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How do I find microphone output voltage?

Discussion in 'Electronic Basics' started by [email protected], Mar 8, 2007.

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  1. Guest


    How can I calculate the output level of a microphone,
    I assume it is found from the Sensitivity , but how?
    For example, I want to know what voltage I will
    get if the SPL is 60dBA (on the sound level meter)

    For example, I find in the datasheet Sensitivity = -40dB
    Assuming this is actually dBV, then it should be 10mV
    (1Volt/100), but at what SPL is that taken?

    Thank in advance
  2. Guest

    The mic preamps I've used in the past with dynamics, electrets and
    condensers ran 40 - 60 dB of gain. With my AKG C451s 46 dB is a good
    level that covers the bulk of uage with no fiddling around. I know you
    want to calculate the actual value but you just KNOW as soon as you
    get it working you'll adjust the level anyway.

  3. Phil Allison

    Phil Allison Guest

    ** The data sheet should tell you - but the usual reference
    pressure level these days is 10 microbars ( ub) or
    1 Pascal(Pa) .

    A "microbar " is one millionth of atmospheric pressure and
    equates to 74 dB SPL.

    So, 10 ub = 94 dB SPL.

    ........ Phil
  4. Eeyore

    Eeyore Guest

    A proper sensitivity spec will state the measurement SPL ( usually in

    What is it more generally you're concerned about ?

  5. Eeyore

    Eeyore Guest

    Decent mic preamps have adjustable gain. It's essential when working with stuff
    from close miking to recording wildlife.

    80dB of gain range is not unknown and 50dB is routine.

  6. Guest

    So if an electret mic is quoted as Sensitivity = -60dB
    then this means at 74dBA I will measure 1mV and at
    134dBA I will measure 1V ?
  7. Phil Allison

    Phil Allison Guest

    ** No.

    The reference SPL level is 94 dB in most cases these days.

    134 dB SPL may well be beyond the ability of a budget electret mic.

    ......... Phil
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