The electrical
voltage generated by a
microphone is very small. Referred to as mic
level, this signal is typically measured in millivolts. Before it can be used for anything serious the signal needs to be amplified, usually to
line level (typically 0.5 - 2V). Being a stronger and more robust signal, line level is the standard signal strength used by audio processing equipment and common domestic equipment such as CD players, tape machines, VCRs,
etc.