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Further research into crackling noise was done in the late 1940s by Charles Francis Richter and Beno Gutenberg who examined earthquakes analytically. Before the invention of the well-known Richter scale, the Mercalli intensity scale was used; this is a subjective measurement of how damaging an earthquake was to property, i.e. II would be small vibrations and objects moving, while XII would be ...
Audio restoration is the process of removing imperfections (such as hiss, impulse noise, crackle, wow and flutter, background noise, and mains hum) from sound recordings. Audio restoration can be performed directly on the recording medium (for example, washing a gramophone record with a cleansing solution), or on a digital representation of the ...
Signal-to-noise ratio (SNR), however, is the ratio between the noise floor and an arbitrary reference level or alignment level. In "professional" recording equipment, this reference level is usually +4 dBu (IEC 60268-17), though sometimes 0 dBu (UK and Europe – EBU standard Alignment level).
Fine crackles are soft, high-pitched, and very brief. This sound can be simulated by rolling a strand of hair between one's fingers near the ears or by moistening one's thumb and index finger and separating them near the ears. Their presence usually indicates an interstitial process, such as pulmonary fibrosis or congestive heart failure.
Upsweep is an unidentified sound detected on the American NOAA's equatorial autonomous hydrophone arrays. 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.
Respiratory sounds, also known as lung sounds or breath sounds, are the specific sounds generated by the movement of air through the respiratory system. [1] These may be easily audible or identified through auscultation of the respiratory system through the lung fields with a stethoscope as well as from the spectral characteristics of lung sounds. [2]
This makes a crackling sound, which has been compared to candy being unwrapped, Rice Krispies, or the sound of a log fire. This sound, first discovered by German physicist Heinrich Barkhausen, is called Barkhausen noise. Similar effects can be observed by applying only mechanical stresses (e.g. bending) to the material placed in the detecting coil.
Those who test and evaluate equipment can be roughly divided into two groups: "Objectivists", who believe that all perceivable differences in audio equipment can be explained scientifically through measurement and double-blind listening tests; and the "Subjectivists", who believe that the human ear is capable of hearing details and differences ...