A music sequencer is a device or application software that can record, edit, or play back music, by handling note and performance information in several forms, typically CV/Gate, MIDI, or Open Sound Control, and possibly audio and automation data for digital audio workstations (DAWs) and plug-ins.
1980s typical software sequencer platform, using Atari Mega ST computer
User interface on Steinberg Cubase 6, a digital audio workstation with an integrated software sequencer
An analog sequencer
A step rhythm sequencer on the drum machine
CV/gate is an analog method of controlling synthesizers, drum machines, and similar equipment with external sequencers. The control voltage typically controls pitch and the gate signal controls note on-off.
The CV/gate interfaces of a Korg ARP analogue synthesiser