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The term comes from repetitive phenomena such as sound waves having a frequency measurable as a number of oscillations, or cycles, per second. [ 1 ] With the organization of the International System of Units in 1960, the cycle per second was officially replaced by the hertz , or reciprocal second , "s −1 " or "1/s".
The term speedcore in reference to high tempo hardcore/gabber can be traced as far back as 1995. [7] [8] Disciples Of Annihilation coined the name of the genre with their track "NYC Speedcore". [4] Belgian artist DJ Einrich refined the sound in the late 1990s, using oscillators to transform fast kick drums into notes in octaves. [5]
10 −16: 100 aHz ~137.8 aHz: Once per galactic year (about every 230 million years) 10 −15: 1 femtohertz (fHz) ~3 fHz: Sound waves created by a supermassive black hole in the Perseus cluster [1] 10 −14: 10 fHz ~31.71 fHz: Once every one million years 10 −12: 1 picohertz (pHz) 1.23 pHz Precession of the Earth's axis (about every 25,700 ...
Short: of the order of one second (1 Hz, 60 bpm, 10–100,000 audio cycles). Musical tempo is generally specified in the range 40 to 240 beats per minute. A continuous pulse cannot be perceived as a musical beat if it is faster than 8–10 per second (8–10 Hz, 480–600 bpm) or slower than 1 per 1.5–2 seconds (0.6–0.5 Hz, 40–30 bpm).
However, in the ocean, there is a layer called the 'deep sound channel' or SOFAR channel which can confine sound waves at a particular depth. In the SOFAR channel, the speed of sound is lower than that in the layers above and below.
It can be proven (with the help of a sum-to-product trigonometric identity) that the sum of two unit-amplitude sine waves can be expressed as a carrier wave of frequency f 1 + f 2 / 2 whose amplitude is modulated by an envelope wave of frequency f 1 - f 2 / 2 : [3]
For example, some dog breeds can perceive vibrations up to 60,000 Hz. [7] In many media, such as air, the speed of sound is approximately independent of frequency, so the wavelength of the sound waves (distance between repetitions) is approximately inversely proportional to frequency.
An acoustic wave is a mechanical wave that transmits energy through the movements of atoms and molecules. Acoustic waves transmit through fluids in a longitudinal manner (movement of particles are parallel to the direction of propagation of the wave); in contrast to electromagnetic waves that transmit in transverse manner (movement of particles at a right angle to the direction of propagation ...