High gain microphone pre amplifier circuit, where would the bottlenecks be?

[Plecto]

So what about the microphone itself? I'm thinking that something in my circuit is filtering out high frequencies since it goes off easily by a weak hum, but flicking my fingers doesn't (even though the flicking is fare more audible). I know that the human ear is far more sensitive to frequencies in the 3khz region, but still. The only low-pass filter I can find is the GBP, but with a gain of 300, the cut-off should be about 20khz. The mic I'm using now has a 20-15khz response, I could at least get one with a 20khz response. I'm looking at mics at mouser's website, but there's an ocean of them and I'm not sure what to look for. Is the S/N ratio parameter something to take into consideration for this application perhaps? I don't know much about these electret mics and their parameters

 

[Audioguru]

Since the opamp is wrongly made inverting with a low input resistance of only 1k ohms then its gain is 300 only when fed from a source with a very low resistance. But an electret mic is not a low resistance, it is about 2.5k ohms which in series with the 1k input in your circuit causes a 300k to 3.5k divider which produces a gain of 86.

C7 cuts high frequencies and if the diode is a 60Hz rectifier then it might also cut high frequencies. All the very cheap electret mics I have seen produce excellent high frequency response and low noise.
Here is the frequency response graph of an ordinary electret mic:

 

[Plecto]

C7 is not present.

I see now how the gain is reduced by my design But wouldn't increasing the feedback resistor to 1M do the same trick as using a non-inverting design, gain wise I mean?

 

[Audioguru]

When the feedback resistor is 1M then some stray capacitance of only 20pF cuts frequencies of 8kHz and up.
Use the inverting opamp circuit with a 600 ohms dynamic mic (coil and magnet) but use a non-inverting opamp circuit for an electret mic.