Shopping for a Digital Piano
What kind of digital piano should I buy for my piano lessons? I get asked this question often. It is difficult to answer because there is a maze of different makes and models. To address this question, I will highlight three important features of an acoustic piano. Before making a purchase, evaluate how well your choice measures up with regard to these key features. The price range of these instruments is about $1500 to $20,000. The price tag could also be considered a key feature!
Features to Look for in a Digital Piano
A weighted keyboard is a must. The weight provides resistance to key descent. Without weight, it is impossible to control dynamic levels (loud or soft). In addition, weighted keyboards vary in quality and performance. With the lower end models, the mechanism is sluggish and difficult to control. At the higher end, the mechanism is excellent. This superior mechanism results from inserting the workings of an acoustic grand piano into the digital instrument complete with hammers. Referred to as a hybrid piano, there are no strings but there is an array of sensors used to measure hammer velocity. Be mindful that the quality of the sensors makes a difference. Between these two extremes, the mechanisms are usually quite good. Literally, you get what you pay for.
Sympathetic vibration is a key feature that defines the character of the piano. This may not be obvious if you are not familiar with sympathetic vibrations. To demonstrate, do the following. Using an acoustic piano play a low C without making it sound (depress the key slowly). Continue to hold the key down. This opens the string and allows it to vibrate freely. Next, play a C or G higher on the keyboard. The string you are holding open will begin to sound. These are sympathetic vibrations. Digital pianos at the lower end are not capable of producing these vibrations. At the higher end, they have this capability to a varying degree of satisfaction. The success depends on the power of the onboard computer and amount of memory. In addition, the quality of speakers is important.
The damper pedal is an important feature of the piano. In fact, Anton Rubinstein said, "The pedal is the soul of the piano". There are two pedaling techniques referred to as partial and full pedal. Digital pianos at the lower end often do not have a partial pedal capability. Furthermore, be aware that some instruments that do have a partial pedal capability, unfortunately, have shortened pedals. Since the pedal works on the lever principle, shorter pedals offer less control. Therefore, a full-length built-in pedal is the best.
The Grand Hybrid is the most expensive of the digital pianos and is an very fine instrument. The keys of an acoustic piano are connected to hammers which hit strings to make the sound. Similarly, a hybrid piano also has hammers and retains the feel of an acoustic grand piano. However, in place of stings, there is an array of sensors which measures hammer velocity and the sound is produced electronically. Since the sound is purely digital, you can still plug in headphones and get the best of both worlds: the touch of an acoustic piano with the convenience of digital sound.
I don't believe that a digital piano can replace the acoustic instrument. It can, however, serve well as a secondary instrument. Headphones save marriages! Recently, the technology has significantly advanced partly due to the increased availability of affordable computer memory and power.