• The Journal of the Acoustical Society of Korea
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• v.39 no.1
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• pp.57-63
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• 2020

The binaural beat is a subjective beating phenomenon due to the frequency difference of sounds heard in both ears, sensed by the human brain. The beating magnitude physically depends on the amplitudes of the two signals with slight different frequencies. Therefore, the binaural beat strength is expected to be affected by the difference in left and right hearing ability. In this study, 34 healthy subjects without hearing loss were chosen. They hear a pure tone sound (450 Hz) at 10 different Sound Pressure Levels (SPLs) (from 50 dB to 27.4 dB) through the one side of ears, while they hear the reference sound (440 Hz, 50 dB) through the other side of ears. Their subjective assessment using a semantic differential method reveals that the binaural beat strength decreases as SPL differences between the two sides of ears increases, if the difference is greater than 2.2 dB. The result suggests that the hearing loss difference between the two sides of ears should be less than 2.2 dB to maximize binaural beating effects.

• The Journal of the Acoustical Society of Korea
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• v.30 no.1
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• pp.49-55
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• 2011

The effects of monaural beating sound generated according to the number of tire pitch blocks to human body are measured from experiments, and the possibilities of similar positive effects of enhancing alpha waves in human brain are investigated. Due to the requirement of repeatability and measurement conditions, recorded sounds of the tire noise are used for the experiment in a quiet room and human responses are measured using HRV. Although the number of statistically meaningful results was small, it showed that positive human reactions are probably possible.