This paper presents a mathematical analysis of the effects of interchannel amplitude and time differences in two channel (stereophonic) sound systems. The analysis is developed by computing the acoustic conditions at the listener's ears as a function of the stereophonic signal feature. We also present separate approximations of head-related transfer function (HRTF)-based panning according to predefined frequency bands. We attempt to create non-sophisticated models of the stereophonic listening mechanism with approximations in both the time and frequency domains. The models are based upon psychoacoustical theories that present the frequency-dependent relative importance of acoustical cues. Based on the model, we propose new panning methods that can enhance the localization accuracy of conventional panning methods, such as amplitude panning and HRTF-based panning. The localization performances of the new panning techniques are evaluated and compared by means of auditory model simulations and listening tests. Through simulations and listening test results, it is shown that the proposed panning method makes substantial improvements in the localization of virtual sources.