Given that for example I have a -38dB mic such as this one, how can you calculate the gain needed to match the range of the ADC(5v)?
I found this page explaining some basics, and some other questions on this site that give some ballpark numbers but not much background.
From my understanding -38dB=10-38÷20=0.0125V/Pa, which agrees with this calculator.
Now I looked up in some table that normal speech is about 60dB SPL, which would be 1060÷20×0.00002=0.02Pa which corresponds with another calculator.
This would mean a sound of 60dB SPL gives a voltage of 0.0125×0.02=25mV which means you'd need a gain of 4000 to gain even 1V (amplitude, rms, p-p?) and up to 20000 for 5V.
Designs I've googled had gains ranging from 40-1000, with a 200 gain breakout sitting on my desk. Sparkfun sells a board with a gain of 60, while the one by Adafruit goes from 25 to 125. This seem far cry from the 20000 I need according to my calculations to reach a range of 5V. Did I mess up my math somewhere, picked the wrong microphone, or is that just how much I need?