The percussion controller is an electronic device that uses the Musical Instrument Digital Interface (MIDI) protocol to generate rhythms using virtual music software and instruments in conjunction with either computers or physical musical instruments, such as synthesizers or electronic drum sets. The controller sends MIDI event messages containing information about tempo, pitch, volume, and other parameters to the devices that will actually create the rhythm sounds. The percussion controller can also be used to create rhythms on conventional percussion instruments, such as acoustic drum sets, cymbals, and hand drums that are equipped with electronic triggers. Due to the wide range of applications and settings in which MIDI-generated rhythms can be used, percussion controllers are available in a variety of different forms and vary considerably in their capabilities.
The most basic percussion controllers usually include a set of rubber pads that can be played with either drum sticks or one's hands and fingers. Aside from generating these rhythm sounds internally, which can then be transmitted directly to an audio system, it may also be capable of triggering rhythm patterns on external devices fitted with triggers. The controller usually contains some preset rhythms that can be modified by the user, as well as memory storage for user-created rhythms. The percussion controller is also usually equipped with a sound effect generator with which to modify the sound by applying effects such as reverb and flanging. Some controllers include a pattern sequencer permitting the musician to create and store lengthy rhythm tracks for playback in synchronization with other music elements.
The more sophisticated percussion controller usually offers an input with which the percussionist can add previously-recorded rhythm loops and samples. These rhythm tracks may be loaded into the percussion controller either using a memory card, USB port, or MIDI jack. Once imported, these loops and samples can be integrated and synchronized with other rhythm instruments and tracks to create rhythmically-complex music. Controllers are also usually equipped with a number of pre-installed sounds or "voices." These run the gamut from traditional Western drum and percussion sounds to exotic Asian and African instruments.
Similarly, most modern synthesizers and electronic keyboards contain a percussion controller with which to create rhythmic accompaniments. Non-percussionists may prefer creating rhythm sequences this way, whereas drummers will likely opt for an electronic drum kit that consists of drum and cymbal pads that can be played using conventional drumming techniques. Another option for drummers is to retrofit a traditional acoustic drum kit with a controller plus drum and cymbal triggers. While the controller generates MIDI-created sounds, the drummer adds in his or her own rhythmic accompaniment. Using a combination of controller-triggered rhythm patterns plus live, acoustic sounds, the drummer can create rhythmic effects that would be impossible using traditional percussion instruments alone.