Abstract Archive Detail
Demonstrating Phase with Binaural Hearing from Stereo Speakers
A presentation from the 2015 Winter Meeting: San Diego, California
A relatively simple electronic circuit duplicates an audio signal shited by a variable phase difference. When these two signals are delivered to a pair of stereo speakers, the apparent sound source position can be manipulated. When teaching about waves, phase is often an abstract and difficult subject for students. This is partly because there are many situations in which phase is irrelevant; waves carry information and energy without reference to phase. Binaural hearing offers a case where phase matters. For frequencies below approximately 1000 Hz (that is, wavelengths longer than the width of a human head), directional hearing is primarily based on the phase difference (or time delay) between the sound reaching the two ears. Classroom demonstration of the effect offers an interesting, concrete phenomenon with which to motivate discussion of phase differences. Deeper investigation can illustrate limitations on stereo imaging based on interference patterns.