Outputs (48)

Extending the Low Frequency Acoustic Centre Concept to Directional Loudspeakers (2023)
Conference Proceeding
Hargreaves, J. (2023). Extending the Low Frequency Acoustic Centre Concept to Directional Loudspeakers.

The Acoustic Centre of a loudspeaker is defined as being the point from which spherical waves appear to radiate. This is useful to know when performing phase, level, or time alignment, for example. For a single driver in a sealed box, it is typically... Read More about Extending the Low Frequency Acoustic Centre Concept to Directional Loudspeakers.

Adventures in High Intensity Acoustic Testing: a Loudspeaker System for Small-Scale Tests (2023)
Conference Proceeding
Hargreaves, J., Hipperson, J., Wong-McSweeney, D., & O'Doherty, N. (2023). Adventures in High Intensity Acoustic Testing: a Loudspeaker System for Small-Scale Tests.

In the space and aerospace industry, there is a need to perform High Intensity Acoustic Testing (HIAT). This aims to recreate in the laboratory, for the purpose of qualification testing, the extreme acoustic environments that designs must survive in... Read More about Adventures in High Intensity Acoustic Testing: a Loudspeaker System for Small-Scale Tests.

Iterative metric-based waveguide optimisation (2023)
Presentation / Conference
MacDonald, L., Oclee-Brown, J., Dodd, M., & Hargreaves, J. (2023, October). Iterative metric-based waveguide optimisation. Paper presented at 155th Audio Engineering Society Convention, New York

A comparison between the high-frequency Boundary Element Method and Surface-Based Geometrical Acoustics (2023)
Journal Article
Hargreaves, J. (2023). A comparison between the high-frequency Boundary Element Method and Surface-Based Geometrical Acoustics. https://doi.org/10.3397/in_2022_1005

The audible frequency range covers many octaves in which the wavelength changes from being large with respect to dominant features of a space to being comparatively much smaller. This makes numerical prediction of a space's acoustic response, e.g. fo... Read More about A comparison between the high-frequency Boundary Element Method and Surface-Based Geometrical Acoustics.

A 'Surface-based' Geometrical Acoustic formulation within a Galerkin Boundary Element framework (2022)
Thesis
Emthyas, A. A 'Surface-based' Geometrical Acoustic formulation within a Galerkin Boundary Element framework. (Dissertation). University of Salford

As sound propagates within a room, it experiences high-order reflection, diffraction, and scattering. This causes the reflection density to increase over time, such that the sound field becomes diffuse and chaotic. Under these conditions, there is li... Read More about A 'Surface-based' Geometrical Acoustic formulation within a Galerkin Boundary Element framework.

Metric-based optimisation of acoustic lenses and waveguides (2022)
Thesis
MacDonald, L. (2022). Metric-based optimisation of acoustic lenses and waveguides. (Dissertation). University Of Salford

This dissertation develops an automated procedure for the design of acoustic waveguides that can support single parameter (1P) wave propagation over a large bandwidth. 1P waves include plane, cylindrical and spherical waves, and the waveguides aim to... Read More about Metric-based optimisation of acoustic lenses and waveguides.

Raytracing in Galerkin Boundary Integral form (2022)
Presentation / Conference
Emthyas, A., & Hargreaves, J. (2022, August). Raytracing in Galerkin Boundary Integral form. Presented at Internoise 2022, Glasgow, Scotland

Raytracing is an established method for computing the late-time part of room impulse responses. But it has the drawback that only very crude Monte Carlo models of boundary scattering and diffraction are possible to include without losing its attracti... Read More about Raytracing in Galerkin Boundary Integral form.

Analysis and control of acoustic modes in cylindrical cavities with application to Direct Field Acoustic Noise (DFAN) testing (2022)
Presentation / Conference
Hargreaves, J. (2022, August). Analysis and control of acoustic modes in cylindrical cavities with application to Direct Field Acoustic Noise (DFAN) testing. Presented at Internoise 2022, Glasgow, Scotland

It is well known that acoustic cavities have frequencies at which certain free-response ‘modes’ of propagation respond especially strongly. In the absence of significant damping, these cause peaks of high SPL in the frequency response as well as spat... Read More about Analysis and control of acoustic modes in cylindrical cavities with application to Direct Field Acoustic Noise (DFAN) testing.

A Boundary Element Method (BEM) Solver for Low Frequency Room Modes (2022)
Presentation / Conference
Cicero, A., & Hargreaves, J. A. (2022, August). A Boundary Element Method (BEM) Solver for Low Frequency Room Modes. Presented at Internoise 2022, Glasgow, Scotland

Room modes are known to be problematic in small critical listening environments. They degrade the acoustic quality at low frequencies, producing peaks and nulls in the frequency domain and ringing in the time domain. The Finite Element Method (FEM) i... Read More about A Boundary Element Method (BEM) Solver for Low Frequency Room Modes.

A time method version of the transfer matrix method (2021)
Journal Article
Steele, K., & Hargreaves, J. (2021). A time method version of the transfer matrix method. https://doi.org/10.25144/13761

Porous absorbers are ubiquitous in acoustics applications. They are, for example, widely used to control reverberation in rooms and cavities, or to provide attenuation in ducts. Because of this, they have attracted significant research effort to be... Read More about A time method version of the transfer matrix method.