Abstract: A device and method are disclosed which perform diagnostics on a microphone and display diagnostic information and instructions to a user. The invention uses a processor to create histograms of the PCM (Pulse Code Modulation) signal after removing any dc bias to determine signal and noise levels and ratios, as well as other parameters. Messages are generated and displayed by the device and method to inform a user that the microphone is working correctly or about possible malfunctions, such as low gain. The messages can advise the user on steps to take to correct the malfunctions, for example, to try a different adapter cable or plug.