The effect of simulated Doppler frequency changes on detectability of complex tones

The detectability of frequency changes designed to simulate the Doppler effect for moving sound sources has been well documented in the literature (Chowning, 1977; Ericson, 2001; Kaczmarek, 2005, Getzmann, 2008, and Pörschmann & Störig, 2009). The current study was designed to determine whether the presence of Doppler frequency shifts have a measurable effect on the detectability of complex sounds. Detection thresholds for single sinusoids with frequency changes ranging from the frequency DL to a full octave are compared with those for complex tones with selected components frequency modulated to simulate Doppler effects. A one-interval, adaptive tracking paradigm using the SIAM procedure (Kaernbach, 1991) was used to determine three points on the psychometric functions so that detection thresholds and slopes could be compared. For single component signals, the direction of frequency change and the span of the frequency sweep appear to have an effect on detectability. Results for complex tones require further explanation. [Work supported by a contract from CDO Technologies, Dayton, OH.]