I could not get Den's circuit to work for some reason with microphone input, so I decided to try to use another circuit I found online. I made some modifications to this circuit and made a schematic:
Using this circuit, I have been able to amplify microphone input and adjust my passband. Currently, this circuit has a high-pass at about 7 Hz and a low-pass at about 23 kHz. I tested the microphone using Audacity, an audio testing program. I produced various sine waves at different frequencies using this program and confirmed that my passband was working as intended. I also used a function generator to ensure that the gain fell off at the cutoff frequencies. Finally, I measured the frequency response of my amplifier circuit:
A text file with the parameters of my frequency response and the raw data is attached as well.
These results are encouraging but I wanted to get some feedback on this new circuit before continuing. This circuit seems to do everything that Den's circuit did but in this case I have a better understanding of the functions of the circuit elements and it is slightly simpler.
# SR785 Measurement - Timestamp: Aug 03 2016 - 18:04:48
#---------- Measurement Setup ------------
# Start frequency (Hz) = 1.000000
# Stop frequency (Hz) = 102400.000000
# Number of frequency points = 800
# Excitation amplitude (mV) = 50.000000
# Settling cycles = 1
# Integration cycles = 5
#---------- Measurement Parameters ----------
# Measurement Group: "Swept Sine" "Swept Sine"