We introduce a novel modulation of broadband sounds which eliminates correlations between all frequency pairs close to the tinnitus frequency, to reduce cross-frequency neural synchrony and thereby quieten tinnitus. Fifty-three unselected participants completed a blinded randomised crossover trial, which was run completely online using their computers or smartphones, comparing active to perceptually-near-identical sham stimuli, comprising two 6-week listening periods and 3-week washout periods. Results showed a significant, persisting, reduction in self-rated tinnitus loudness after the active (p = 0.012), but not sham (p = 0.916) intervention. Tinnitus distress scores decreased in both listening periods, indicating tolerability of the intervention and trial process. Due to its automation, generalisability across tinnitus types, and deliverability with generic hardware, this intervention could be made available to most of the worldwide tinnitus community at minimal cost. Next steps involve optimising the intervention parameters to maximise efficacy, and development of a software package for wholescale delivery.