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Mains hum, electric hum, cycle hum, or power line hum is a sound associated with alternating current which is twice the frequency of the mains electricity.The fundamental frequency of this sound is usually double that of fundamental 50/60 Hz, i.e., 100/120 Hz, depending on the local power-line frequency.
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 .
A camera equipped with a synchronous motor transmits a 60/50 Hz signal to the recorder, which is captured as a sine wave pilot tone. This method has since been supplanted by the incorporation of a crystal oscillator within the audio recorder, which generates the 60 Hz signal, in conjunction with a crystal-controlled camera motor.
This is a list of the fundamental frequencies in hertz (cycles per second) of the keys of a modern 88-key standard or 108-key extended piano in twelve-tone equal temperament, with the 49th key, the fifth A (called A 4), tuned to 440 Hz (referred to as A440). [1] [2] Every octave is made of twelve steps called semitones.
60 Hz is a frequency that may refer to: the utility frequency (power line frequency) in the Americas and parts of Asia; the frame rate of video broadcasts in the ...
The frequency range often specified for audio components is between 20 Hz to 20 kHz, which broadly reflects the human hearing range (the highest audible frequency for most people is less than 20 kHz, with 16 kHz being more typical [4]). Components with 'flat' frequency responses are often described as being linear.
In telecommunication, a standard test tone is a pure tone with a standardized level generally used for level alignment of single links and of links in tandem. [1]For standardized test signal levels and frequencies, see MIL-STD-188-100 for United States Department of Defense (DOD) use, and the Code of Federal Regulations Title 47, part 68 for other Government agencies.
The first was a 36 Hz tone from a cooling tower at the local DaimlerChrysler casting plant and the second was a 10 Hz tone from an air compressor intake at the Haynes International plant. [21] After those devices were corrected, however, reports of the hum persisted. [22] Three hums have been linked to mechanical sources.