Figure 2.

(A) Shows the power spectra calculated using Welch’s method for the IRN (blue) and complex harmonic (red) 200 Hz stimuli used in the experiment. The spectra were calculated with a 11025-point Hamming window applied with a 10925-point overlap. (B) Shows a zoomed-in view of three of the upper harmonics of the stimuli, illustrating the difference between the “rippled noise” spectrum and a complex waveform made up of discrete harmonics. In particular, the harmonics of the complex waveform are higher in amplitude and more defined in that they show sharper peaks whereas those of the IRN stimuli are more spread out in frequency.