ACOUSTICS 2020

Particle dampers can suppress structural vibration over a broad range of frequencies, which makes them attractive in comparison to many other passive damping technologies. They constitute a cavity filled with particles. Energy dissipation from particle dampers depends on many parameters including, size of the cavity, diameter of the particles, shape of the damper, filling ratio, material properties of the particles and the volumetric ratio between the cavity and particles. Performance changes with the amplitude of the excitation and, to a lesser extent, the frequency.

The Acoustics Group has collaborated with the Royal Academy of Music since the enforcement of the Control of Noise at Work Regulations in 2008 [1]. Now, the research has turned towards sound exposure of the staff. Sound monitoring in the form of dosimetry was undertaken during practice, rehearsal and performance for eleven members of staff covering seven disciplines: conducting, piano, strings, vocal, jazz, percussion, and brass. In addition, the auditions were measured for the first time to establish a baseline for sound exposure.

The modern primary school pertained for this paper is a past exemplary primary school in Scotland with linear semi-open plan classrooms. Its acoustic environment was viewed as unsatisfactory by the school, despite the acoustic design being generally aligned with recommendations given in some well-recognised documents. This school was looking for improvements, while maintaining its openplan nature was not compromised. This paper describes the assessment of the acoustic environment by onsite measurements and a 3D acoustic modelling for speech intelligibility.

The aim of this work is to evaluate the effectiveness of different types of tool timers for the estimation of daily exposure time for hand-transmitted vibration. The Health and Safety Executive (HSE) previously had little information available to advise on the merits (or otherwise) of tool timers as part of a vibration control program. Duty holders have begun to rely on tool timers to determine their workers’ exposure to hand-arm vibration.

The term “soundscaping” is a relatively recent arrival on the acoustics’ stage, whereas it was commonly used to refer to sonic pieces created by artists. Murray Shaffer championed the idea in his 1977 publication, The Tuning of the World, introducing the idea that ”a total appreciation of the acoustics environment can give us the resources for improving the orchestra of the soundscape” [1]. This approach immediately challenges the established way of dealing with the external sound environment, and at the time and until recently had not been absorbed into mainstream environmental acoustics.

This paper provides a review of a family of methods that have been developed for the prediction of the vibro-acoustic performance of complex systems over a broad frequency range. The methods represent various extensions of the Statistical Energy Analysis (SEA) approach to response prediction [1,2], and the main attributes are: (i) the use of a low number of degrees of freedom in the model, and (ii) the prediction of the response statistics without the need to perform Monte Carlo analysis.

Aircraft are notorious for their large sound profile, yet noise is one of the most significant limiting factors for aviation growth. In 2011 the World Health Organisation identified environmental noise as the second largest environmental health risk in Western Europe [1]. Prolonged exposure to unacceptable noise levels (≥55 dB Lden (day evening-night level)) is linked to conditions including tinnitus, hypertension, coronary heart disease and myocardial infarctions [2].

The need to balance overheating risk and exposure to noise has recently become an increasingly common issue and is now at the forefront of residential building design. This has resulted in the publication of the ‘Acoustics, Ventilation and Overheating: Residential Design Guide’ 1 (hereafter the AVO Guide) in January 2020. This paper presents an overview of the potential for addressing the noise and overheating challenge through the use of emerging technologies and approaches to construction.

It is only very recently that a proper consideration of the internal acoustic environment when mitigating overheating has started to be taken seriously in the UK. Previously this issue has not been addressed by the various regulatory systems, and developers have been reluctant to pay for what they have seen as an unnecessary consideration. The Association of Noise Consultants has produced the criteria and guidance in its draft Acoustics, Ventilation & Overheating: Residential Design Guide.

Performance spaces and fitness developments are commonly designed with floating floors to attenuate the low frequency sound fields which their activities generate. Whilst the natural frequency of the primary structure, floating element and isolation bearings are of critical importance, it is possible that the air trapped below the floating floor can become stiffened by the deflection of the floor, reducing the insertion loss of the system.

The Health and Safety Executive (HSE) are enforcing criminal law against noise and vibration ‘consultants’. This ranging from formal inspections through to written enforcement and prosecution. Enforcement was taken because the work being done by the ‘consultants’ was not at the standard expected: in some cases it lead to duty holders (the HSE’s term for those who operate businesses) taking harmful action.

The purpose of this report is to review the literature on sound distribution in entertainment venues as it pertains to safe-listening practices; that is, the enjoyment of amplified sound without endangerment to hearing health. The report was put together at the request of the Ear and Hearing Care team at the World Health Organization (WHO), as part of a wider body of work to inform the development of a regulatory framework for control of sound exposure in recreational settings.

Over the last two decades, high-speed railways have been developed rapidly in many countries. The main reason for that is that they make a viable alternative to air transportation for short and medium distances, and they produce very low air pollution per passenger. However, as many other means of transportation, high-speed railways are not free of environmental problems. In particular, ground vibrations generated by high-speed railways is one of the major environmental problems that must be mitigated to allow high-speed trains to be used in densely populated areas1.

According to ContactBabel, approximately 780,000 people are employed in agent positions in call centres throughout the UK1 . Our experience of measuring and assessing ambient noise levels and telephone audio levels in a variety of call centres suggests that a substantial number of agents may be exposed to noise exceeding the first or second action level defined in the 2005 Noise at Work Regulations. We have found that high ambient noise levels in densely occupied call centre areas can lead agents to run their headsets at very high levels.

According to BS 4142:20141 , assessments of impact of industrial sound sources on residential amenities must take into account the presence of the acoustic features in the specific sound source, including tonality, impulsivity, intermittency and other perceptible features. Presence of an acoustic feature can be identified using either subjective or objective methods, with preference given to the former.