Hammer Action Keyboard for Digital and Acoustic Pianos

Hammer action made dynamic piano playing possible for the first time. Invented in the 18th century by the Italian instrument maker Bartolomeo Cristofori, the hammer action keyboard was continuously enhanced. It created the piano touch that we know from today’s concert grand pianos – and also expect from digital pianos.

Electric Piano vs. Upright Piano

Of course, the differences between a real grand piano and the hammer action keyboard of a digital piano are enormous. On the one hand, the principle of a hammer moved by the key always remains the same. On the other hand, the primary function of a hammer action keyboard on a digital piano is to simulate the action of a real piano, not to generate sound.

Pianoforte – playing the piano with velocity sensitivity

With the invention of the hammer action by the Italian Bartolomeo Cristofori, the pianoforte became an instrument in its own right. The name itself refers to the expressive possibilities of playing at different velocities – from piano to forte. Before that, harpsichord variants dominated the world of keyboard instruments. These include the cembalo and harpsichord itself, none of which allow the continuosly dynamic play of the notes. One exception was the clavichord, which allowed pressure-sensitive play. In terms of mechanics, it was already more similar to the fortepiano, as here tangents struck the strings.

How does hammer action work?

The development of the hammer action has gone through several stages, culminating in the modern double escapement action. This is an evolution of the first double escapement action developed by the Frenchman Sébastién Érard in the 1820s.

The double-escapement mechanism is a complex construction in which the key does not directly move the hammer: First, the wippen moves upwards, so the jack collides with the hammer shank, flinging the hammer upwards. Another advantage of the mechanical decoupling of key and hammer movement is that the hammer can fall back after striking the string and is immediately ready for another strike.

Hammer action keyboard on digital pianos

The hammer action keyboard of a digital piano differs significantly from those of acoustic instruments. For this reason, beginners often ask if they can practice or learn how to play dynamically on a digital piano. Electronic or optical sensor systems trigger the sound on a digital piano and transmit the keyboard expression to the sound generator.

However, the hammer action itself is not involved in the sound generation process. The primary function of the hammer action keyboard on a digital piano is to reproduce the authentic feel of an acoustic piano. As such, it is an important feature of a digital piano.

How to recognize a good hammer action keyboard

You can find a hammer-action keyboard even on entry-level models in the lower price range. However, it is worth taking a closer look at the features – brands generally offer the best quality: Casio, Dexibell, GEWA, Kawai, Korg, Nord, Roland, Studiologic and Yamaha.

Keyboards come with different equipment depending on the price or model class. As a beginner, it doesn’t have to be the absolute best keyboard. It anyway takes a certain amount of time and playing experience to get a feel for the differences. If you are looking for the most authentic “piano feel” possible, look for the following keyboard features:

• Hammer action
• triple sensor system
• Graduated or scaled weighting (graded hammer action)
• Counterweight ( used to balance key and hammer weights)
• Let-off mechanism (escapement, let-off)
• Synthetic key tops (ivory-feel keyboard)

Hammer action and keyboard on hybrid digital pianos

In principle, the hammer action of a hybrid digital piano is very similar to that of an acoustic piano. An exception is the Alpha Studio Piano, equipped with a real Renner piano action. Here, the action and keyboard are exactly the same as on an acoustic grand piano: instead of striking a string, the hammerheads strike an electronic element that both triggers the sound and measures the velocity. This unique system, developed by the manufacturer Alpha Piano, allows extremely high-resolution velocity control.

Space-saving design

The hammer action keyboards of conventional digital pianos come in a space-saving design: A movable weight is added to each key, which simulates the hammer movement and string attack. Here, too, you will find designs of varying complexity: The more expensive the digital piano, the more complex the hammer action keyboard.

The only stage piano that is on par with a hybrid digital piano in terms of keyboard is the Kawai MP11 SE. This also explains why the body shape is slightly higher than that of conventional stage pianos. The Kawai MP11 SE has a complete wooden-key keyboard and grand piano-like hammer action. As a result, no other stage piano offers a better playing feel.

Small differences make a big difference in feel

Good hammer action keyboards are equipped with a let-off mechanism and counterweights that allow even finer touch control. Kawai already uses such keyboards in their mid-range instruments. For example, the Kawai Responsive Hammer III (RH III) keyboard makes the CN-201 and CN-301 models attractive entry-level digital pianos.

You can see the influence of the “counterweight” detail in the Yamaha Clavinova series: the Yamaha CLP-775 and Yamaha CLP-785 models have the same high-quality Grand Touch keyboard, but there is a clear difference in playing feel. As the top model, the CLP-785 features this improvement, the keyboard feels even more comfortable.

It is always worth keeping an eye on the manufacturer’s price range, since most digital piano series have a “mid-range level”. Here you can find successive instruments that differ in terms of the cabinet, speaker equipment, and additional functions, while the keyboard and hammer action are identical. For example, Yamaha CLP-735 and CLP-725 (GrandTouch STM), Kawai CA-901 and CA-701 (Grand Feel III action with wooden keys), Casio GP-510 and GP-310 (hybrid action with wooden keys).

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