Abstract:
Densification of housing is leading to the construction of more medium-rise, multi-tenancy buildings. In order to minimise material and building cost but achieve the required structural performance, it is attractive to use light-weight construction methods based on materials such as plasterboard and light timber framing (LTF). LTF con-struction is traditional in NZ but where it is used for inter-tenancy walls in medium and high density housing we are finding that transmission of noise between dwellings is becoming a major problem. In this exploratory research project we report on initial encouraging results of using Helmholtz Resonators (HR) to reduce the loss of insulation in lightweight cavity walls in the region of the mass-air-mass (MAM) resonance. This resonance results from the two wall leaves enclosing an air spring on which they can resonate. Often the wall insulation in this critical low frequency band is significantly poorer than if it were only a single leaf wall. Such walls, although meeting code requirements, can be subjectively undesirable when insulating against sounds from low frequency loudspeakers which are a ubiquitous feature of modern living. So far the work has comprised using 3D printed HRs tuned to the MAM resonance and coupled into an experimental cavity to demonstrate proof of principle.