intended only to drive other MIDI devices. Percussion controllers such as the Roland Octapad fall into this class, as do a variety of wind controllers and guitar-like controllers such as the SynthAxe. Electronic musical instruments, including synthesizers, samplers, drum machines, and electronic drums, which are used to perform music in real time and are inherently able to transmit a MIDI data stream of the performance. Pitch-to-MIDI converters including guitar/synthesizers analyze a pitch and convert it into a MIDI signal. There are several devices that do this for the human voice and for monophonic instruments such as flutes, for example. Traditional instruments such as drums, acoustic pianos, and accordions which are outfitted with sensors and a computer processor which accepts input from the sensors and transmits real-time performance information as MIDI data. The performance information (e.g., on which notes or drums are struck, and how hard) is then sent to a module or computer which converts the data into sounds (e.g., samples or synthesized sounds). Sequencers, which store and retrieve MIDI data and send the data to MIDI-enabled instruments in order to reproduce a performance. MIDI Machine Control (MMC) devices such as recording equipment, which transmit messages to aid in the synchronization of MIDI-enabled devices. For example, a recorder may have a feature to index a recording by measure and beat. The sequencer that it controls would stay synchronized with it as the recorder's transport controls are pushed and corresponding MIDI messages transmitted. MIDI Show Control (MSC) devices such as show controllers, which transmit messages to aid in the operation and cueing of live theatrical and themed entertainment productions. For example, a variety of show control sub systems such as sound consoles, sound playback controllers, virtual audio matrices and switchers, video playback systems, rigging controllers, pyro and lighting control systems directly respond to MSC commands. However, most standalone generic MSC controllers are intended to actuate a generic computerized show control system that has been carefully programmed to produce the complex desired results that the show demands at each moment of the production. Performance controllers MIDI was designed with keyboards in mind, and any controller that is not a keyboard is considered an "alternative" controller. This was seen as a limitation by composers who were not interested in keyboard-based music, but the standard proved flexible, and MIDI compatibility was introduced to other types of controllers, including guitars, wind instruments and drum machines.