The ability to localize sound sources relies on differences between the
signals at the two ears. These differences are also the basis for binaural
unmasking, an improvement in detecting or understanding a sound masked by
sources from other locations. The neurocomputational operation that underlies
binaural unmasking is still a matter of debate. Current models rely on the
cross-correlation function of the signals at the two ears, the neuronal
substrate of which has been observed in the barn owl but not in mammals. This
disagreement lead to the formulation of an alternative coding mechanism where
interaural differences are encoded using the neuronal activity within two
hemispheric channels. This mechanism agrees with mammalian physiology but has
not yet been shown to account for binaural unmasking in humans. This study
introduces a new mathematical formulation for the two-channel model, which is
then used to explain the outcome of an extensive library of psychoacoustic
experiments