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In open plan office concept, the acoustical distraction problems have become a common problem. Besides, it also needs to deal with thermal issues to have a comfortable work environment. Since the concern of sustainable design is highly discussed, design solutions need to consider energy-saving and environmental health. Commonly sound absorber materials are used to improve acoustics quality. To increase the absorptance, the absorber is installed with air gap and filled with additional insulation e.g. mineral wool. These extra layers potentially give benefit to reduce the thermal transfer when being applied on the envelope walls and ceilings. It is because some of the sound absorber material, air gap, and mineral wool have a low thermal conductivity resulting in lower thermal transfer. This research observes the influences of various sound absorber applications on the acoustics condition and also the impact on the overall thermal transfer value (OTTV and RTTV). The thermal transfer calculation refers to Indonesia National Standard SNI-03-6389-2000, while the rooms acoustics is simulated with Software CATT Acoustics v9 referring to BS EN ISO 3382-3:2012. Absorber materials that been involved are wood wool and PET panel. The result shows that wood wool that applied with 30 mm air gap and additional insulation have reduced the OTTV and RTTV of the room envelope. The initial room condition with Reverberation Time 3.71 second has been reduced to 0.48 second, while OTTV and RTTV are reduced from 48.65 W/m2 and 37.38 W/m2 become 44.24 W/m2 and 14.27 W/m2 respectively.

This paper presents the results of a study in which the performance of palm oil clinker (POC) sandas an alternative acoustic material for controlling noise problems was investigated. The specimens were prepared using the basic mortar mixture of cement-to-river sand ratio of 1:4. The five mixtures used in the study containedPOC sand at the amounts of 0%, 25%, 50%, 75% and 100% of the total weight of the sand. Hardened mortar properties of density and compressive strength as well asacousticperformance were measured. The results show that the specimens containing POC sand gave an average noise reduction coefficient of 0.30, which is larger than the corresponding value of 0.25 for the specimens withriver sand only. The combination of 50% POC and 50%river sand achieved the highest sound absorption coefficient of 0.5 at 315 Hz and 0.4 at 1000Hz. It was also found that although POC sand reduced the compressive strength of specimens, the values obtained was still within the strength limit of non-load bearing structures. The findings suggest that POC sand has the potential to be used in the construction of non-structural wall in reducing the noise pollution.

Textiles are widely used in the automotive industry to provide both comfort to the passengers and an aesthetic appearance to the automotive interior. They can also be used to reduce automotive interior noise, which can make automotive travel safer and more comfortable. Knitted fabrics are used widely in automotive upholstery; however, the sound absorbency of a single layer of a knitted fabric is inadequate for the reduction of automotive interior noise. This paper investigates the sound absorbency of a novel knitted spacer fabric, which can be used in automotive upholstery and has the potential for greater sound absorbency than a conventional plain knitted fabric and its derivatives. The spacer fabric is modelled as a porous sound absorber and its sound absorbency is studied with regard to its structural parameters.

This review covers an alternative material known as natural fibre that can be used to replace synthetic fibre as core material for the production of sound absorber. The review explored natural fibre such as bamboo fibre, arenga pinnata, paddy straw fibre, oil palm mesocarp fibre, and kenaf fibre in terms of acoustic properties such as sound absorption coefficient. It has been found that plenty of research regarding the utilization of natural fibre for sound absorption purposes have been accomplished. The implementation of natural fibre in producing sound absorber brings many environmental benefit as it is much greener compared to existing material such as synthetic fibre. Apart from that, natural fibre does not impose any serious health effect compared to the existing synthetic fibre.

Multiple scattering effects of spherical doublet cavities in rubber are described. Transmitted sound fields of a rubber plate including doublet cavities are measured in a water tank and the resonance frequency of these cavities is obtained. The effects of cavity radius and doublet spacing on the resonance frequency are determined. Theoretical and experimental studies have confirmed that the vibration of doublet cavities is greatly affected by multiple scattering waves, and this result will be useful in designing an underwater sound absorber.