Signal-to-Noise Ratio (S/N or SNR)

The ratio of the maximum signal that a system can record or reproduce to the inherent noise of that system. For digital systems, it is usually defined as the ratio between RMS value of the maximum recordable sine wave and the RMS value of the quantization noise. In microphones, it has been common to describe the S/N by the ratio given by the sensitivity (= microphones’ output when in sound pressure of 1 Pa, which is the same as 94 dB SPL) to the equivalent level of the microphones’ self-noise. Example: For DPA4060, the equivalent A-weighted self-noise level is 23 dB. Thus the S/N ratio is 94 - 23 dB = 71 dB. The S/N can no longer be found in DPA microphone specs as it is removed from the standard IEC 60.268-4 Sound System Equipment – part 4: Microphones.