1,721,401 research outputs found
Code for Psychoacoustic Metrics used in "Practical Audio System Design for Private Speech Reproduction"
No full textData submitted to support "Practical Audio System Design for Private Speech Reproduction", PhD Thesis, Daniel Wallace</span
Dataset for: A Low-Cost Loudspeaker Array for Personal Audio with Enhanced Vertical Directivity
No full textThis dataset supports the publication: Daniel Wallace and Jordan Cheer A Low cost array for personal audio with enhanced vertical directivity. Presented at Inter-Noise 2020</span
Practical audio system design for private speech reproduction
No full textMulti-zone sound field control allows individuals to listen to personalised audio content whilst sharing a physical space. Applications of this technology include home entertainment, audio reproduction in public spaces such as museums, shops or exhibitions, and providing areas where the privacy of sensitive communication can be safeguarded without the need for physical barriers. The problem of transmitting a speech signal to a single listener and reducing the intelligibility of that signal elsewhere is the focus of the present thesis. The motivation behind the presented experiments and simulations is to identify the practical trade-offs that must be considered in the design of these Speech Privacy Control systems. Conventional personal audio systems use loudspeaker array processing to produce a bright zone for the intended user of the system and a dark zone where silence is desired. However, established performance metrics and system optimisation techniques do not necessarily yield privacy for the target listener, as attenuated speech may remain intelligible within the dark zone. A system is proposed that focusses a synthetic masking signal into the dark zone to selectively reduce the intelligibility of the leaked speech. Privacy is ensured by adjusting the masker to meet predefined constraints on the speech intelligibility in each zone. This design methodology utilises information from speech intelligibility tests and subjective preference evaluations in order to improve the utility and acceptability of such systems for all nearby listeners. In addition to the design of the masking signal, the performance of a speech privacy control system is affected by the loudspeaker array design and the location of the listening zones. These effects are explored using experimental measurements of a loudspeaker array in a room, and the results are used to select two system configurations for additional evaluation using listening tests. The perceived performance of a system is also affected by the surrounding acoustic environment, notably due to reverberation and background noise, which may change over time. The effects of room reverberation are investigated using image source simulations and acoustical measurements within a room, and the performance is evaluated in terms of the achievable level of acoustic contrast, the difference in speech intelligibility between zones, and the masking signal levels that are required to achieve privacy. A proposal is made to further enhance privacy by combining the effects of background noise and artificial masking signals. This method reduces the level of acoustic contrast that is required to achieve a given level of privacy, compared to the case where the masking is provided by the background noise alone
Imperfect speakers
No full textImperfect Speakers is a novel set in Taiwan, about an English young professional, Robyn Anglesea, who hopes to abandon her stressful existence back in London for a more relaxed ex-pat life in the city of Taipei, but, in the process of making that new life successful, encounters many new conflicts with morality, identity and globalization, meeting examples of Taiwanese society at its most superficial and its most profound. Her
failures to deal with these situations lead her into greater troubles, never understanding, until the novel’s climax, that her own attitude to the world is at the root of many of her difficulties. The novel comments on several canonical travel texts, such as The Sun Also Rises and A Passage to India, and uses the contemporary experience of teaching English in Asia as a lens for re-examining their themes. The novel is not yet finished: here is included the first thirty five pages (the opening chapter) of the latest draft, re-written with the feedback from my thesis advisor and classmates taken into consideration, and a little over a hundred pages of the previous draft.M.F.A.by Daniel Wallac
Optimisation of personal audio systems for intelligibility contrast
No full textPersonal audio systems are designed to deliver spatially separated regions of audio to individual listeners. This paper demonstrates a method of personal audio system design which provides a level of contrast in the perceived speech intelligibility between bright and dark audio zones. Limitations in array directivity which would lead to a loss of privacy are overcome by reproducing a synthetic masking signal in the dark zone. This signal is optimised to provide effective masking whilst remaining subjectively pleasant to listeners. Results of this optimisation from a simulated personal audio system are presented
Combining background noise and artificial masking to achieve privacy in sound zones
No full textA private sound zone can be created by focusing a spoken message towards a target listener using a loudspeaker array. In practice, however, the reproduced speech cannot be completely contained within the target zone due to practical limits on the directivity of the array. Despite these limitations, the privacy of the message can be maintained if the leaked speech is sufficiently masked by noise. Two possible sources of this masking noise are considered in this article: the ambient noise in the reproduction environment, and an additional masking signal radiated by the loudspeaker array. The present article demonstrates that the process of designing a private audio system is significantly affected by the presence of ambient noise. A key complication is that temporal fluctuations and spatial non-uniformity in the ambient noise can reduce its effectiveness as a masker. These features also make it more difficult to estimate the corresponding reduction in the intelligibility of speech in each listening zone. To mitigate this spatial and temporal variance, it is proposed that systems should be designed to rely only on the masking provided by the diffuse, quasi-stationary background noise component of the environmental noise. It is shown that when systems utilise a combination of the background noise and an additional, artificial masker, a lower level of acoustic contrast is required from the system, compared to the case where the masking is supplied by the background noise exclusively
Combining artificial and natural background noise in personal audio systems
No full textPersonal audio systems are designed to deliver spatially separated regions of audio to individual listeners. This paper presents a method for improving the privacy of such systems by predicting speech intelligibility in the bright and dark sound zones. A synthetic masking signal reproduced in the dark zone is adapted to provide sufficient privacy and reduce the potential for annoyance by responding to changes in ambient noise. Results from a simulated personal audio system show that the inclusion of artificial masking can improve the performance of an array in terms of intelligibility contrast
Dataset - Figure data for Design and Evaluation of Personal Audio Systems based on Speech Privacy Constraints
No full textCode and data to reproduce figure files in "Design and Evaluation of Personal Audio Systems based on Speech Privacy Constraints" (https://doi.org/10.1121/10.0001065) published in the Journal of the Acoustical Society of America. </span
A low-cost loudspeaker array for personal audio with enhanced vertical directivity
No full textPersonal audio refers to the production of spatially distinct listening zones within a space that is shared by multiple people. This technology can enable each listener to hear their own desired material without affecting others, facilitate private communication in public spaces, or provide independent volume controls when people of different ages watch TV together. This is accomplished using loudspeaker array processing, and the performance of a given system is subject to practical limitations associated with the array, the zonal geometry and the reproduction environment. The directivity of typical line array designs is only controllable in the horizontal plane, with approximately monopole directivity in the vertical direction. This can reduce real-world performance through excitation of the reverberant sound field. To overcome this limitation a design is presented for an eight-channel line array of loudspeakers, with each loudspeaker designed to be directional in the vertical plane. The design uses inexpensive components and the USB audio protocol to lower the barrier to entry into personal audio research and development. In order to form sound zones, input signals must be processed using transfer responses between the array elements and the desired sound zones, and in keeping with the philosophy of cost reduction, two different methods for analytically approximating these responses are compared against anechoic measurements which are expensive to acquire
The design of personal audio systems for speech transmission using analytical and measured responses
No full textPersonal Audio systems can be used to provide information and entertainment content in public spaces. Limitations in array directivity mean that speech information intended for a target region may remain intelligible elsewhere. This compromises privacy for target listeners and could prove distracting or annoying to passive listeners nearby. A system has previously been proposed whereby the intelligibility of this leaked speech is reduced by radiating an artificial masking signal into the dark zone; this masking signal has been optimised to minimise the potential for annoyance whilst achieving a predefined level of intelligibility in each zone, but only free-field responses were considered. In practice, systems located in public spaces will be adversely affected by noise and reverberation. This detriment to system performance can be quantified using engineering measures such as acoustic contrast, although the perceived performance as evaluated by users does not necessarily correspond. The present paper explores the effect of using analytical and measured transfer responses on speech intelligibility and system optimisation using a practical example of a personal audio system in a room
- …
