Growth rate of perceived magnitude as a function of tone-to-noiSe ratio

Abstract

The growth of overall perceived magnitude (loudness and annoyance) of single tones superimposed on broadband-flat, low-pass, and high-pass noise spectra was measured by absolute magnitude estimation (AME). Results disclose that, in contrast to noiseness, loudness and annoyance growth are dependent on the relationship between the frequency of the added tone and the spectral shape of the noise. Tones centered in noise produce nonmonotonic loudness and annoyance growth functions; those added to the noise skirt produce power functions. Detailed analysis reveals that the measured exponents are invariant across tone-to-noise ratio when the tones are positioned within the noise spectrum, but not when they are added to the skirt. A high-frequency tone combined with low-pass noise increases the growth rate of perceived magnitude as tone-to-noise ratio increases. Conversely, the addition of a low-frequency tone to high-pass noise decreases the growth rate of perceived magnitude. The obtained results are qualitatively compatible with excitation patterns known to be evoked by auditory stimuli at high intensities. [Work supported by NASA Langley Research Center.]