Keyboard Expression - Velocity Sensitivity

Velocity Sensitivity

The piano responds to the force with which the keys are initially pressed by changing how hard or fast the hammers strike the strings, which in turn changes the tone and volume of the resulting note or chord; it is velocity sensitive. Several of its predecessors, such as the harpsichord, were not velocity sensitive like the piano. There is some confusion relating to the term pressure sensitive, with some using it as a synonym for velocity sensitive. To avoid this confusion, pressure sensitivity is sometimes called aftertouch. Both velocity and (true) pressure sensitivity are supported independently by the MIDI standard.

In general, only the top of the line electronic keyboards implement true pressure sensitivity, while most professional-quality electronic keyboards support velocity sensitivity. Most inexpensive electronic keyboards, such as toy electronic keyboards and basic learning keyboards made by Casio and Yamaha in the $100 USD price range, do not have velocity sensitivity. Some manufacturers use the term "touch sensitive" (an incorrect term used) in their advertising. Even on a touch-sensitive keyboard, not all digital instrument sounds may incorporate velocity sensitivity into the sound's envelope; for example, the digital pipe organ sound often has no velocity sensitive effects, in imitation of the real instrument. The manufacturers and distributors of some inferior keyboards incorrectly describe their purely velocity sensitive instruments as pressure sensitive.