Answers in the perceptual test, noise centered around 1319 Hz (a), 2006 Hz (b), and 2720 Hz (c); for the comparison between PC/FS, FS/PC, PC/FF, and FF/PC configurations, where the first configuration in each pair corresponds to the first presented stimulus. The second configuration is rated on the scale in comparison to the first one, i.e. PC/FS is the comparison of FS with respect to PC. The triangles indicate individual ratings (ratings from the same participant have the same color). The horizontal bars represent the median of each distribution. For ease of reading reasons, small horizontal and vertical offsets are used for displaying the individual answers as black triangles (each answer originally is an integer number between −3 and 3). Answers for stimuli pairs made of identical stimuli (PC/PC, FS/FS, FF/FF) are also shown for checking consistency.