To combat acoustic intrusion, researchers from the University of Auckland have been awarded around $1 million to develop a new type of wall.
Acoustic intrusion, the unpleasant scenario when a neighbour’s noise is projected into someone’s home, is more likely to occur in medium density housing, and can have negative health detriments.
In addition, medium density housing is popular in Auckland and is projected to make up around 30 per cent of the city’s housing by 2050.
This is why the New Zealand Government’s Ministry of Business, Innovation and Employment has awarded NZ$991,000 to a team of mechanical engineers at the University of Auckland’s Faculty of Engineering’s Acoustic Research Centre.
The researchers aim to create a new type or partition material which, with the use of specific materials, can reduce the capacity of a wall to vibrate in response to sound. This would help provide better sound insulation without taking up more floorspace.
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In particular, the researchers are focussing on cutting low-frequency noise, which travels more easily through walls.
“Sometimes it feels like Sting is playing his bass in your living room,” said lead researcher Andrew Hall, adding that he likes Sting’s bass playing “just not at 2am”.
“A wall is vibrated much more easily at low frequencies, where wavelengths can be more than three metres.
“It’s like a giant hand pushing on the wall.”
Achieving effective noise insulation can be challenging and expensive, usually requiring the density, mass or thickness of a partition material to be increased.
The research team aims to use internal mechanisms, called acoustic metamaterials, to push back against the vibration and disrupt the sound waves travelling through walls. They are also investigating the use of Helmholtz resonators to improve the sound insulation.
“They respond much like when we blow over the top of a glass bottle, and so absorb and reflect sound,” Hall said.
3D printing of soft and hard materials will be used to help explore potential designs.
“Despite people decrying the poor quality of multi-family housing in lower socio-economic sectors, there’s little evidence of research groups seeking solutions in the innovative way that we are proposing,” Hall said.
“Our system aims to raise NZ’s sound insulation standards to meet the internationally recognised minimum performance expressed in overseas building codes. More and more people are living in urban settings in close proximity to others, and tackling noise pollution will have enormous benefits for their health and well-being.”