I'm trying to design a preamp for this electret mic.
I kind of pieced this schematic up from something I have found on the web.
Does that look ok? I'm going to sample the output with an ADC (internal in an MCU), and run an FFT on it.
The opamp is a rail to rail op amp, it doesn't have low voltage offset though, should I care about it? The IC has 4 op amps on it, should I add another stage or two and lower each stage's gain ? Or should I use the rest as active filters ?
Do I need any filtering or anything like that?
What is the best way to set the gain?
I was thinking of using a potentiometer for R7.
Here is an ac analysis from LTspice: