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Bloop was an ultra-low-frequency, high amplitude underwater sound detected by the U.S. National Oceanic and Atmospheric Administration (NOAA) in 1997. [1]
In acoustics and audio, a transient is a high amplitude, short-duration sound at the beginning of a waveform that occurs in phenomena such as musical sounds, noises or speech. [1] [2] Transients do not necessarily directly depend on the frequency of the tone they initiate. It contains a high degree of non-periodic components and a higher ...
This sound was present when the Pacific Marine Environmental Laboratory began recording its sound surveillance system, SOSUS, in August 1991. It consists of a long train of narrow-band upsweeping sounds of several seconds in duration each. The source level is high enough to be recorded throughout the Pacific.
Frequencies below 20 Hz are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Sound frequencies above 20 kHz are called ultrasonic. Sound propagates as mechanical vibration waves of pressure and displacement, in air or other substances. [5]
A more complex signal also creates more nerve firings and so sounds louder (for the same wave amplitude) than a simpler sound, such as a sine wave. Loudness is perceived as how "loud" or "soft" a sound is and relates to the totalled number of auditory nerve stimulations over short cyclic time periods, most likely over the duration of theta wave ...
Sound intensity, also known as acoustic intensity, is defined as the power carried by sound waves per unit area in a direction perpendicular to that area, also called the sound power density and the sound energy flux density. [2] The SI unit of intensity, which includes sound intensity, is the watt per square meter (W/m 2).
A sonority hierarchy or sonority scale is a hierarchical ranking of speech sounds (or phones).Sonority is loosely defined as the loudness of speech sounds relative to other sounds of the same pitch, length and stress, [1] therefore sonority is often related to rankings for phones to their amplitude. [2]
Amplitude envelope refers to the changes in the amplitude of a sound over time, and is an influential property as it affects perception of timbre. A flat tone has a steady state amplitude that remains constant during time, which is represented by a scalar.