Designing a Microphone Circuit for 30-100dB Range Using EM4015LW-38C10NF & LM386

Hi,
I am trying to design a microphone circuit that can detect voice and convert the voltages coming out of the mic to dB. The main goal here is to capture noises as low as 30dB and as high as 100 maybe. I have tried couple circuits but even with high amplification I couldn't get what I wanted. Is there any advice or approaches on how to build this?
I used

microphone: https://www.digikey.ca/product-detail/en/soberton-inc/EM4015LW-38C10NF/433-1155-ND/7069647



opamp: LM386


thanks

If you want a readout in dB you will have to convert the input signal to a voltage representing the dB value of the sound - this is a logarithmic function, as you may know dBs are a ratio, for voltage this isDb = 20 Log V1/V2
for measurement purposes V2 corresponds to a certain signal level (often 1 mW, giving a figure in dBm) or a certain sound pressure level (which will give you dBA (A = Acoustic)To convert the signal to a voltage proportional to dB you should use one of the many RMS to dB converter ICs that do this, one of the best known is the Analog Devices AD736. You can then use either an analogue or a digital voltmeter to display your value.This is not a simple task - you will probably have to use a preamp to get your signal to a usable level for the converter IC, and also incorporate a preset adjustment to calibrate your meter.  You may have to organise one or more ranges to cover the range of values you want. You might have to borrow a commercial Sound Pressure meter for the calibration.  But it is definitely do-able.  Good luck with it.

One more comment.  You note you're using the LM386 as an op-amp.  The LM 386 is a low power (~1W) audio amplifier (for driving small speakers) and not at all the sort of thing you would use to amplify a microphone.  You should ideally use a low noise op-amp, something like an NE 5534, though there are doubtless better and more modern ones.  A lot will depend on whether you are using a single supply or dual supply - for single supply the LM358 is good, though not specifically low noise.