An illustrative stereo rendering system obtains a contradirectional audio input signal generated by a microphone assembly having a plurality of microphone elements. The contradirectional audio input signal implements a contradirectional polar pattern oriented with respect to a listener. The system also obtains an array of multidirectional audio input signals generated by the microphone assembly. The array of multidirectional audio input signals implements different unidirectional polar patterns that are collectively omnidirectional in a horizontal plane. The system generates a weighted audio input signal by mixing the array of multidirectional audio input signals in accordance with respective weight values assigned to each multidirectional audio input signal. The system then generates, based on the contradirectional audio input signal and the weighted audio input signal, a stereo audio output signal for presentation to the listener. Corresponding systems and methods are also disclosed.