Evaluating Touch

Aside from sound, the most important element in the selection of an instrument is likely to be the feel of the action. Unless you're considering only digital pianos that employ an actual acoustic action (a "hybrid" piano"), you'll be selecting from a variety of actions that all try to emulate the feel of an acoustic action. As in an acoustic piano, the action of most digital pianos is primarily an arrangement of levers, but the digital action is far less complex and doesn't require regular adjustment. Players use a few definable criteria to judge an action. Some are easily measured, others are largely subjective. Among the most frequently debated by digital piano buyers is touch weight.

Touch weight is the amount of force, typically measured in grams, required to depress a key. A touch weight in the range of 50 to 55 grams is generally considered normal for an acoustic piano. The resistance offered by the key is a combination of friction and the mass of the parts being moved. Both of these factors behave slightly differently in acoustic pianos than in digital pianos.

Just as there is no single correct piano sound, there is no single correct touch weight; rather, there is a range of acceptable touch weights. If you spend the majority of your playing time with a heavy action, when you encounter an instrument with a lighter action, be it acoustic or digital, you'll play too heavily—and vice versa. The only cure is to play as many instruments as possible, as often as possible. Listen to how each piano responds and adjust your touch accordingly. You've probably driven cars with light steering and cars with heavy steering, and generally managed to avoid hitting any trees with either of them. With varied experience, you learn to adapt.

Yet another aspect of touch weight is that it varies from one end of the keyboard to the other. In an acoustic piano, the hammers are significantly heavier at the bass end of the keyboard than at the treble end, which results in heavier touch weight in the bass and lighter touch weight in the treble. Enter the graded hammer action: To replicate the touch weight of the acoustic piano keyboard, most digital piano actions employ in their designs the equivalent of graduated hammer weights. Rather than using 88 different weights across the span of the keyboard, which would be cost-prohibitive and of questionable value, it's common to use four different touch-weight values, each one used uniformly throughout one touch-weight zone.

88-Note Weighted Keyboard

Even entry-level digitals should feel much like an acoustic piano. If you have some playing experience, you'll want to try two or three competing models to see what feels best to you. None of the available models has an overly heavy touch. So-called semi-weighted keyboards, which depend on springs for their weight, should be avoided, as they don't feel enough like an acoustic piano. Is a keyboard with fewer than 88 notes a viable alternative? In a word, no. None has a decently weighted keyboard. In addition, students who use instruments with short keyboards tend to outgrow them quickly, and suffer some degree of disorientation when taking lessons on an 88-note keyboard.

For those of you interested in a more detailed discussion of touch, please refer to "Digital Piano Basics, Parts 1: Imitating the Acoustic Piano" in Acoustic & Digital Piano Buyer. Additional topics covered there include:

  • Differences in Key Design
  • Dynamic (Velocity) Sensors
  • Pedal Functions

Introduction to Buying
a Digital Piano

by Alden Skinner

Acoustic & Digital
Piano Buyer