Vipac has addressed the problem of wind noise in unattended blast noise monitoring by developing GustBuster.
The Environmental Noise Monitor from Vipac is a new generation monitor that can be remotely accessed by cellular phone. Easy-to-use, it is portable and solar-powered for remote monitoring and accessing of noise data.
With GustBuster, a lightweight cylindrical windscreen, blast noise can be measured accurately, even under very windy conditions. The device is constructed using weather resistant materials and dramatically reduces the effects of low frequency wind noise. Easy to attach to any monitoring station, GustBuster measures 400mmx400mm.
Low frequency wind noise results from turbulence. Most of the acoustic energy resulting from a blast occurs well below 100Hz. The same region of the spectrum as turbulence. Through testing different types of flow resistant materials in different configurations, Vipac has developed a windscreen to reduce wind turbulence without affecting the accuracy of the blast noise measurement itself.
This device allows identification of acoustic signals as a result of blasting, whilst cutting out wind noise generated by turbulence.
The following graph displays the reduction in wind noise achieved by GustBuster. An overall reduction of 20dB at wind speeds of 50km/h to 70km/h has been demonstrated. GustBuster has a transmission loss to acoustic signals of 0.2dB at 100Hz.