Measuring timbre discrimination with cross-faded synthetic tones

Abstract

The identification and discrimination of timbre are essential features of music perception. As timbre differences appear as multidimensional cues, the spectral shape, the spectral fluctuation, and the rise time are the most dominating parameters of timbre in normal-hearing listeners. We developed a psychoacoustical test to determine the timbre discrimination abilities using only the spectral difference as a cue. Therefore, a synthetically generated tone continuum was used in an adaptive alternative forced choice paradigm. The spectral difference was modified by cross-fading the tones adaptively, depending on the listeners' response which allows very precise determinations of the just noticeable difference (JND). We measured the JND for the spectral difference with 18 normal-hearing listeners. The results confirm the applicability of the test to measure timbre discrimination with the spectral difference as solely cue. Further, the portability of the test to further dimensions of timbre is discussed.