The Symmetry of Faces (original) (raw)
Related papers
2014
In contrast to two other multichannel sound-field synthesis techniques, Higher Order Ambisonics (HOA) and Wavefield Synthesis (WFS), Discrete Multichannel Simulation (DMS) has distinct advantages in the display of three-dimensional virtual acoustic sound fields for human listeners. In particular, it is the impact of listener head movements on reproduction fidelity that is the primary concern, although the influence of static head acoustics on the displayed sound field is another critical factor. Whereas movement of the listener's head outside of the 'sweet spot' for HOA can result in dramatic failure in terms of both spatial and timbral performance of a sound-field display system, given a large number of loudspeakers, a value of the DMS system is that the configuration of simulated sources and reflections is fixed on each of the respective loudspeakers even though the absolute angles vary with head translation and rotation. Experiences in the design and evaluation of thr...
Perceptual Soundfield Reconstruction in Three Dimensions via Sound Field Extrapolation
ICASSP 2019 - 2019 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2019
Perceptual sound field reconstruction (PSR) is a spatial audio recording and reproduction method based on the application of stereophonic panning laws in microphone array design. PSR allows rendering a perceptually veridical and stable auditory perspective in the horizontal plane of the listener, and involves recording using near-coincident microphone arrays. This paper extends the PSR concept to three dimensions using sound field extrapolation carried out in the spherical-harmonic domain. Sound field rendering is performed using a two-level loudspeaker rig. An active-intensity-based analysis of the rendered sound field shows that the proposed approach can render direction of monochromatic plane waves accurately.
A geometrical approach to room compensation for sound field rendering applications
In this paper we propose a method for reducing the impact of room reflections in sound field rendering applications. Our method is based on the modeling of the acoustic paths (direct and reflected) from each of the loudspeakers of the rendering system, and a set of control points in the listening area. From such models we derive a propagation matrix and compute its least-squares inversion. Due to its relevant impact on the spatial impression, we focus on the early reflections part of the Room Impulse Response, which is conveniently estimated using the fast beam tracing modeling engine. A least squares problem is formulated in order to derive the compensation filter. We also demonstrate the robustness of the proposed solution against errors in geometric measurement of the hosting environment.
Three-Dimensional Sound Field Reproduction Using Multiple Circular Loudspeaker Arrays
IEEE Transactions on Audio, Speech & Language Processing, 2011
Three-dimensional spatial sound field reproduction enables enhanced immersive acoustic experience for a listener. Recreating an arbitrary 3-D spatial sound field using a practically realizable array of loudspeakers is a challenging problem in acoustic signal processing. This paper exploits the underlying characteristics of wavefield propagation to devise a strategy for accurate 3-D sound field reproduction inside a 3-D region of interest with practical array geometries. Specifically, we use the properties of the associated Legendre functions and the spherical Hankel functions, which are part of the solution to the wave equation in spherical coordinates, for loudspeaker placement on a set of multiple circular arrays and provide a technique for spherical harmonic mode-selection to control the reproduced sound field. We also analyze the artifacts of spatial aliasing due to the use of discrete loudspeaker arrays in the region of interest. As an illustration, we design a third-order reproduction system to operate at a frequency of 500 Hz with 18 loudspeakers arranged in a practically realizable configuration.
An Investigation Into the Real-Time Manipulation and Control of Three-Dimensional Sound Fields
University of Derby Doctoral Thesis, 2004
This thesis describes a system that can be used for the decoding of a three dimensional audio recording over headphones or two, or more, speakers. A literature review of psychoacoustics and a review (both historical and current) of surround sound systems is carried out. The need for a system which is platform independent is discussed, and the proposal for a system based on an amalgamation of Ambisonics, binaural and transaural reproduction schemes is given. In order for this system to function optimally, each of the three systems rely on providing the listener with the relevant psychoacoustic cues. The conversion from a five speaker ITU array to binaural decode is well documented but pair-wise panning algorithms will not produce the correct lateralisation parameters at the ears of a centrally seated listener. Although Ambisonics has been well researched, no one has, as yet, produced a psychoacoustically optimised decoder for the standard irregular five speaker array as specified by the ITU as the original theory, as proposed by Gerzon and Barton (1992) was produced (known as a Vienna decoder), and example solutions given, before the standard had been decided on. In this work, the original work by Gerzon and Barton (1992) is analysed, and shown to be suboptimal, showing a high/low frequency decoder mismatch due to the method of solving the set of non-linear simultaneous equations. A method, based on the Tabu search algorithm, is applied to the Vienna decoder problem and is shown to provide superior results to those shown by Gerzon and Barton (1992) and is capable of producing multiple solutions to the Vienna decoder problem. During the write up of this report Craven (2003) has shown how 4th order circular harmonics (as used in Ambisonics) can be used to create a frequency independent panning law for the five speaker ITU array, and this report also shows how the Tabu search algorithm can be used to optimise these decoders further. A new method is then demonstrated using the Tabu search algorithm coupled with lateralisation parameters extracted from a binaural simulation of the Ambisonic system to be optimised (as these are the parameters that the Vienna system is approximating). This method can then be altered to take into account head rotations directly which have been shown as an important psychoacoustic parameter in the localisation of a sound source (Spikofski et al., 2001) and is also shown to be useful in differentiating between decoders optimised using the Tabu search form of the Vienna optimisations as no objective measure had been suggested. Optimisations for both Binaural and Transaural reproductions are then discussed so as to maximise the performance of generic HRTF data (i.e. not individualised) using inverse filtering methods, and a technique is shown that minimises the amount of frequency dependant regularisation needed when calculating cross-talk cancellation filters.