The technical index of mike is choice and the important basis of use mike. Understood it cuts a meaning really only, ability is in the distance of buy mike and acoustical source reasonably, master its sound to control the changeover concern with voltage, be in mike well and truly conversion becomes the sound pressure level of sound field the n that sound console input carries, define the input gain of sound console thereby, receive highest letter the linear signal with comparing of a confusion of voices, lack fidelity lowest.
So closely related the input of the what index of mike and sound console? Where is the working n of the affirmatory sound console that how occupies at the same time?
One, the meaning of a few main index
The technical index of broadcast class mike has nearly 10, to acoustical source and sound console, the most important is the following 3: Sound pressure level of the biggest input, sensitivity and n of the biggest output. Sound pressure level of the biggest input is mike can the tolerance that susceptive achieves 0.5 total harmonic to break the biggest really sound pressure level, the relation definition that it and sound press is:
0dB SPL=2x10-5Pa
The sound pressure level of the biggest input of professional mike is decided higher commonly, want it only the space between harmonic source is suitable, won't arise what can hear is lack fidelity. Because we discuss mainly here,affect n of sound console job directly hind two kinds of index.
1.Sensitivity
Sensitivity is mike approachs voltage of the output below drive and the specific value that input acoustical pressing in unit sound, its unit is MV/Pa. To agree with the magnanimity of the n in circuit, sensitivity is OK also decibel value expresses. Inchoate decibel expresses with unit DBm and DBV more:
0dBm=1mW/Pa, the 1mW power that loses 1Pa to issue 600 Ω load to bring into acoustical pressing namely outputs a definition to be 0dB;
0dBV=1V/ μ Bar, output the 1V voltage that presses next generation in sound of input of 1 μ Bar the definition is 0dB.
Present decibel expresses with unit DB μ :
0dB μ =0.775V/Pa, be about to 1Pa input sound presses next mike 0.775V voltage to output a definition to be 0dB (to press mike sound so, the n magnanimity after voltage is changed, the uses generally 0dB μ in integrating circuit = 0.775V) of this one referenced unit.
Apparent, no matter how does sensitivity express, we can change it the μ that it is DB, premise is travel input unites Pa this unit.
For example: The sensitivity of NEUMANN U89 mike is 8mV/Pa, but direct by
20lg[(0.008V/Pa)/(0.775V/Pa) ]
Reach its sensitivity is about - 40dB μ .
Be like again: The sensitivity of AKG C414 mike is - 60dBV, by
0dBV=1V/ μ Bar=10V/Pa
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