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With a microphone sensitivity of -33dB = 22.4mV/Pa, picking up a conversation (about 60dB SPL), What is the voltage output of the microphone? My concern here is power vs voltage decibel calculations.

60dB SPL is 34dB below 1 Pa. (Treating SPL as power), this is equivalent to 1/(10^3.4) Pa, or 398 microPa, correct?

So then, if I multiply 398 e-6 x .0224 My microphone should produce 8.9 microvolts? Almost -99dBu (-99dBm)?

Which means I would need at least 80dB in front end voltage gain to record this properly?

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If the microphone sensitivity is -33 dbV/Pa then the signal it produces when the pressure is 34 dB lower is -67 dBV or 0.45 mV RMS. Voltages and pressures use "20" in front of the decibel conversion/deconversion formula and not 10.

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  • \$\begingroup\$ THANK YOU. I should have seen that knowing the reference (20 microPa) is -94dB \$\endgroup\$ – Flash Feb 20 '16 at 18:53

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