Editing MIDI controller (section)

==Common products==
The most common MIDI controllers encountered are various sizes of MIDI keyboards.  A modern controller lacks internal sound generation, instead acting as a primary or secondary input for a [[synthesizer]], [[digital sampler]] or a computer running a [[VST instrument]] or other software sound generator.  Many have several user-definable knobs and slide controls that can control aspects of a synthesizer's sound in real time.  Such controllers are much cheaper than a full synthesizer and are increasingly equipped with [[Universal Serial Bus]], which allows connection to a computer without a MIDI interface.  Despite not using MIDI directly, software applications recognize such controllers as a ''MIDI device''. In most cases, a USB-equipped controller can draw necessary power from USB connection, and does not require an [[AC adapter]] when connected to a computer.  Keyboards range in size from 88 weighted-action keys to portable 25-key models.