Luis Miranda

Dominance of head-motion-coupled directional cues over other cues during walking depends upon source spectrum

Listeners who walk past a continuously presented speech sound source emanating from a fixed spatial position will typically experience veridical perception of source location. If, however, walking listeners are fitted with binaural hearing instruments that allow for the signals reaching their ears to be interchanged, left for right and right for left, the sound source is typically reported to be located in a spatial region that is reversed with respect to all three spatial axes: left for right, front for back, and above for below. This result has been taken as evidence for the relative dominance of dynamic interaural directional cues over the spectral directional cues associated with the pinnae of each listener, which should support veridical perception. In order to investigate the relative importance of the spectral energy distribution of the source on the illusory reversals of source location, bursts of broadband noise were presented rather than continuous speech. Under these circumstances, with greater...

Spatial room acoustics descriptors from a concentric source-receiver array: potential applications for auditoria

Electroacoustic transducer arrays, both microphones and loudspeakers, are emerging as promising tools for measuring and evaluating room acoustics – accounting for source directivity and the angular distribution of the received room reflections over time. This study examines the potential of a concentric source-receiver array for characterizing the spatial response of rooms. Using this concept, the acoustic response at a point in a room is represented by a matrix of impulse responses comprising the combined spherical harmonic series for source and receiver. The spatial analysis of this matrix yields the spatial room response for a source of arbitrary directivity and orientation (limited by the spherical harmonic order implemented). The reduction of such data to parameters can be approached in many ways, and this paper considers the mean and standard deviation of diffusivity index for an nth order cardioid source. Measurements from a prototype transducer are presented. In auditoria, this approach could be well suited to the evaluation of acoustic conditions on stage, and should be especially relevant to describing the effect of acoustics on solo performance.

Directional loudness measurements for a multichannel system

Loudness matching listening tests were conducted to quantify the difference in loudness level from a constant signal played from various horizontal directions. The multichannel system used for this tests was a 5‐channel system, set up according to the ITU Recommendation BS.116‐1 Methods for the subjective assessment of small impairments in audio systems including multichannel sound systems and the test signals were octave bands of noise with centre frequencies from 63 Hz to 8000 Hz. These tests were conducted as part of ongoing research for the ITU Recommendation BS.1770 Algorithms to measure audio programme loudness and true‐peak level. The aim of this experiment is to contribute to the design of a loudness meter by providing channel weightings, and results indicate that listeners are more sensitive to the surround channels than the other channels in the mid and high frequency range.

Audio and acoustic design of the University of Sydney’s Indoor Environmental Quality Laboratory

The quality of indoor environments such as commercial offices is affected by many factors, including temperature, humidity, air movement, illumination, ambient sound, and room acoustics. In 2012, a new laboratory was established at the University of Sydney to examine how such factors affect human occupants. In terms of sound, the design of the laboratory has three components: the acoustic design of the testing rooms; the audio system design (for introducing artificial soundscapes); and the design of generic soundscapes to support experimental work in the laboratory. Acoustic design considerations of the laboratory allow for the testing rooms to be configured as high grade office environments. The laboratory has a 24-channel audio system for introducing realistic and potentially complex sound fields in to the testing rooms, both from within and outside the rooms. Parametrically controlled soundscapes have been developed for interior sources (such as building services noise) and exterior sources (such as tr...