# Keyboard Node

The keyboard node converts MIDI note messages as well as interaction with its on-screen keyboard into pitch and velocity signals.

Pitch is expressed as the fundamental frequency of the note in Hertz. MIDI note velocities are scaled to a zero-to-one range.

The keybaord has two modes:

- Legato. Only one note at a time, and notes will not be re-triggered.
- Poly. Polyphonic - multiple notes can be played simultaneously.

When in poly mode, the keybaord's pitch and velocity outputs become polyphonic, shown as thicker connections. This can consume considerably more CPU time than monophoic processing. To support polyphony efficiently in your patch, use the PolyToMono node, which will mix the polyphonic signals to monophonic.