Listeners with normal hearing (NH) and sensorineural hearing loss (SNHL) were asked to compare pairs of noise stimuli and choose the louder noise in each pair. Each noise was made up of 15, two-ERB (equivalent rectangular bandwidth) wide frequency bands that varied independently over a 12-dB range from one presentation to the next. Mean levels of the bands followed the long-term average speech spectrum (LTASS) or were set to 43, 51, or 59 dB sound pressure level (SPL). The relative contribution of each band to the total loudness of the noise was determined by computing the correlation between the difference in levels for a given band on every trial and the listener's decision on that trial. Weights for SNHL listeners were governed by audibility and the spectrum of the noise stimuli, with bands near the spectral peak of the LTASS noise receiving greatest weight. NH listeners assigned greater weight to the lowest and highest bands, an effect that increased with overall level, but did not assign greater weight to bands near the LTASS peak. Additional loudness-matching and paired-comparison studies using stimuli missing one of the 15 bands showed a significant contribution by the highest band, but properties other than loudness may have contributed to the decisions.

Data obtained in sample-discrimination tasks indicate that subjects place high weight on the lowest and highest frequencies when making judgments concerning the loudness of broadband stimuli. In an effort to determine whether these judgments are truly based on loudness, six subjects with normal hearing were tested in a loudness matching task where the stimuli consisted of 15 bands of noise, each two critical bands wide, or 15 tones at the center frequencies of those noise bands. In addition to comparing all combinations of 15-component noise and 15-component tone stimuli, subjects adjusted the level of 15-component stimuli to equate them in loudness with stimuli missing the lowest, middle or highest component. This was done for stimuli with equal levels for each component and for levels approximating the long term average speech spectrum. Noise stimuli had to be increased by 2.5 dB to be equal in loudness to tonal stimuli. Full bandwidth stimuli had to be decreased in level by 1.4–1.8 dB to be equal in loudness to stimuli missing the highest frequency band or tone. The effect was smaller if the middle component was missing and near zero if the lowest component was missing. [Work supported by NIH.]