http://science.sciencemag.org/content/sci/201/4359/899.2.full.pdf

Phenomenology of perception.

Fourier Acoustics Sound Radiation And Nearfield Acoustical Holography

The first artificial reverberation algorithms were proposed in the early 1960s, and new, improved algorithms are published regularly. These algorithms have been widely used in music production since the 1970s, and now find applications in new fields, such as game audio. This overview article provides a unified review of the various approaches to digital artificial reverberation. The three main categories have been delay networks, convolution-based algorithms, and physical room models. Delay-network and convolution techniques have been competing in popularity in the music technology field, and are often employed to produce a desired perceptual or artistic effect. In applications including virtual reality, predictive acoustic modeling, and computer-aided design of acoustic spaces, accuracy is desired, and physical models have been mainly used, although, due to their computational complexity, they are currently mainly used for simplified geometries or to generate reverberation impulse responses for use with a convolution method. With the increase of computing power, all these approaches will be available in real time. A recent trend in audio technology is the emulation of analog artificial reverberation units, such as spring reverberators, using signal processing algorithms. As a case study we present an improved parametric model for a spring reverberation unit.

Fifty Years of Artificial Reverberation

Head-Related Transfer Function and Virtual Auditory Display: E-Book , Head-Related Transfer Function and Virtual Auditory Display: E-Book , کتابخانه دیجیتال جندی شاپور اهواز

Head-Related Transfer Function and Virtual Auditory Display: E-Book

https://hal.archives-ouvertes.fr/hal-01058575/document

A Survey on Sound Source Localization in Robotics: from Binaural to Array Processing Methods

A computationally efficient 3D real time rendering engine for binaural sound reproduction via headphones is presented Binaural sound reproduction requires to filter the virtual sound source signals with head related transfer functions (HRTFs) To improve humans localization capabilities head tracking as well as room simulation have to be incorporated This yields the problem of high-quality, time-varying interpolation between different HRTFs To overcome this problem a virtual ambisonic approach is used that results in a bank of time-invariant HRTF filter

/pdf/a-3d-ambisonic-based-binaural-sound-reproduction-system-3ko9jl0qm3.pdf

A 3D Ambisonic Based Binaural Sound Reproduction System

Ambisonics with height is a three-dimensional sound field reproduction technique for spherical loudspeaker arrangements surrounding the reproduction area. It employs spherical harmonics up to a given order to expand incident sound fields with a limited angular resolution. The expansion coefficients describe the spatial sound scene. For reproduction, these coefficients are decoded to a set of surrounding loudspeakers. Common decoding approaches either sample the spherical harmonic excitation at the loudspeaker positions or match the excitation modes of a continuous sound field to those of the loudspeakers. For well-designed spherical loudspeaker arrays, both decoding approaches achieve good perceptual localization of virtual sound sources. However, both approaches perform unsatisfactorily with non-uniformly arranged arrays. Sounds from directions with only sparse loudspeaker coverage appear with altered loudness levels. This distracting effect results from variations in the decoded energy. The present article demonstrates an improved decoding technique, which preserves the decoded energy. Using available objective estimators, the localization qualities of these energy-preserving decoders are shown to lie between both common decoding approaches.

Energy-Preserving Ambisonic Decoding

Convincing binaural sound reproduction via headphones requires filtering the virtual sound source signals with head related transfer functions (HRTFs). Furthermore, humans are able to improve their localization capabilities by small unconscious head movements. Therefore it is important to incorporate head-tracking. This yields the problem of high-quality, time-varying interpolation between different HRTFs. A further improvement of human localization accuracy can be done by considering room simulation yielding a huge amount of virtual sound sources. To increase the computational efficiency of the proposed system, a virtual ambisonic approach is used, that result in a bank of time-invariant HRTF filter independent of the number of sources to encode.

/pdf/3d-binaural-sound-reproduction-using-a-virtual-ambisonic-1h1pxfobmt.pdf

3D binaural sound reproduction using a virtual ambisonic approach

The Interaural Time Delay (ITD) is an important binaural cue for sound source localization. Calculations of ITD values are obtained either from measured time domain Head-Related Impulse Responses (HRIRs) or from their frequency transform Head-Related Transfer Functions (HRTFs). Numerous methods exist in current literature, based on a variety of definitions and assumptions of the nature of the ITD as an acoustic cue. This work presents a thorough comparative study of the degree of variability between some of the most common methods for calculating the ITD from measured data. Thirty-two different calculations or variations are compared for positions on the horizontal plane for the HRTF measured on both a KEMAR mannequin and a rigid sphere. Specifically, the spatial variations of the methods are investigated. Included is a discussion of the primary potential causes of these differences, such as the existence of multiple peaks in the HRIR of the contra-lateral ear for azimuths near the inter-aural axis due to multipath propagation and head/pinnae shadowing.

A comparative study of Interaural Time Delay estimation methods.

Spatially Oriented Format for Acoustics: A Data Exchange Format Representing Head-Related Transfer Functions

Markus Noisternig

Papers

A 3D Ambisonic Based Binaural Sound Reproduction System

Energy-Preserving Ambisonic Decoding

3D binaural sound reproduction using a virtual ambisonic approach

A comparative study of Interaural Time Delay estimation methods.

Spatially Oriented Format for Acoustics: A Data Exchange Format Representing Head-Related Transfer Functions