aspects of a three-dimensional (3D) Room Impulse Response would be detectable at different dynamic levels—and has been applied to measured concert hall impulse responses.

Highlights

In musical perception, a proportion of the reflected sound energy arriving at the ear is not consciously perceived
“Dynamic spatial responsiveness” was mentioned in some of the earliest psychoacoustics research and recent work indicates that it is a key factor in acoustical preference
An algorithm has been developed to visualize dynamic spatial responsiveness—i.e., which aspects of a three-dimensional (3D) Room Impulse Response would be detectable at different dynamic levels—and has been applied to measured concert hall impulse responses

Summary

Introduction

A proportion of the reflected sound energy arriving at the ear is not consciously perceived. Investigations by Wettschurek in the 1970s showed the detectability to be dependent on the overall loudness and direction of arrival of reflected sound. Wettschurek found between reflection detectability, listening level, and direction of arrival correlates well with the subjective progression of spatial response during a musical crescendo: from frontal at pianissimo, through increasing apparent source width, to a fully present room acoustic at forte. The perception measurements indicate that the subjective effect of reflections varies with overall listening level, even when the reflection level, delay, and direction relative to the direct sound are maintained. The deliberate variation of intensity—in other words, changes in musical dynamics—is a key ingredient in most musical composition and performance. The connection between musical dynamics and spatial impression was observed in some of the earliest research into psychoacoustics. For the lay-listener, who is perhaps not even aware of this effect, this spaciousness is an unconscious yet pleasant experience.” In certain conditions increases in dynamics can generate an additional dimension of spatial impression for the listener—changes in the spatial impression due to changes in dynamics will be referred to here as “dynamic spatial responsiveness”

Methods

Results

Conclusion