Microphone Self Noise Test Sequence
A test sequence that measures the self noise of a condenser microphone
The purpose of this sequence is to measure the self noise of a condenser microphone. To do this we use the spectrum analysis step and a power sum calculation to derive an RMS rating for the unit under test.
The sequence has several parts, a few of which are optional. The first section begins by prompting you to enter your mic preamp’s gain. If your preamp does not have a gain setting with labeled detents you may wish to use the ‘Gain & RSP’ sequence located in C:SoundCheck 7.0SequencesElectronics to determine this value. The next part tests the preamp’s self noise so that the system can determine whether or not you have a high enough signal (signal being your microphone’s self noise) to noise ratio to accurately measure your microphone.
The third part of the test takes a measurement from your microphone, creates a spectrum, accounts for the preamp gain, applies an A-weighting, and finally calculates the power sum. The final part of the test prompts you to enter the sensitivity of the microphone if it is known. The resulting display provides you with the equivalent input noise of your preamp, the self noise of your microphone in dBV, and also a result in dB(A) after factoring in the microphone’s sensitivity. You’re also provided with the waveform, a maximum voltage level, and the crest factor to check for sharp transients.