Modulation of the SRT through the transcranial current stimulation with respect to the sham stimulation (normalised to 0 dB). Results from the behavioural tests are shown as black dots; the error bars represent the standard error of the mean. The LASSO fit, involving only the significant terms, is shown as red line. (A) At a latency of 100 ms, a phase shift of 240° between the applied current and the envelope of the target voice gave the smallest SRT. The SRT at this phase was comparable to that of the sham stimulation. (B) When the latency of the stimulation was 250 ms, the phase shift of 60° produced an SRT that was about 1 dB below that of the sham condition, although the difference was not statistically significant. (C) Stimulation with a direct current yielded the same SRT as the sham stimulation, but a current at an unrelated envelope worsened the SRT significantly by 2 dB.