Key actions, decoded (70 families)

Manufacturers hide their keybeds behind marketing names: GHS, PHA-4, RH III, GrandTouch, GAS-II, TP/40. This decoder resolves every named action in our database into a family - what it is, who builds it, and exactly which models play through it. 592 of 602 models carry a named action; the rest are listed honestly as unnamed.

What actually differs between two actions

The mechanism. Spring actions (synth, semi-weighted, organ) return the key with a spring; hammer actions raise a weighted lever, so resistance grows along the key like on an acoustic piano. Everything else is detail: the mechanism is the difference you feel in the first minute.

Sensors: two or three. A hammer action senses key movement at one or two points; three-sensor designs can detect a key lifted part-way and re-struck, which is what lets fast repeated notes sound clean. Two sensors (Yamaha GHS-class) are fine for learning; three sensors are the dividing line for advancing players.

Escapement (let-off). On a real grand the jack slips out from under the hammer at the end of the stroke - a tiny notch you feel at low volume. Roland (PHA-4 and up), Kawai (RH II and up) and Yamaha (GH3X and up) simulate it; the spec sheets below name which families have it.

Materials and pivot length. The key is a lever: the longer it is behind the visible part, the more control the far end gives your fingers. Plastic keys have short pivots; hybrids add wooden side panels; full wooden-key actions (Kawai Grand Feel, Yamaha GrandTouch with wooden keys) copy the geometry of an acoustic. This is what separates a $1,000 action from a $4,000 one - not the number of sensors.

Keytops. Ivory-feel coatings, matte black keys and waterfall (organ) profiles are comfort features. They change grip and look; they do not change the mechanism.

The RH3 trap: Kawai RH III vs Korg RH3

Two unrelated actions, one confusable name. Kawai RH III (also written RH3) is Kawai's third-generation Responsive Hammer - a plastic hammer action with triple sensors, let-off and counterweights. Korg RH3 stands for Real Weighted Hammer Action 3 - Korg's own graded hammer action built for the SV-2, LP-380, Grandstage, Kronos and Nautilus. They share three characters in the name and nothing else. When a spec sheet says "RH3", the brand in front of it decides what you are actually getting.

How to read the families below

Families are grouped by the brand that builds them - though OEM keybeds travel (Kawai builds one for Nord, Fatar supplies half the industry). Each family lists every model in the database using it, with the price span of those models. Numbers in parentheses after action names (GH3, PHA-4) are generation markers, not sensor counts. 10 models in the database have no published action at all - manufacturers simply do not document it, and we do not guess.