- •Preface
- •Acknowledgments
- •Contents
- •1 Introduction
- •1.1 Auditory Temporal and Spatial Factors
- •1.2 Auditory System Model for Temporal and Spatial Information Processing
- •2.1 Analysis of Source Signals
- •2.1.1 Power Spectrum
- •2.1.2 Autocorrelation Function (ACF)
- •2.1.3 Running Autocorrelation
- •2.2 Physical Factors of Sound Fields
- •2.2.1 Sound Transmission from a Point Source through a Room to the Listener
- •2.2.2 Temporal-Monaural Factors
- •2.2.3 Spatial-Binaural Factors
- •2.3 Simulation of a Sound Field in an Anechoic Enclosure
- •3 Subjective Preferences for Sound Fields
- •3.2.1 Optimal Listening Level (LL)
- •3.2.4 Optimal Magnitude of Interaural Crosscorrelation (IACC)
- •3.3 Theory of Subjective Preferences for Sound Fields
- •3.4 Evaluation of Boston Symphony Hall Based on Temporal and Spatial Factors
- •4.1.1 Brainstem Response Correlates of Sound Direction in the Horizontal Plane
- •4.1.2 Brainstem Response Correlates of Listening Level (LL) and Interaural Crosscorrelation Magnitude (IACC)
- •4.1.3 Remarks
- •4.2.2 Hemispheric Lateralization Related to Spatial Aspects of Sound
- •4.2.3 Response Latency Correlates of Subjective Preference
- •4.3 Electroencephalographic (EEG) Correlates of Subjective Preference
- •4.3.3 EEG Correlates of Interaural Correlation Magnitude (IACC) Changes
- •4.4.1 Preferences and the Persistence of Alpha Rhythms
- •4.4.2 Preferences and the Spatial Extent of Alpha Rhythms
- •4.4.3 Alpha Rhythm Correlates of Annoyance
- •5.1 Signal Processing Model of the Human Auditory System
- •5.1.1 Summary of Neural Evidence
- •5.1.1.1 Physical Characteristics of the Ear
- •5.1.1.2 Left and Right Auditory Brainstem Responses (ABRs)
- •5.1.1.3 Left and Right Hemisphere Slow Vertex Responses (SVRs)
- •5.1.1.4 Left and Right Hemisphere EEG Responses
- •5.1.1.5 Left and Right Hemisphere MEG Responses
- •5.1.2 Auditory Signal Processing Model
- •5.2 Temporal Factors Extracted from Autocorrelations of Sound Signals
- •5.3 Auditory Temporal Window for Autocorrelation Processing
- •5.5 Auditory Temporal Window for Binaural Processing
- •5.6 Hemispheric Specialization for Spatial Attributes of Sound Fields
- •6 Temporal Sensations of the Sound Signal
- •6.1 Combinations of Temporal and Spatial Sensations
- •6.2 Pitch of Complex Tones and Multiband Noise
- •6.2.1 Perception of the Low Pitch of Complex Tones
- •6.2.3 Frequency Limits of Missing Fundamentals
- •6.3 Beats Induced by Dual Missing Fundamentals
- •6.4 Loudness
- •6.4.1 Loudness of Sharply Filtered Noise
- •6.4.2 Loudness of Complex Noise
- •6.6 Timbre of an Electric Guitar Sound with Distortion
- •6.6.3 Concluding Remarks
- •7 Spatial Sensations of Binaural Signals
- •7.1 Sound Localization
- •7.1.1 Cues of Localization in the Horizontal Plane
- •7.1.2 Cues of Localization in the Median Plane
- •7.2 Apparent Source Width (ASW)
- •7.2.1 Apparent Width of Bandpass Noise
- •7.2.2 Apparent Width of Multiband Noise
- •7.3 Subjective Diffuseness
- •8.1 Pitches of Piano Notes
- •8.2 Design Studies of Concert Halls as Public Spaces
- •8.2.1 Genetic Algorithms (GAs) for Shape Optimization
- •8.2.2 Two Actual Designs: Kirishima and Tsuyama
- •8.3 Individualized Seat Selection Systems for Enhancing Aural Experience
- •8.3.1 A Seat Selection System
- •8.3.2 Individual Subjective Preference
- •8.3.3 Distributions of Listener Preferences
- •8.5 Concert Hall as Musical Instrument
- •8.5.1 Composing with the Hall in Mind: Matching Music and Reverberation
- •8.5.2 Expanding the Musical Image: Spatial Expression and Apparent Source Width
- •8.5.3 Enveloping Music: Spatial Expression and Musical Dynamics
- •8.6 Performing in a Hall: Blending Musical Performances with Sound Fields
- •8.6.1 Choosing a Performing Position on the Stage
- •8.6.2 Performance Adjustments that Optimize Temporal Factors
- •8.6.3 Towards Future Integration of Composition, Performance and Hall Acoustics
- •9.1 Effects of Temporal Factors on Speech Reception
- •9.2 Effects of Spatial Factors on Speech Reception
- •9.3 Effects of Sound Fields on Perceptual Dissimilarity
- •9.3.1 Perceptual Distance due to Temporal Factors
- •9.3.2 Perceptual Distance due to Spatial Factors
- •10.1 Method of Noise Measurement
- •10.2 Aircraft Noise
- •10.3 Flushing Toilet Noise
- •11.1 Noise Annoyance in Relation to Temporal Factors
- •11.1.1 Annoyance of Band-Pass Noise
- •11.2.1 Experiment 1: Effects of SPL and IACC Fluctuations
- •11.2.2 Experiment 2: Effects of Sound Movement
- •11.3 Effects of Noise and Music on Children
- •12 Introduction to Visual Sensations
- •13 Temporal and Spatial Sensations in Vision
- •13.1 Temporal Sensations of Flickering Light
- •13.1.1 Conclusions
- •13.2 Spatial Sensations
- •14 Subjective Preferences in Vision
- •14.1 Subjective Preferences for Flickering Lights
- •14.2 Subjective Preferences for Oscillatory Movements
- •14.3 Subjective Preferences for Texture
- •14.3.1 Preferred Regularity of Texture
- •15.1 EEG Correlates of Preferences for Flickering Lights
- •15.1.1 Persistence of Alpha Rhythms
- •15.1.2 Spatial Extent of Alpha Rhythms
- •15.2 MEG Correlates of Preferences for Flickering Lights
- •15.2.1 MEG Correlates of Sinusoidal Flicker
- •15.2.2 MEG Correlates of Fluctuating Flicker Rates
- •15.3 EEG Correlates of Preferences for Oscillatory Movements
- •15.4 Hemispheric Specializations in Vision
- •16 Summary of Auditory and Visual Sensations
- •16.1 Auditory Sensations
- •16.1.1 Auditory Temporal Sensations
- •16.1.2 Auditory Spatial Sensations
- •16.1.3 Auditory Subjective Preferences
- •16.1.4 Effects of Noise on Tasks and Annoyance
- •16.2.1 Temporal and Spatial Sensations in Vision
- •16.2.2 Visual Subjective Preferences
- •References
- •Glossary of Symbols
- •Abbreviations
- •Author Index
- •Subject Index
Chapter 5
Model of Temporal and Spatial Factors
in the Central Auditory System
In this chapter, a workable neuropsychological signal processing model is proposed that links temporal and spatial acoustic factors with their corresponding perceptual attributes via observable response properties of the central auditory system. In the model, temporal factors that are observed to be associated with left cerebral hemisphere responses may be extracted from central autocorrelation processors. Similarly, spatial factors observed to be associated with the right hemisphere may arise from the action of central binaural crosscorrelators in the auditory pathway. Thus, the subjective attributes of sound fields can be described in terms of these temporal and the spatial factors and their corresponding specializations in the two cerebral hemispheres.
5.1 Signal Processing Model of the Human Auditory System
5.1.1 Summary of Neural Evidence
The central auditory signal processing model is based on several related sets of acoustical, mechanical, and neural evidence: the physical characteristics of the ear, auditory brainstem responses, slow vertex responses, EEG recordings, and MEG recordings.
5.1.1.1 Physical Characteristics of the Ear
First, it is interesting to note the fact that the human ear sensitivity to the sound source in front of the listener is essentially formed by the physical system from the source point to the oval window of cochlea. The sound transmission path includes its propagation through external space as well as human head and pinna, the external canal, and the eardrum and the ossicular bone chain. The transfer function of this cascade system largely determines the sensitivity of the human ear. Because the A-weighting network is modeled to represent this sensitivity function, for the sake of practical convenience, it can be utilized in place of the transfer function of the physical system.
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5 Model of Temporal and Spatial Factors in the Central Auditory System |
5.1.1.2 Left and Right Auditory Brainstem Responses (ABRs)
Characteristics of typical human auditory brainstem responses (ABR) imply:
1.Amplitudes of ABR waves Il,r and IIIl,r correspond roughly with the respective sound pressure levels at the two ears as a function of the horizontal angle of incidence to the listener, ξ as shown in Fig. 4.2a, c.
2.Amplitudes of waves IIl,r and IVl,r correspond roughly to sound pressure levels as a function of the contralateral horizontal angle, ξ as shown in Fig. 4.2b and d. The left–right reversal of ABR wave amplitudes implies three major interchanges of neural signal flow between the left and right auditory pathways (Fig. 4.3).
3.Analysis of these ABR peaks suggest that they reflect neuronal responses at the level of the inferior colliculus that correspond well with interaural correlation magnitude values (IACCs, Figs. 4.5–4.7).
5.1.1.3 Left and Right Hemisphere Slow Vertex Responses (SVRs)
Recordings of left and right slow vertex responses (SVRs) have revealed the following:
4.The left and right peak-trough amplitudes of the early SVR, A(P1–N1) reflect left and right hemispheric dominance with respect to temporal and spatial factors, respectively. The temporal factor is the first reflection time-lag t1 (Fig. 4.11) and the spatial factors here are the sensation level SL (Fig. 4.12) and spatial compactness IACC (Fig. 4.13). At first, from a physical viewpoint, we considered classifying sensation level SL (or listening level LL) as a temporalmonaural factor. However, slow vertex responses indicated that SL is right hemisphere dominant. Classification of the LL as a spatial factor is natural because it is measured by the geometric average of sound energies arriving at the two ears (Equation 2.24).
5.Both left and right latencies of the N2 wave covary with interaural correlation magnitudes IACC (Fig. 4.9), and thus these are related to the listener preferences regarding sound diffuseness.
5.1.1.4Left and Right Hemisphere EEG Responses
Analysis of EEG signals recorded from the left and right cerebral hemispheres reconfirmed that
6.Neuronal responses related to first reflection time t1 and later reverberations Tsub are relatively dominant in the left hemisphere (Figs. 4.16–4.19), while those related to the IACC are relatively dominant in the right hemisphere