Noise Reduction Using Smart Speakers

The objective of the project was to demonstrate significant noise reduction for the operators of heavy mining vehicles, using 'smart speakers' which attenuate machine generated noise at the ears of the operator. The term 'smart speakers' refers to the application of an Active Noise Control (ANC) system. Interior noise of several heavy mining vehicles was measured and their cabin noise reduction potential with ANC was rated.

Work completed:

· An extensive survey of onsite vehicle noise levels was completed;

· Some data suitable for predicting ANC performance was collected;

· Predictions of ANC performance show modest reductions in A-weighted noise level;

· An ANC system was built and tested;

· Reductions of 17 dB (linear) were initially estimated for single frequency noise and 5 dB (linear) for broadband noise;

· The system was applied to a diesel utility vehicle. Reductions of 6 dB (linear) were achieved but limited to only 0.4 dB(A) due to the restricted frequency range of the ANC system.

Conclusions Drawn

The low level of A-weighted noise reduction meant a field trial was not pursued. The new generation haul trucks achieve acceptable noise levels using passive treatments that offer better value for money and robustness than active systems.