Three-dimensional spatial analysis of concert and recital halls with a spherical microphone array

Abstract

The most well-known acoustical parameters -including Reverberation Time, Early Decay Time, Clarity, and Lateral Fraction -are measured using data obtained from omnidirectional or figure-of-eight microphones, as specified in ISO 3382. Employing a multi-channel receiver in place of these conventional receivers can yield new spatial information about the acoustical qualities of rooms, as well as the potential for new parameters that could have greater predictive power in terms of listeners' subjective preferences. In this research, a spherical microphone array was used to measure the room impulse responses of a number of different concert and recital halls. The data was analyzed using spherical harmonic beamforming techniques, along with other direction of arrival estimation algorithms, to understand how the soundfield evolves spatially over time at different points in the room. The results were compared to geometrical acoustic simulations and used to differentiate between listener positions which exhibited similar values for the standard parameters. In addition, new parameters were examined, including soundfield homogeneity and other spatial ratios.

A Multimodal-Sensor-Enabled Room for Unobtrusive Group Meeting Analysis

“…However, our ultimate aim is to have a smart room that is completely unobtrusive and does not require the participants to wear any specific sensors. We are working towards integrating custom 16-channel ambisonic (spherical) microphones [16,17] into the smart room. The 16 channels can be combined differently to point at each of the instantaneous participant locations obtained by the ToF tracking system, allowing us to more clearly understand the focus of attention of participants in the meeting.…”

A comparison of measured room acoustics metrics using a spherical microphone array and conventional methods

“…The spherical configuration of 41 the array enables a convenient way to beamform directional patterns in any direction in 3D space using a 42 spatial Fourier transform and processing the signals in the spherical harmonics domain [1] [2]. In recent 43 years, spherical microphone arrays have begun to be utilized in room acoustics applications to analyze the 44 directional properties of reverberant spaces [3][4][5][6]. Room impulse responses (IRs) measured with spherical 45 arrays have been analyzed to determine the direction of arrival of early reflections in rooms [3,4,5].…”

“…Room impulse responses (IRs) measured with spherical 45 arrays have been analyzed to determine the direction of arrival of early reflections in rooms [3,4,5]. A 46 recent study also evaluated IR measurements obtained in performing arts spaces using a 16-channel 47 spherical microphone array by beamforming the IRs in the azimuthal plane and comparing different 48 audience receiver positions [6]. 49…”

3D Acoustic Map Analysis of the National Theatre of Zagreb

“…By analyzing the IRs recorded by the multichannel spherical array microphone, it is possible to detect the direct sound coming from the position of the sound source placed on the stage, followed by the early and late reflections [41]. Figure 5 shows the direct sound energy at the four representative positions across the audience where the time frame goes from 40 ms to 300 ms, as shown at the bottom of every image.…”