Real time control of sound pressure and energy density in a mining vehicle cabin

Abstract

Real-time active noise control testing was undertaken in a cabin of a mining vehicle for the purpose of determining the relative effectiveness of energy density control vs sound pressure control. Both tonal and broadband noise over the frequency range 5 to 300Hz were used in the tests. Measurements before and after control were taken close to the error sensors and well away from the error sensors. As expected, higher reductions were achieved close to the error sensors, even when multiple sensors were used. When broadband noise was controlled, the levels at frequencies in the vicinity of the cavity resonances were reduced at the expense of increased levels at other frequencies so that the response spectrum became more flat. Energy density sensing resulted in greater levels of control than pressure sensing at distances further than approximately 300 mm from the error sensors.