Neurons in the medial superior olive perform a coincidence analysis between inputs from the two ears, as predicted by Jeffress [J. Comp. Psychol. 41, 35-39 (1948)]. Jeffress also correctly predicted inputs to express a range of internal delays for which he invoked axonal delay lines. These, however, cannot explain that the inputs of many binaural neurons differ by a combination of a time delay and a phase shift. This study proposes an alternative source of internal delay. An interaural asymmetry in the activation threshold of the inner hair cell synapses is shown to reproduce the main features of internal delays of binaural neurons.