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I is the sound intensity; I 0 is the reference sound intensity; 1 Np = 1 is the neper; 1 B = 1 / 2 ln(10) is the bel; 1 dB = 1 / 20 ln(10) is the decibel. The commonly used reference sound intensity in air is [5] = /. being approximately the lowest sound intensity hearable by an undamaged human ear under room conditions.
The use of sound intensity rather than sound pressure to determine sound power means that measurements can be made in situ, with steady background noise and in the near field of machines. The sound power is the average normal intensity over a surface enclosing the source, multiplied by the surface area. [1]
Dynamic range is a measure of how small you can measure a signal relative to the maximum input signal the device can measure. Expressed in decibels, the dynamic range is 20 log (Vmax/Vmin). For example, a device with an input range of ±10 V and a dynamic range of 110 dB will be able to measure a signal as small as 10 μV.
In a sound wave, the complementary variable to sound pressure is the particle velocity. Together, they determine the sound intensity of the wave. Sound intensity, denoted I and measured in W·m −2 in SI units, is defined by =, where p is the sound pressure, v is the particle velocity.
Sound waves are often simplified to a description in terms of sinusoidal plane waves, which are characterized by these generic properties: Frequency, or its inverse, wavelength; Amplitude, sound pressure or Intensity; Speed of sound; Direction; Sound that is perceptible by humans has frequencies from about 20 Hz to 20,000 Hz.
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 ...
Auditory sensitivity changes when the duration of a sound becomes less than 1 second. The threshold intensity decreases by about 10 dB when the duration of a tone burst is increased from 20 to 200 ms. For example, suppose that the quietest sound a subject can hear is 16 dB SPL if the sound is presented at a duration of 200 ms.
Sound energy; Sound energy density; Sound exposure; Sound intensity; Template:Sound Level Label Examples; Sound level meter; Sound limiter; Sound power; Sound pressure; Speech interference level; Speed of sound; Stress wave tomography