About microphone sensitivity

There are three reason might cause the problems,
1. Lower sensitivity of microphoneThe sensitivity of the condenser microphone is from -36 dB to -48 dB (0dB= 1V/Pa). If we use -44 dB microphones, the sound will be lower.
2. Defective design of amplifierThe impedance for the amplifier will affect the sensitivity and the frequency response.Normally, the higher the impedance is, the better the sensitivity will be. However if the impedance is too high to get enough voltage/current, the high frequency response may get worse.The lower the impedance is, the lower the SPL will be. The too much current will cause the insufficient voltage.Input higher voltage will increase the sensitivity. Depend on the design of the amplifier and the frequency, the sensitivity might increases around 0.3 dB to 0.6 dB by 1 V.3. Defective design of mechanismThe over-length or curved sound receiving holes leads to lower or unnatural sound.