The perception of sound in any organism is limited to a certain range of frequencies. For humans, hearing is normally limited to frequencies between about 20 Hz and 20,000 Hz (20 kHz), although these limits are not definite. The upper limit generally decreases with age.
A sound with a very high frequency (17,4 kHz) can generally be heard only by young people.
The sound can typically only be heard by people below 25 years of age, as the ability to hear high frequencies deteriorates in humans with age.
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| 熱門國家 | 系統支援 | 版本 | 費用 | APP評分 | 上架日期 | 更新日期 |
|---|---|---|---|---|---|---|
| 美國 (U.S.A) | Windows Windows 市集 | 1.0.0.0 App下載 | 免費 | 2011-10-14 | 2014-09-26 |
