Scale dB SPL based on mic sensitivity
You have the known sensitivity of the microphone: 410 mv for a SPL of 114 dB. You also need to know 2 other parameters: 1) the gain between your microphone and the measuring device and 2) the measured voltage. As an example, assume the gain is X10 and the measured voltage is 100 mv. That means that the voltage out of the microphone is 100/10 = 10 mv. Next calculate 10/410 = 0.0244 and convert to dB: 20log(0.0244) = -32 Db. Finally take 114 + (-32) = 82 dB SPL. You should perform the same calculations with your actual data.