You may have decided to purchase a digital piano instead of an acoustic piano for many reasons, such as availability of multiple tones, headphone playing capability, lower price, etc. But before you get one, make sure you like the feel of the keyboard action. This is how the keys feel when being played. It all has to do with what kind of weighted keys the keyboard uses.
If you want the feel of an acoustic piano, you will want a weighted keyboard. Many digital pianos will emulate the feel of an acoustic piano by using keyboard weighted keys. They can do this in multiple ways. Before we look at some of the different keyboard weighted types, let's get a quick understanding of how an acoustic piano gets its "feel"
An acoustic piano uses a hammer striking mechanism. When you press the keyboard keys it presses a lever. The lever causes a hammer to strike the strings. The hammer then bounces off the string. The key returns to the resting position by the weight of the hammer and levers. It's very natural feeling with no springs. It just uses the weight of the hammer and the momentum from bouncing off the string.
This type of feel is what digital pianos try to recreate. So let's look at the three types of keyboard actions.
Non-Weighted Keys
Non-weighted keys are very light feeling. They are what organs and synthesizers use. Obviously, they do not have the heavy, weighted feel that you get from an acoustic piano. Since there is little weight and no hammers using momentum from bouncing off a string, these non-weighted keyboards must use springs to bring the keys back to the resting position. The upside to this is that the keys are easier to press allowing quick movement over the keyboard. The downside is this feels nothing like an acoustic piano. Also, when keys so easily press down it is easier for your finger to barely graze a key that you had no intention of playing, making a noticeable mistake in your performance.
Weighted Keys
These keys have a weight in them to give them some substance. The weight makes them harder to press down, just like you'd expect on an acoustic piano. They come close to feeling like an acoustic piano. However, they do not have any type of hammer mechanism in them, so in that aspect they will not feel like an acoustic piano. The good news is that for a cheaper price this type of weighted keyboard comes close to approximating the feel of an acoustic piano. The bad news is that you will always be lacking that "momentum" feel on the keys of an acoustic when the momentum of the hammer bouncing off the string plays a part in bringing the keys back to a resting position.
Weighted Hammer Action Keys
These types of weighted keys come the closest to emulating the feel of an acoustic piano. Keyboards with this feature use a hammer simulating mechanism to give you the feel of a moving hammer. Some digital pianos even use actual hammers, not just a simulating mechanism. The big one that comes to mind is Kawai's AHAIV keyboard action. With these weighted keys you not only get the weight and resistance on the keys, but you also get the feel of a hammer's momentum. Both features you get on an acoustic piano keyboard.
Other Keyboard Descriptions
Before you buy a digital piano, you will come across other phrases that describe the keyboard action. The most common one will be Weighted Scaled Hammer Action. So what does the word "Scaled" mean? It means that the keys emulate the feel of an acoustic grand piano by being heavier on the lower notes and lighter on the higher notes.
On an acoustic grand piano, the lower notes are a little harder to press than the higher notes. So to emulate that feel, digital piano manufacturers will make their lower notes heavier. Other phrases you will see that describe this same thing are "Graded Hammer Action" and "Progressive Hammer Action." Also, look for the phrase "weight gradation" to indicate keys are heavier in the lower end and lighter in the high end.
Conclusion
Each manufacturer of digital pianos seeks to make their keyboard feel as close to an acoustic piano as possible. They will each do it in a different way based on their technologies and patents. Every piano player will have their opinion about which digital piano feels "the best." If you want the feel of an acoustic piano you now know to narrow your list of digital pianos to those with weighted hammer action. But the only way to find out if you like the feel of a particular digital piano is to play it.
