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The use of Tranquility Rating for urban spaces

Idczak Julia, Juros Klara, Chojak Aleksandra, Mleczko Dominik

Vibrations in Physical Systems

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2021

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Vol. 32, nr 1

art. no. 2021104

EN

The Tranquility Rating coefficient (TR) is a tool proposed for assessing the quality of urban green areas, which considers both visual and acoustic aspects. This paper aims to verify how the proposed TR coefficient works for the assessment of the audiovisual quality of a typical urban space in a vicinity of an arterial road. Three different versions of the same urban space are considered: loud and visually unappealing (current state), quiet and visually unappealing (after considerable traffic reduction), and visually appealing and quiet (after redesigning). The values of noise levels required for the calculation of TR are taken from the noise maps based on the in-situ measurements, and the values of the percentage ratio of the features which are natural or man-made but contained within the visual scene (NCF) are taken from a survey conducted in the research. The results show that for the urban areas, even with very low noise levels, the TR is described as “unacceptable”. This may indicate the need for introducing an amendment for TR to be used in typical urban areas.

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Stopband effect and sound transmission loss of periodic locally resonant structures

Juros Klara, Kras Aleksander, Kamisiński Tadeusz

Vibrations in Physical Systems

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2021

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Vol. 32, nr 1

art. no. 2021105

EN

This paper investigates the theoretical aspects of sound attenuation of periodic structures with locally resonant elements. The stopband effect in frequency characteristics of infinite periodic structures created by the resonant elements is investigated. The dispersion curves calculation procedure is described in details with the influence of resonance frequency and mass of added locally resonant structure on width of the obtained stopband is investigated. The theoretical formulation for calculation of the sound transmission loss for periodic structure is derived. The performance of the structure with locally resonant elements is evaluated based on dispersion curves obtained for an infinite periodic structure and transmission loss calculated for finite structure is conducted.

3

Coupled speakers directivity measurements for small acoustic omnidirectional source development

Chojnacki Bartłomiej, Kamisiński Tadeusz, Juros Klara, Kaczor Daniel

Vibrations in Physical Systems

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2019

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Vol. 30, nr 1

art. no. 2019128

EN

Acoustic monopole construction is unsolved task, which engineers try to solve for many years. In the past they constructed many innovative solutions, such as spark or laser-gap sound sources, but those concepts caused many equipment troubles. It is impossible to select type of the measurements signal for this kind of sound sources, also any sparks and laser beams can provide strong electromagnetic distortions around the operation zone. In current state of art we are trying to provide non-standard solutions while traditional omnidirectional sound source, based on spatial configuration of electroacoustic transducers, is not described correctly and can be expanded. Paper presents concept of acoustic monopole source based on coupled configuration for electrodynamic loudspeakers, similar to isobaric setup but non-constant volume between the speakers. By using FEM modelling we will present directivity patterns and project ideas, describing how overall results corresponds with geometrical parameters of speaker configuration and parameters. Presentation summary contain results of prototype device directivity patterns measurements. Received characteristics shows big potential in using cone-to-cone coupled speaker setup to reach acoustic monopole in frequency range defined by distance between transducers. Achieved knowledge allows to provide broadband, easy to build and small acoustic monopole with many possible applications.