![]() The Journal of the Acoustical Society of America. Bei 120 dB erreicht der Schalldruck eine Stärke, die wir als unangenehm oder sogar schmerzhaft empfinden. Als logarithmische Skala ist die dB-Skala dafür geeignet, den für Menschen hörbaren Schalldruckbereich darzustellen. Dezibel ist eine Hilfsmaßeinheit zur Angabe des Schalldrucks. It is named after the famous Alexander Graham Bell, who is known for inventing the telephone. "A comparison of two different sound intensity measurement principles" (PDF). Das Wichtigste zu Dezibel zusammengefasst. A dB or decibel is a measuring unit that evaluates the relative power or intensity of sound, generally in contrast with a reference point. Its a logarithmic scale, so a sound 10 times more powerful is 10 dB. ^ a b c Jacobsen, Finn de Bree, Hans-Elias (). The Decibel Scale On the decibel scale, the smallest audible sound (near total silence) is 0 dB.Fundamentals of general linear acoustics. ^ Sound Power Measurements, Hewlett Packard Application Note 1230, 1992.The ISO Standard 80000-3:2006 sets out the following quantities. One decibel 1/10th of one bel (hence the name ‘Deci’), named in honour of Alexander Graham Bell. sec 8.7, "Logarithmic quantities and units: level, neper, bel", Guide for the Use of the International System of Units (SI) 2008 Edition, NIST Special Publication 811, 2nd printing (November 2008), SP811 PDF The first use of the decibel scale was for the measurement of power in the telephony of the early 20th century in the Bell System in the United States. ^ Ross Roeser, Michael Valente, Audiology: Diagnosis (Thieme 2007), p.3.0, International Electrotechnical Commission, 19 July 2002. ^ "Letter symbols to be used in electrical technology – Part 3: Logarithmic and related quantities, and their units", IEC 60027-3 Ed.Compared to pressure-based probes, p-u intensity probes are unaffected by the pressure-to-intensity index, enabling the estimation of propagating acoustic energy in unfavorable testing environments provided that the distance to the sound source is sufficient. The “reactivity” (the ratio of the reactive to the active intensity) indicates whether this source of error is of concern or not. Therefore, the phase calibration is critical when measurements are carried out under near field conditions, but not so relevant if the measurements are performed out in the far field. For example, by falling 6 decibels, you shift 3 dB first, and another 3 dB. This essentially indicates that you are adding or falling 50 percent of the residual sound pressure thresholds to your sensitivity with every 3 decibels you step up or down the scale from 0-194. It is also possible to have negative sound levels: - 20. The scale of decibels is logarithmic, not linear. So 0 dB does not mean no sound, it means a sound level where the sound pressure is equal to that of the reference level. is the p-u phase mismatch introduced by calibration errors. 0 dB occurs when you take the log of a ratio of 1 (log 1 0). I 0 = p 0 2 I p 2 = p 0 2 p c p 2 = p 0 2 z 0. ![]()
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