A microphone, sometimes referred to as a mike or mic, is an acoustic-to-electric transducer or sensor that converts sound into an electrical signal.

(Microphone pre-amplifier) device used to amplify the voltage taken from a microphone to a higher, more usable level. Most microphones must be used in conjunction with a microphone preamp to function properly.

An electronic device for combining ("mixing"), routing, and changing the level, timbre and/or dynamics of audio signals. A mixer can mix analog or digital signals, depending on the type of mixer. The modified signals (voltages or digital samples) are summed to produce the combined output signals.

The process of varying a periodic waveform, i.e. a tone, in order to use that signal to convey a message, in a similar fashion as a musician may modulate the tone from a musical instrument by varying its volume, timing and pitch. Normally a high-frequency sinusoid waveform is used as carrier signal. The three key parameters of a sine wave are its amplitude ("volume"), its phase ("timing") and its frequency ("pitch"), all of which can be modified in accordance with a low frequency information signal to obtain the modulated signal.