analog recording:

The norm since the introduction of recording in the nineteenth century. Transforms the energy of sound waves into physical imprints (as in pre-1925 acoustic recordings) or into electronic waveforms that closely follow (and can be used to reproduce) the shape of the sound waves themselves.

digital recording:

Samples the sound waves and breaks them down into a stream of numbers (0s and 1s). A device called an analog-to-digital converter does the conversion. To play back the music, the stream of numbers is converted back to an analog wave by a digital-to-analog converter (DAC). The analog wave produced by the DAC is amplified and fed to speakers to produce the sound.

drum machines:

Drum machines such as the Roland TR 808 and the Linn LM-1—almost ubiquitous on 1980s dance music and rap recordings—rely on “drum pads,” which performers strike and activate, triggering the production of sampled sounds.

Musical Instrument Digital Interface (MIDI):

Device that standardized digital technologies, enabling devices produced by different manufacturers to “communicate” with one another.

sequencer:

Device that records musical data rather than musical sound and enables the creation of repeated sound sequences (loops), the manipulation of rhythmic grooves, and the transmission of recorded data from one program or device to another.

synthesizer:

Device that enables musicians to create or “synthesize” musical sounds. Began to appear on rock records during the early 1970s.