Kazuma Matsushita

Unwanted sounds generated with test tone presentation can spoil extended high-frequency audiometry

Unwanted sounds from a commercially available audiometer were evaluated in terms of their effects on extended high-frequency (EHF) audiometry. Although the manufacturer reported that the audiometer conformed to relevant International Electrotechnical Commission (IEC) standards, the audiograms obtained using the audiometer were erroneous because the subjects had responded falsely to noise generated with the test tone presentation before detecting the test tone. Analyses of acoustic and electric output signals revealed that the audiometer generated most of the unwanted sounds, not the earphones that were used. Based on the measurement results, clinical implications of the measurement results are discussed for conducting more reliable EHF audiometry.

Auditory signals for consumer electronics: Accessible-design approach and international standardization

Auditory signals are often used in human-machine interface of consumer electronics. Those signals are expected to improve the usability and accessibility of such products. This paper reviews accessibility-related standards on auditory signals for consumer products that were established by the Japan Industrial Standards Committee and are being drafted in a Technical Committee of the International Organization for Standardization, ISO/TC 159 “Ergonomics”.

Audio signals in domestic appliances evaluated in terms of the hearing ability of older adults

The audio signals used in domestic appliances currently available on the market in Japan were recorded to identify suitable signals for the hearing ability of older adults. The results of the analysis indicated the following three problems: (1) Some appliances use high‐frequency tones around 4000 Hz. Since these sounds are hard for older adults with presbycusis to hear, it would be better to use signals with lower frequencies. However, the problem here is that if the frequency is lowered, then the signal might be masked by domestic sounds whose power would be greater relative to the low‐frequency signals. (2) The signals used by some appliances are too soft. The intensity of some signals should be adjusted to compensate for the hearing loss among older adults. (3) The sounds used in these appliances are often very similar in terms of both timbre and temporal ringing patterns. That may cause confusion because it is difficult to identify which appliance is signaling.