Growth of loudness at 1000 and 3000 Hz

Abstract

Loudness growth at 1000 and 3000 Hz was measured directly [in human subjects] by magnitude estimation and production, and indirectly by loudness matches between tone and wide-band noise and by interfrequency matching. The outcome of the 3 series of experiments did not reveal any systematic difference in shape of the loudness curves at 1000 and 3000 Hz. To a 1st approximation, above about 30 dB SL [sensation level] the loudness functions at 1000 and 3000 Hz were power functions of sound pressure with an exponent close to the accepted ISO [International Organization for Standardization] standard of 0.60 (0.30 re [referred to] sound intensity). Below 30 dB SL both loudness curves became progressively steeper than a simple power function and approached the same limiting slope, re sound intensity, of unity. Consistent with Steven''s calculation system the data showed that loudness equality was achieved when a 3000-Hz tone was about 8 dB below the SPL [sound pressure level] of a tone at 1000 Hz.