Who knows about microphones?
I have a question, if the sensitivity of a microphone at a frequency of 1 kHz is 133 mV/N (N stands for force because this microphone converts vibrations into electrical signals, so it is a bone conduction microphone
If you convert this into dB re V/M you get -17.48 re V/N dB. So that is the sensitivity or transmission factor.
What does this sensitivity mean?
why is minus?
And when you calibrate the sound level meter you have to subtract this value -17.48 from the sound level meter values. Why?
(1 votes)
Loading...
-17.48 dBV is equivalent to an effective voltage of 133 mV (rms) – exactly 133.66 mV
L[dBV] = 20 * log10(Urms [V]
0 dBV corresponded to an effective voltage of exactly 1,000V, because this defines dBV, therefore the negative sign at voltages below 1V.
If you now want the relative zero point (0 dB) of a measuring device to be exactly at these 133.55 mV or -17.48 dBV or 1N, you must always take off precisely these -17.48 dB (or just add +148 dB).
So if you were to apply a power of 1 N to this microphone it would release 133 mv? And the sound level knife calculates exactly 0dB at 1 volt?
That’s it. It should be noted, of course, that the force here is not a static force, but a periodically changing force (sinusoidal), which exerts a force of 1N on the sensor as an effective value at 1 kHz.
If your measuring instrument indicates dBV, it displays the 133 mV(rms) emitted by the microphone as said -17.48 dBV.