Nord User Forum

What is the Nord Stage 4 "Triple Sensor" feature? I can't find anything online.

If you use the search here you can find it... it is anyway related to the keybed, which was already like that (i.e. with triple contact) on NP5 btw.

Triple sensor Keybeds are not unique to Nord. Many mid to high end digital pianos have triple sensors. Basically, a dual sensor KB has a sensor at the beginning of a key press and near the end of a key press. Thus it can determine key velocity but essentially requires the key to be completely (or nearly completely) released before it can reset for a repeat key stroke.
Acoustic grand pianos for the past 200 years or so have included a mechanical repetition mechanism. A grand piano key does not need to be fully released to re-strike a note. In an attempt to make a digital piano action more similar to a grand piano, manufacturers have added a third sensor to the key action that can sense the movement of the keystroke between the standard two sensors and well before it is fully reset which allows the Key to repeat faster.
Having said all that, having a triple sensor is just one attribute of the action that makes it more or less piano like.

To find more information, you might want to search 'double escapement' which is the name for a grand's key stroke mechanism. What is special with the notes played in fast repetition is that there is no damping in between - they always sustain. That's something a digital piano will need to replicate, too.