The INSTRUMENT 1 needs to be connected to a sound-generating device: iPhone, iPad, Mac, PC, or USB synth. That device will receive MIDI notes from the INSTRUMENT 1 and translate them into sound data. If the device is USB audio compliant (most of those listed above are), the INSTRUMENT 1 will play sound through its built-in speakers. Optionally, you can choose to plug in headphones or output sound from the connected device itself, bypassing the speakers on the INSTRUMENT 1. The INSTRUMENT 1 is compatible with MIDI-enabled software on Mac and PC, including Ableton Live, Pro Tools, GarageBand, Logic, MainStage, FL Studio, Bitwig, Cubase, and more. Download the INSTRUMENT 1 Editor for Mac and Windows computers to customize your instrument settings when using third-party audio programs.