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This paper reviews the literature on critical listening education. Broadly speaking, academic research in this field is often limited to qualitative descriptions of curriculum and studies on the effectiveness of technical ear training. Furthermore audio engineering textbooks often view critical listening as secondary to technical concepts. To provide a basis for the development of curriculum and training, this paper investigates both academic and non-academic work in the field. Consequently a range of common curriculum topics is advanced as the focus areas in current practice. Moreover this paper uncovers pedagogical best practice for training sequence and the use of sounds/sight within instruction. A range of specific instructional activities, such as technical ear training, is also explored, thus providing insights into training in this field. Beyond a direct benefit to pedagogues, it is hoped that this review of the literature can provide a starting point for research in critical listening education.
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This article investigates the impact of two commonly used Head-Related Transfer Function (HRTF) processing/modeling methods on the perceived spatial accuracy of binaural data by monitoring changes in user ratings of non-individualized HRTFs. The evaluated techniques are minimum-phase approximation and Infinite-Impulse Response (IIR) modeling. The study is based on the hypothesis that user-assessments should remain roughly unchanged, as long as the range of signal variations between processed and unprocessed (reference) HRTFs lies within ranges previously reported as perceptually insignificant. Objective assessments of the degree of spectral variations between reference and processed data, computed using the Spectral Distortion metric, showed no evident perceptually relevant variations in the minimum-phase data and spectral differences marginally exceeding the established thresholds for the IIR data, implying perceptual equivalence of spatial impression in the tested corpus. Nevertheless analysis of user responses in the perceptual study strongly indicated that variations introduced in the data by the tested methods of HRTF processing can lead to inversions in quality assessment, resulting in the perceptual rejection of HRTFs that were previously characterized in the ratings as the "most appropriate" or alternatively in the preference of datasets that were previously dismissed as "unfit." The effect appears more apparent for IIR processing and is equally evident across the evaluated horizontal and median planes.
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This article proposes a system for object-based six-degrees-of-freedom (6DoF) rendering of spatial sound scenes that are captured using a distributed arrangement of multiple Ambisonic receivers. The approach is based on first identifying and tracking the positions of sound sources within the scene, followed by the isolation of their signals through the use of beamformers. These sound objects are subsequently spatialized over the target playback setup, with respect to both the head orientation and position of the listener. The diffuse ambience of the scene is rendered separately by first spatially subtracting the source signals from the receivers located nearest to the listener position. The resultant residual Ambisonic signals are then spatialized, decorrelated, and summed together with suitable interpolation weights. The proposed system is evaluated through an in situ listening test conducted in 6DoF virtual reality,whereby real-world sound sources are compared with the auralization achieved through the proposed rendering method. The results of 15 participants suggest that in comparison to a linear interpolation-based alternative, the proposed object-based approach is perceived as being more realistic.
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Disembodied electronic sounds constitute a large part of the modern auditory lexicon, but research into timbre perception has focused mostly on the tones of conventional acoustic musical instruments. It is unclear whether insights from these studies generalize to electronic sounds, nor is it obvious how these relate to the creation of such sounds. This work presents an experiment on the semantic associations of sounds produced by FM synthesis with the aim of identifying whether existing models of timbre semantics are appropriate for such sounds. A novel experimental paradigm, in which experienced sound designers responded to semantic prompts by programming a synthesizer, was applied, and semantic ratings on the sounds they created were provided. Exploratory factor analysis revealed a five-dimensional semantic space. The first two factors mapped well to the concepts of luminance, texture, and mass. The remaining three factors did not have clear parallels, but correlation analysis with acoustic descriptors suggested an acoustical relationship to luminance and texture. The results suggest that further inquiry into the timbres of disembodied electronic sounds, their synthesis, and their semantic associations would be worthwhile and that this could benefit research into auditory perception and cognition and synthesis control and audio engineering.
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The goal of this work is to review and compare different practical methods to obtain a horn’s acoustical impedance. A new alternative method to obtain horn acoustical impedance is introduced and described. A comparison between several methods of measuring horns’ acoustical impedance and finite element analysis is shown. A one-dimensional matrix model is also used for the horn impedance derivation. The acoustical transfer functions of two different horns are measured and compared with the finite element analysis results. A derivation of the axisymmetric exponential horn’s matrix coefficients is provided.
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