The process of producing a permanent or semipermanent record of sounds that may be used in suitable replay or reproducing apparatus (see reproduction of sound) in order to reproduce the original sounds. Sounds may be recorded in analogue or digital formats, and the three main methods of sound recording are electromechanical sound recording, photosensitive recording (or sound-on-film), and magnetic recording.

Electromechanical sound recording is used to produce gramophone records. The sound to be recorded is detected with one or more suitable microphones and the signals are amplified. The amplified signals are then used to drive a suitable cutter that produces an undulating groove in the surface of a wax or cellulose master disc. The undulations of the groove depend on the magnitude of the signals. In compact disc systems the sound to be recorded is coded using pulse code modulation, and the resulting coded signals are used to cut a series of tiny bumps on the wax or cellulose master disc with a laser. A copper-plated positive mother is usually produced from the master before mass production so that further copies of the master may be made as required.

Photosensitive or sound-on-film recording is used mainly in the cinema or for broadcast entertainment when film is used. The amplified audiosignals are used to modulate a light source, to which the recording film is exposed. The film is then developed and the record appears as a strip of varying density known as the soundtrack. The frequency of the light source is usually such that for convenience a carrier wave is commonly used that is either amplitude-modulated or frequency-modulated by the audiosignal. In white recording, the minimum density of the developed film corresponds to the maximum received power of an amplitude-modulated signal or the lowest received frequency of a frequency-modulated system; the opposite applies for a black recording.

Magnetic recording is widely used for a variety of modern applications. The overall performance is as good as, or better than, the above two systems and it is very convenient in use.