Appendix 1—figure 2. Retrieving the primary spectrum from the low-pass filtered DP2 spectrum.

(A) A tone complex with non-equalized primary spectrum (green circles) was rectified and low-pass filtered at 2.5 kHz. From the resulting DP2 spectrum, the primary spectrum was reconstructed (black Xs). (B) Scatter plot comparing the actual primary spectrum entering the rectifier + low-pass filter scheme to the primary spectrum reconstructed from the DP2 spectrum at the output of the low-pass filter.