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.

An electrodynamic shaker with an integral force gauge for high-frequency measurements on lightweight structures

2000 ◽  
Vol 214 (10) ◽  
pp. 1285-1297 ◽  
Author(s):  
R M Grice ◽  
R J Pinnington
Keyword(s):  
Frequency Response ◽  
Piezoelectric Material ◽  
Response Function ◽  
High Frequency ◽  
Frequency Response Function ◽  
Dynamic Behaviour ◽  
High Frequencies ◽  
Lightweight Structures ◽  
Electrodynamic Shaker ◽  
Design Construction

The design, construction and calibration of a purpose-built electrodynamic shaker for making frequency response function measurements on lightweight structures at high frequencies (i.e. many kHz) are described. The shaker uses a conventional wire-wound coil onto which is assembled a force gauge. The force gauge is constructed using little more than just a miniature piece of piezoelectric material. The dimensions of the components used to manufacture the shaker are determined by comparing their estimated dynamic behaviour with the estimated mobility of a lightweight perspex test structure. Although such an electrodynamic shaker is not entirely novel, it demonstrates how careful use of basic materials can produce a device that overcomes some limitations of commercial devices at very little cost.

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.

It's only real if you see it: Surround system based 3D sound source modelling in virtual reality

2013 ◽  
Author(s):  
Agoston Torok ◽  
Daniel Mestre ◽  
Ferenc Honbolygo ◽  
Pierre Mallet ◽  
Jean-Marie Pergandi ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Sound Source ◽  
3D Sound

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 Rheology of rounded mammalian cells over continuous high-frequencies

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gotthold Fläschner ◽  
Cosmin I. Roman ◽  
Nico Strohmeyer ◽  
David Martinez-Martin ◽  
Daniel J. Müller
Keyword(s):  
High Frequency ◽  
Mammalian Cells ◽  
Mechanical Response ◽  
Cell Mass ◽  
Low Frequency ◽  
Mass Measurements ◽  
High Frequencies ◽  
Polymer Relaxation ◽  
Continuous Frequency ◽  
Rheological Experiments

AbstractUnderstanding the viscoelastic properties of living cells and their relation to cell state and morphology remains challenging. Low-frequency mechanical perturbations have contributed considerably to the understanding, yet higher frequencies promise to elucidate the link between cellular and molecular properties, such as polymer relaxation and monomer reaction kinetics. Here, we introduce an assay, that uses an actuated microcantilever to confine a single, rounded cell on a second microcantilever, which measures the cell mechanical response across a continuous frequency range ≈ 1–40 kHz. Cell mass measurements and optical microscopy are co-implemented. The fast, high-frequency measurements are applied to rheologically monitor cellular stiffening. We find that the rheology of rounded HeLa cells obeys a cytoskeleton-dependent power-law, similar to spread cells. Cell size and viscoelasticity are uncorrelated, which contrasts an assumption based on the Laplace law. Together with the presented theory of mechanical de-embedding, our assay is generally applicable to other rheological experiments.

Sign in / Sign up

Export Citation Format

Share Document