Pitch Change in Trills and Vibratos Free

Musically trained subjects adjusted the absolute frequency change in a vibrato, Δf_Vibr, to match the pitch change in a trill having a constant frequency separation, Δf_Trill, between its upper and lower tones. The form of frequency modulation of the sinusoidal signals was a square wave for the trill, and, for the vibrato, either a triangular or a 50% steady‐state trapezoidal wave. Both trill and vibrato had identical center frequencies, f_c, and duration (750 msec). Within the range tested (4–12 Hz), the modulation frequency had no effect on Δf_Vibr. However, the adjusted Δf_Vibr were consistently higher for the triangular modulation of the vibratos. The function relating Δf_Vibr to Δf_Trill was monotonic with an average slope of 1.72 for the triangular vibrato and 1.07 for the trapezoidal vibrato. No difference could be observed as an effect of two different center frequencies (f_c = 705 or 2330 Hz) when frequency ratios Δf_Trill/f_c and Δf_Vibr/f_c were considered. The width of the observers' internal filter was estimated from the data. [Supported by NINDS Grant No. NS03856.]