前方車両存在時の救急車サイレン音の伝搬

抄録

The volume of the siren prepared for an emergency vehicle is 90 dB or more and 120 dB or less at a position 20 m in front of the vehicle. It is supposed to measure at a height of 1 m above the ground of the position of 20m in front of the vehicle. In this study, it is assumed that an ambulance and a vehicle ahead are present. I calculated the sound pressure level around the ambulance and, by sound analysis, checked a decrement point. As a result, it is revealed that the forward sound pressure level of the front vehicle decreases because front vehicle was installed. This is a reflection of the front vehicle, and it is thought that a sound becomes hard to arrive. I was able to confirm a decrement point by the interference of a reflection and two speakers.