Peak concentration of the cross-correlation function when the background is babble and the SNR is 0 dB. The abbreviations “AVoc,” “Comb,” and “Mix” indicate the outputs of the auditory vocoder, the comb-filter, and the original mix, respectively. “Target” and “Background” are the original target speech and background sounds. So, for example, “AVoc-Target” indicates the output of the auditory vocoder was cross-correlated with the clean target speech.