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Measurement microphone calibration information


In order to take a scientific measurement with a microphone, its precise sensitivity must be known (in volts per pascal). Since this may change over the lifetime of the device, it is necessary to regularly calibrate measurement microphones. This service is offered by some microphone manufacturers and by independent testing laboratories. Microphone calibration by certified laboratories should ultimately be traceable to primary standards a (National) Measurement Institute that is a signatory to International Laboratory Accreditation Cooperation. These could include the National Physical Laboratory in the UK, PTB in Germany, NIST in the USA and the National Measurement Institute, Australia, where the reciprocity calibration (see below) is the internationally recognised means of realising the primary standard. Laboratory standard microphones calibrated using this method are used in-turn to calibrate other microphones using comparison calibration techniques (‘secondary calibration’), referencing the output of the ‘test’ microphone against that of the reference laboratory standard microphone.

A microphone’s sensitivity varies with frequency (as well as with other factors such as environmental conditions) and is therefore normally recorded as several sensitivity values, each for a specific frequency band (see frequency spectrum). A microphone’s sensitivity can also depend on the nature of the sound field it is exposed to. For this reason, microphones are often calibrated in more than one sound field, for example a pressure field and a free field. Depending on their application, measurement microphones must be tested periodically (every year or several months, typically), and after any potentially damaging event, such as being dropped or exposed to sound levels beyond the device’s operational range.

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Measurement microphone calibration

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calibrate measurement microphones. This service is offered by some microphone manufacturers and by independent testing laboratories. Microphone calibration by...

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Calibration

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In measurement technology and metrology, calibration is the comparison of measurement values delivered by a device under test with those of a calibration...

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Pressure measurement

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the conventional units for measurement of diver pressure exposure used in decompression tables and the unit of calibration for pneumofathometers and hyperbaric...

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standard. Measurement microphones calibrated using this method can then be used to calibrate other microphones using comparison calibration techniques...

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Reverberation room

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electrodynamics, such as for measurement microphone calibration, measurement of the sound power of a source, and measurement of the absorption coefficient...

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Plane wave tube

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employed to prevent reflections within the chamber. Test and measurement microphone calibration services are often required to be undertaken at frequencies...

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integrating the pressure gradient between two closely spaced microphones. Pressure-based measurement methods are widely used in anechoic conditions for noise...

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Partial discharge

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against the voltages obtained from a calibration unit discharged into the measuring instrument. The calibration unit is quite simple in operation and...

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quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of real-world...

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Sound level meter

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measurements. It is commonly a hand-held instrument with a microphone. The best type of microphone for sound level meters is the condenser microphone...

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used for acoustic measurement is the microphone. Measurement-grade microphones are different from typical recording-studio microphones because they can...

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applications. Integrated professional accessories Integrated screen calibration tools, screen hoods, signal transmitters; Protective screens. Tablet...

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Real ear measurement

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the microphone (the transmission of sound through this tube was part of the calibration process), which eliminated the need to place the microphone itself...

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Noise dosimeter

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measurement to verify reliable operation. In addition to field calibration routines, the manufacturers recommend periodic comprehensive calibration and...

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measurement IEC 61043 Electroacoustics – Instruments for the measurement of sound intensity – Measurements with pairs of pressure sensing microphones...

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S2CID 22549133. Sutton, C. M. (1990). "Accelerometer Calibration by Dynamic Position Measurement Using Heterodyne Laser Interferometry". Metrologia. 27...

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be very difficult. Control measurements may also be used for other purposes: for example, a measurement of a microphone's background noise in the absence...

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omnidirectional acoustic microphone (O). • Commonly used both in air and underwater. • Can be used in combination with the Offline Calibration Process to measure...

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Audio induction loop

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available in "the back seats of all London taxis, which have a little microphone embedded in the dashboard in front of the driver; at 18,000 post offices...

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DBFS

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of a full-scale sinusoidal signal Digital and Analog Measurement Units for Digital CMOS Microphone Preamplifier ASICs (Analog Devices) - "The definition...

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Sound reinforcement system

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other special test signals. Calibration can be monitored during a performance. Professional audio stores sell microphones, speaker enclosures, monitor...

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Revox B215

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Absolute threshold of hearing

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between 2 kHz and 5 kHz, where the threshold reaches as low as −9 dB SPL. Measurement of the absolute hearing threshold provides some basic information about...

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spring constant and mass are known constants, a measurement of the spring's compression is also a measurement of acceleration. The system is damped to prevent...

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adjustment of a hearing aid is through real ear measurement. Real ear measurements (or probe microphone measurements) are an assessment of the characteristics...

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Nondispersive infrared sensor

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