mic cap S/N question

[johnferrier]

re: EM172

Max input sound level = 122 dB
self noise = 14 dB
(delta of 108 dB)
Yet, the rated signal to noise ratio is only 80 dB.

What is S/N, if not the difference between max input and the self noise?

Thanks, in advance, for relevant information.

[illconditioned]

re: EM172

Max input sound level = 122 dB
self noise = 14 dB
(delta of 108 dB)
Yet, the rated signal to noise ratio is only 80 dB.

What is S/N, if not the difference between max input and the self noise?

Thanks, in advance, for relevant information.

SNR = 94dB - self noise (dB)

94dB is 1Pa which is the standard sound pressure level used.
Noise is measured in dBA (A weighting of spectrum).

You're right in a sense, if you allow louder sound levels, the effective SNR is increased.  In reality, SNR is the difference between the maximum sound level *you measure* and the self noise of the mic.  So, for quieter sources, your effective SNR will be less than the quoted number.

  Richard

[johnferrier]

SNR = 94dB - self noise (dB)

94dB is 1Pa which is the standard sound pressure level used.

That's what I was missing. Thanks, so much Richard!