Perception of stereophonic effect as a function of frequency

A literature study and listening tests have been conducted to contribute to an understanding of the stereophonic effect as a function of frequency. The literature study failed to reveal tests showing loss of stereophonic direction for any part of the audio spectrum and pointed to arrival time difference of the transient portion of sound waves as the significant contributor to stereophonic perception. Tests employing actual program material with a specially developed Stereo Spectrum Selector showed the extreme lower frequencies to have equal or superior directional content to the higher frequencies. The perception loss at any frequency may be of a quantitative nature rather than strictly related to certain wavelengths. Test results and consideration for future developments suggest adoption of full frequency stereophonic systems.