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The human range is commonly given as 20 to 20,000 Hz, [3] [4] [note 1] although there is considerable variation between individuals, especially at high frequencies, and a gradual loss of sensitivity to higher frequencies with age is considered normal. Sensitivity also varies with frequency, as shown by equal-loudness contours.
In telephony, the usable voice frequency band ranges from approximately 300 to 3400 Hz. [2] It is for this reason that the ultra low frequency band of the electromagnetic spectrum between 300 and 3000 Hz is also referred to as voice frequency, being the electromagnetic energy that represents acoustic energy at baseband.
The frequencies displayed on the audiogram are octaves, which represent a doubling in frequency (e.g., 250 Hz, 500 Hz, 1000 Hz, wtc). Commonly tested "inter-octave" frequenices (e.g., 3000 Hz) may also be displayed. The intensities displayed on the audiogram appear as linear 10 dBHL steps.
The hearing of older adults is shown to be significantly less sensitive than that of younger adults at frequencies of 4000 and 8000 Hz, corresponding approximately to the piano keys and tones of b′′′′ (B7) and b′′′′′ (B8), respectively. B8 is near the high end of the piano frequency range.
Some non-mel auditory-frequency-scale formulas use the same form but with much lower break frequency, not necessarily mapping to 1000 at 1000 Hz; for example the ERB-rate scale of Glasberg and Moore (1990) uses a break point of 228.8 Hz, [15] and the cochlear frequency–place map of Greenwood (1990) uses 165.3 Hz.
An audio frequency or audible frequency (AF) is a periodic vibration whose frequency is audible to the average human. The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. [1] The generally accepted standard hearing range for humans is 20 to 20,000 Hz.
The morningness–eveningness questionnaire (MEQ) is a self-assessment questionnaire developed by researchers James A. Horne and Olov Östberg in 1976. Its main purpose is to measure whether a person's circadian rhythm (biological clock) produces peak alertness in the morning, in the evening, or in between.
Waking is usually characterized by beta (12–30 Hz) and gamma (25–100 Hz) depending on whether there was a peaceful or stressful activity. [22] The onset of sleep involves slowing down of this frequency to the drowsiness of alpha (8–12 Hz) and finally to theta (4–10 Hz) of Stage 1 NREM sleep. [23]