scholarly journals Interaural Level Difference Optimization of Binaural Ambisonic Rendering

2019 ◽  
Vol 9 (6) ◽  
pp. 1226 ◽  
Author(s):  
Thomas McKenzie ◽  
Damian Murphy ◽  
Gavin Kearney
Keyword(s):  
Sound Field ◽  
Processing Technique ◽  
Interaural Level Difference ◽  
Impulse Responses ◽  
Reference Dataset ◽  
Spectral Difference ◽  
Listening Tests ◽  
Complex Scenes ◽  
Interaural Level Differences ◽  
Fifth Order

Ambisonics is a spatial audio technique appropriate for dynamic binaural rendering due to its sound field rotation and transformation capabilities, which has made it popular for virtual reality applications. An issue with low-order Ambisonics is that interaural level differences (ILDs) are often reproduced with lower values when compared to head-related impulse responses (HRIRs), which reduces lateralization and spaciousness. This paper introduces a method of Ambisonic ILD Optimization (AIO), a pre-processing technique to bring the ILDs produced by virtual loudspeaker binaural Ambisonic rendering closer to those of HRIRs. AIO is evaluated objectively for Ambisonic orders up to fifth order versus a reference dataset of HRIRs for all locations on the sphere via estimated ILD and spectral difference, and perceptually through listening tests using both simple and complex scenes. Results conclude AIO produces an overall improvement for all tested orders of Ambisonics, though the benefits are greatest at first and second order.

scholarly journals Diffuse-Field Equalisation of Binaural Ambisonic Rendering

2018 ◽  
Vol 8 (10) ◽  
pp. 1956 ◽  
Author(s):  
Thomas McKenzie ◽  
Damian Murphy ◽  
Gavin Kearney
Keyword(s):  
Virtual Reality ◽  
Frequency Response ◽  
Sound Source ◽  
High Frequency ◽  
Sagittal Plane ◽  
Impulse Responses ◽  
Spectral Difference ◽  
High Frequencies ◽  
Listening Tests ◽  
Frequency Reproduction

Ambisonics has enjoyed a recent resurgence in popularity due to virtual reality applications. Low order Ambisonic reproduction is inherently inaccurate at high frequencies, which causes poor timbre and height localisation. Diffuse-Field Equalisation (DFE), the theory of removing direction-independent frequency response, is applied to binaural (over headphones) Ambisonic rendering to address high-frequency reproduction. DFE of Ambisonics is evaluated by comparing binaural Ambisonic rendering to direct convolution via head-related impulse responses (HRIRs) in three ways: spectral difference, predicted sagittal plane localisation and perceptual listening tests on timbre. Results show DFE successfully improves frequency reproduction of binaural Ambisonic rendering for the majority of sound source locations, as well as the limitations of the technique, and set the basis for further research in the field.

scholarly journals Validation and application of three-dimensional auralisation during concert hall renovation

2020 ◽  
Vol 27 (4) ◽  
pp. 311-331
Author(s):  
Lamberto Tronchin ◽  
Francesca Merli ◽  
Massimiliano Manfren ◽  
Benedetto Nastasi
Keyword(s):  
Cross Correlation ◽  
Three Dimensional ◽  
Sound Field ◽  
Musical Instrument ◽  
Impulse Responses ◽  
Acoustic Parameters ◽  
Field Representation ◽  
Sound Fields ◽  
Acoustic Quality ◽  
Fifth Order

During the renovation of auditoria and concert halls, the acoustic quality is normally evaluated from measurements of impulse responses. One possibility for evaluating the acoustic quality from the measurements (the simulations) consists of convolving anechoic music with the measured (or simulated) impulse responses. In this way, a psycho-acoustic test is achieved using a virtual sound field representation. The listening room ‘Arlecchino’ at the University of Bologna includes ambisonics (up to fifth order) and stereo-dipole playback for virtual reproduction of sound in rooms. In this article, the effectiveness of the listening room ‘Arlecchino’ is first analysed, comparing acoustic parameters obtained from binaural impulse responses measured in some opera houses (in Italy) and auditorium (in Japan) with those virtually measured after the virtual reconstruction obtained in the listening rooms. The similarity between real and virtual sound fields, has been evaluated by comparing different acoustic parameters calculated by real and virtual sound fields, in four halls in different configurations, by means of the stereo-dipole method. In the second part of the article, the listening room was used to analyse the variation in interaural cross-correlation measurements in rooms obtained considering different anechoic sound signals convolved with the binaural impulse responses, to quantify the variation of the interaural cross correlation with different motifs. For this purpose, two different musical instrument digital interface musical motifs, very different from each other for their music characteristics, have been considered. Moreover, for each musical motif, different sound characteristics (i.e. different musical instruments) were considered, to consider both the rhythmic and timbre aspect.

scholarly journals Creation of Auditory Augmented Reality Using a Position-Dynamic Binaural Synthesis System—Technical Components, Psychoacoustic Needs, and Perceptual Evaluation

2021 ◽  
Vol 11 (3) ◽  
pp. 1150
Author(s):  
Stephan Werner ◽  
Florian Klein ◽  
Annika Neidhardt ◽  
Ulrike Sloma ◽  
Christian Schneiderwind ◽  
...  
Keyword(s):  
Augmented Reality ◽  
Auditory Perception ◽  
Audio Signal ◽  
Spatial Audio ◽  
Impulse Responses ◽  
Synthesis System ◽  
Perceptual Evaluation ◽  
Listening Tests ◽  
Work Done ◽  
Audio Reproduction

For a spatial audio reproduction in the context of augmented reality, a position-dynamic binaural synthesis system can be used to synthesize the ear signals for a moving listener. The goal is the fusion of the auditory perception of the virtual audio objects with the real listening environment. Such a system has several components, each of which help to enable a plausible auditory simulation. For each possible position of the listener in the room, a set of binaural room impulse responses (BRIRs) congruent with the expected auditory environment is required to avoid room divergence effects. Adequate and efficient approaches are methods to synthesize new BRIRs using very few measurements of the listening room. The required spatial resolution of the BRIR positions can be estimated by spatial auditory perception thresholds. Retrieving and processing the tracking data of the listener’s head-pose and position as well as convolving BRIRs with an audio signal needs to be done in real-time. This contribution presents work done by the authors including several technical components of such a system in detail. It shows how the single components are affected by psychoacoustics. Furthermore, the paper also discusses the perceptive effect by means of listening tests demonstrating the appropriateness of the approaches.

scholarly journals An Optimized Symmetric WENO Method-Based Numerical Simulation of Intense Sound Field Generated by Underwater Plasma Sound Source

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kaizhuo Lei ◽  
Xiaolong Liu ◽  
Ning Li ◽  
Xuchao Fan
Keyword(s):  
Euler Equations ◽  
Sound Source ◽  
Sound Field ◽  
Maximum Error ◽  
Numerical Examples ◽  
Weighted Essentially Nonoscillatory ◽  
The Third ◽  
Calculation Results ◽  
Pulse Sound ◽  
Fifth Order

The intensive pulse sound wave can be generated by the underwater plasma sound source (UPSS) based on the discharge of the underwater high voltage. The distribution of the sound field is prominently nonlinear. In this paper, the sound field of the intensive UPSS is described by the integral two-dimensional axisymmetric unsteady Euler equations firstly. In order to solve the Euler equations numerically, an optimized fifth-order symmetric WENO (weighted essentially nonoscillatory) method based on the three templates is proposed which is called WENO-SYM3. Without increasing the number of candidate templates, a new symmetric template structure can be obtained by expanding the second template and shifting the third one backwards for one space. The method is validated through numerical examples and experiments, and the results show that WENO-SYM3 has a high distinguished accuracy; meanwhile, its nonphysical oscillations are not obvious. The experimental results are basically the same as the calculation results, and the maximum error is around 3%.

scholarly journals Reconstruction of room impulse responses over extended domains for navigable sound field reproduction

2021 ◽  
Author(s):  
Efren Fernandez-Grande ◽  
Diego Caviedes-Nozal ◽  
Manuel Hahmann ◽  
Xenofon Karakonstantis ◽  
Samuel A. Verburg
Keyword(s):  
Sound Field ◽  
Impulse Responses

Reproduction of Phantom Sources Improves with Separation of Direct and Reflected Sounds

2015 ◽  
Vol 40 (4) ◽  
pp. 575-584
Author(s):  
Piotr Kleczkowski ◽  
Aleksandra Król ◽  
Paweł Małecki
Keyword(s):  
Sound Source ◽  
Sound Field ◽  
Angular Separation ◽  
Impulse Responses ◽  
Sound Sources ◽  
Perceptual Effect ◽  
Multichannel Systems ◽  
Virtual Acoustics

AbstractIn virtual acoustics or artificial reverberation, impulse responses can be split so that direct and reflected components of the sound field are reproduced via separate loudspeakers. The authors had investigated the perceptual effect of angular separation of those components in commonly used 5.0 and 7.0 multichannel systems, with one and three sound sources respectively (Kleczkowski et al., 2015, J. Audio Eng. Soc. 63, 428-443). In that work, each of the front channels of the 7.0 system was fed with only one sound source. In this work a similar experiment is reported, but with phantom sound sources between the front loud- speakers. The perceptual advantage of separation was found to be more consistent than in the condition of discrete sound sources. The results were analysed both for pooled listeners and in three groups, according to experience. The advantage of separation was the highest in the group of experienced listeners.

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