A 现象 whereby the 感知 of a moving 声波 varies 底/基于 on its 位置 with respect to the 听众 As it approaches a 听众 it is 感知（认为） at a 较高 频率 and as it moves away a 较低 one This may be attributed to the 感知（认为） 感觉 of shorter wavelengths 特定 a close 近 and longer ones further away 底/基于 on Dictionnaire des 艺术 médiatiques http //www dictionnairegram org