Multichannel ANC for Motorcycle Helmets
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This thesis investigates the potential of using active noise control (ANC) for attenuating the wind noise experienced by a motorcycle rider at speed. This is done by recording wind noise simultaneously at several locations in a motorcycle helmet, measuring speaker system response (plant) in the helmet, and simulating an active noise control system using the recorded signals and plant. Analysis of the measured signals and plant response is also performed, and implementational challenges not accounted for in simulations are discussed. Results indicate two main obstacles for obtaining attenuation using ANC on motorcycle helmet wind noise: Latency of the plant. The speaker systems ability to generate high sound pressure levels at low frequencies. It is concluded that it is plausible for an ANC system to obtain significant levels of attenuation for motorcycle helmet wind noise, if certain criteria are met. The thesis also gives recommendations for further work and discusses potential improvements on the analysed ANC system.