Auralisation of Finite Difference Time Domain Simulations of Sonic Crystal Noise Barriers in an Urban Environment
Regular paper
The University of York
Tuesday 2 june, 2015, 10:40 - 11:00
0.3 Copenhagen (49)
Abstract:
Sonic crystals have been presented previously as both a potential type of noise barrier, and as a form of
sonic art aimed at enhancing the perception of an urban soundscape. Most simulations of such structures
are evaluated based on a measure of Insertion Loss – the spectral attenuation imparted on a sound source
due to the insertion of the structure under investigation between source and receiver. Although this gives
an indication as to the noise attenuation performance for a barrier, it gives little qualitative information as
to how results might be perceived when considered in the context of the soundscape in which a sonic
crystal might be placed. This is particularly important if the device, through its design, is intended to
enhance a given soundscape, rather than mitigate against its negative, or noisy, aspects. This paper
presents a finite difference time domain simulation of 2-D and 3-D periodic structures suitable for use as
sonic crystal noise barriers. The impulse responses obtained from these simulations are used to filter
typical audio source material recorded from an urban environment resulting in a number of auralisations
that can be used to evaluate the effects of such structures on a typical soundscape. A perceivable
difference listening test is used to determine how effective these 2-D and 3-D periodic structures are at
making a significant change in the source material. Results confirm that there are significant perceivable
differences imparted due to the sonic crystal structures used, under the assumed limitations of these
evaluations having taken place under laboratory conditions and where the duration of the source material
does not exceed that of the average auditory short-term memory. Further work will explore whether these
differences are significant under more natural listening conditions.