Study of the Effects of the Doppler Shift on Perceived Noisiness

Abstract

Subjective judgments of the effects of Doppler shifts on perceived noisiness were made by 20 college students in an anechoic chamber. The stimuli heard in the test included both recorded and simulated air-craft flyovers. Computer controlled generation of the simulated flyovers permitted independent variation of the source frequency, apparent altitude, amplitude, and Doppler patterns. Data collection was governed by a computer-based adaptive technique known as Parameter Estimation by Sequential Testing (PEST). The results of the tests will be discussed and a recording of one of the simulated flyover noises will be presented. The major finding was that effective perceived noise level (EPNL) is a fairly accurate predictor of flyovers containing Doppler shifts, except perhaps at altitudes of less than 500 ft, for which flyovers it underestimates apparent noisiness. Compensation for the risetime of the stimuli (an onset correction) did not improve the accuracy of prediction provided by EPNL.