Audibility of pure tones presented against domestic sounds: Comparison of ratings between young and older adults for auditory-signal design

Abstract

The audibility of pure tones presented against typical domestic sounds was investigated in a psychoacoustic experiment conducted with young and older listeners. The sound pressure levels of pure tones were varied at several signal-to-noise ratios to find a range of auditory signals that are audible and comfortably loud in noisy conditions. Ratings of the listeners were analyzed in terms of Aweighted sound pressure levels and 1/3 octave band levels of the target tones and background noises. The results revealed that both listener groups assigned similar ratings to various combinations of pure tones and domestic sounds. However, when the tone frequency was 2,000 Hz or higher, older listeners needed a higher tone level to attain a certain level of audibility. On the basis of the results, the authors propose sound-level ranges of auditory signals for consumer products intended for users of various ages and for users who might have age-related hearing loss.

Audibility evaluation of triangle-wave tones presented against domestic sounds: Comparison with the audibility of pure tones

“…A method for determining the sound pressure level of auditory signals for consumer products, which was based on the authors' study [1], has been established as an ISO standard [3]. The results of the present study revealed that the level of auditory signals could be made lower than that described in the standard.…”

“…The ratings of listeners were analyzed in the same way as was done in the previous study [1]. That is, the psychometric function that relates the five tone levels to the listeners' ratings for each combination of target tone and background noise was obtained for the two age groups separately.…”

“…The measurement method is summarized below. Further details are described in [1]. Stimuli Background noises were typical sounds generated by the following electric appliances or by a person doing housework, which were adopted from a sound library [2]: (1) washing dishes at a sink and (2) a ventilation fan in the kitchen, (3) a washing machine, (4) a hair dryer, (5) running water from a shower in the bathroom, (6) a television set, and (7) a vacuum cleaner in the living room.…”

“…In an earlier study [1], the authors investigated the audibility of pure tones presented with a variety of domestic sounds in order to design auditory signals of consumer products. Using the results, they determined a range of sound levels, as a function of tone frequency, at which the tone was detectable and comfortably loud, under noisy conditions, for product users including older people with age-related hearing loss.…”

“…Schematic illustration of stimulus presentation: a ¼ b ¼ 1 s. Median audibility ratings of target tones, pure tones in[1], and triangle-wave tones in the present study. The signal-to-noise ratio (SNR) was measured in terms of (a) A-weighted sound pressure level and (b) the level in the 1/3 octave band of fundamental frequency of target tone.…”