ABSTRACT
Subjective measurements provide the entry point to understanding the psychoacoustic relationships. In controlled listening tests and in measurements, electronic devices in general, speaker wire and audio-frequency interconnection cables are found to exhibit small to non-existent differences. If the frequency responses of the devices being compared are identical, as in most electronic devices, loudness balancing is a task easily accomplished with a simple signal like a pure tone and a voltmeter. Perceived loudness depends on both sound level and frequency, as seen in the well-known equal-loudness contours. The hearing threshold data are shown superimposed on the family of equal-loudness contours, the sound levels at which different pure tones are judged to be equally loud. Each time the loudspeaker that won the mono tests also won the stereo tests, but not as convincingly, because in stereo everything tended to sound better. Tests were done that included mono, stereo and multichannel presentations.
