Reduction of ambulance siren noise pollution for a patient using feedback active noise control with a virtual sensing technique

An ambulance siren produces a sound pressure level of around 100 dB. This results in continuous exposure of noise inside the ambulance for the patient and further deteriorates the patient’s health. Feedback active noise control (ANC) with virtual sensing technique (VST) has been applied to various applications to minimize noise. The advantage of feedback ANC over feedforward ANC is that it generates its own reference using the error signal. In contrast, feedforward ANC requires a reference to achieve good noise attenuation that can increase the complexity of the algorithm. Furthermore, the VST overcomes the limitation of a limited zone of silence (ZoS). This paper investigates the application of a feedback ANC with VST to reduce the siren noise around patient ears inside an ambulance without any soundproofing. The feedback ANC with VST was tested using recorded ambulance siren noise and achieved up to 23 dB noise attenuation. The results suggest that feedback ANC with VST can be used inside an ambulance to generate a quiet environment around the patient ears.