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Anatomy of a Disklavier

by George F. Litterst

The Disklavier is—first and foremost—an acoustic piano. Like any piano, it has 88 keys, hammers, strings, pin block, soundboard, three pedals, and thousands of moving and stationary parts. When played by a pianist, the instrument behaves in the same way as any other piano.

Pedals and KeysOutwardly, the typical Disklavier looks similar to a traditional Yamaha piano of the same size, with the visual differences primarily being a control unit, a box that encloses the pedal solenoids on a Disklavier grand, and the electrical cable that plugs into the wall. Hidden inside the piano is a remarkable array of sensors, solenoids, and a few circuit boards, none of which affect the touch or tone of the instrument in any way. In some cases there is also a mute rail that enables the Silent system.

The Disklavier-specific components of the instrument provide the ability to:

(1) record and play back performances, complete with moving keys and pedals.
(2) connect to computers, tablets, and other MIDI devices.
(3) connect to the Internet in order to receive streaming performances from DisklavierRadio™ and DisklavierTV™.

In many cases, there is also a Silent feature that prevents the hammers from hitting the strings, thus making it possible to play the piano and listen using headphones.

Types of Disklavier
The Disklavier made its debut in the United States in 1987. Since that time, Yamaha has manufactured many Disklavier models that can be categorized as follows:

(1) Playback-only Models
These have typically been small grand pianos that lack the record function. In other ways, they are similar to the consumer models mentioned below.

(2) Consumer Models
Consumer models have included small uprights and small grands whose record system is based on key sensors and pedal sensors only.

(3)  Standard Models
Standard models have been available on small and large grands as well as studio model uprights. In addition to key and pedal sensors, they have hammer sensors that provide greater recording and calibration accuracy.

Key Hammer Sensor Text(4) PRO Models
PRO models have been available since 1998 on large grand pianos, such as the C3 (6' 1") and larger instruments. The PRO models are distinguished by key sensors, pedal sensors, hammer sensors, moving magnet sensors with key sensor servos, Silent system, and the ability to record and play extended precision MIDI data, known as XP data.

Record Mechanism
Disklaviers use a number of different sensors to determine the timing, speed of movement, and position of keys, hammers, and pedals.

Unlike consumer-quality retrofit systems from other companies, contemporary Disklaviers are distinguished by their ability to record incremental positions of the left and right pedals. It is necessary to capture incremental pedal movement in order to provide realistic playback.

Today, Yamaha’s standard and PRO model Disklaviers use sensors under every key as well as advanced gray-scale sensors on the hammer shanks in order to determine the timing of notes, the velocity with which the hammers hit the strings, and the speed of the release of each key. At the present time, these Disklavier models are the only recording pianos on the market that record with this level of precision.

Contemporary standard and PRO Disklaviers capture the complete range of piano expression and even record brushed notes (silent notes that result from slight key movements that do not produce audible sound).

Key SolenoidsPlayback Mechanism
Playback is achieved by an array of 88 solenoids, one placed under the back end of each key, as well as by solenoids that are connected to the left and right pedals. A solenoid is a coil of wire that is wound in the shape of a cylinder. Inside the cylinder is a magnetic plunger. When electricity is sent into the coil, a magnetic field is created that causes the plunger to move with greater or lesser speed. During playback, the solenoids move the keys and pedals with great precision. The solenoids in contemporary standard and PRO Disklaviers are so sophisticated that they can move the keys without the hammers even striking the strings, thus reproducing brushed (silent) notes. They are also capable of reproducing rapidly repeating notes.

MIDI and XP Data
The Disklavier stores recorded performance data in an industry-standard format called MIDI data. This means that Disklavier performance data can be played on other instruments, such as an AvantGrand hybrid piano or a Clavinova digital piano.

Standard model Disklaviers record both note-on events (hammer velocity) and note-off events (key release velocity) using the standard MIDI scale of 0-127. Left and right pedals (una corda and sustain, respectively) are recorded on the same standard MIDI scale of 0-127. The sostenuto pedal, which has an on/off function, is recorded with two values: 0 and 127.

The Disklavier PRO uses normally undefined MIDI controller messages as well as key aftertouch messages to record extended precision note and pedal data, often referred to as XP data. Note-on (hammer) velocity, key down velocity, and note-off (key release) velocity are recorded on a scale of 0-1023, providing eight times normal MIDI resolution. The una corda and sustain pedals are both recorded on an extended scale of 0-255, providing two times the normal resolution.

Performance files recorded on a Disklavier PRO play with no difficulty on non-PRO Disklaviers and other MIDI keyboards. The additional XP data is simply ignored in these situations.

Tone Generator
The modern Disklavier includes a tone generator that can produce hundreds of instrumental sounds and sound effects. The tone generator supports the industry-standard set of sounds called General MIDI (GM) as well as Yamaha’s extension of the GM sound set called XG.

These sounds are typically reproduced by speakers mounted under the piano. Alternatively, these sounds can be routed to an external sound system if desired.

Disklavier with HeadhonesSilent Mechanism
The Disklavier PRO and many standard model Disklaviers have a Silent system. The Silent system provides a so-called mute rail which, when engaged, blocks the movement of the hammer shanks just before the point where the hammers would normally engage the strings.

When the Silent system is engaged, you can listen to the sound of your playing over headphones. A special, digital sample of a concert grand piano is provided for this purpose. This digital piano sample can also be routed to speakers if desired.

Calibration
All pianos are comprised of moving parts. Over time, the physical characteristics of those moving parts change, based on wear as well as changes in temperature and humidity. These changes can affect the way in which a Disklavier records and reproduces performances.

To compensate for this, every Disklavier has an embedded calibration system that is normally accessed only by a piano technician. The purpose of the calibration system is to ensure that the piano records and plays back accurately, given the current state of the mechanical regulation of the piano.

During calibration, the piano repeatedly plays all of the notes of instrument at various dynamic levels, both with and without the sustain pedal engaged. The piano also tests the range of pedal movement of both the left and right pedals.

As the piano is being put through its paces, the Disklavier’s recording system monitors the playback system and makes subtle adjustments as necessary.

The Disklavier PRO takes the calibration concept a step further and uses moving magnet sensors with key sensor servos to monitor itself during playback, making small adjustments as necessary.

In general, it is a good idea to have the piano calibrated twice a year as well as any time that the piano has been moved.

DKC-850 RemoteE3-DKC-850 iOS Remote White 178x370Control Unit and Connectivity
Contemporary Disklaviers offer many options for MIDI, audio, network, and storage connectivity, including:

• MIDI In and MIDI Out ports.

• USB port for 2-way MIDI communications.

• audio ports for connection to:

• speakers.

• input of special performance data in audio format (known as analog MIDI).

• both input and output of time code (known as SMPTE) for video-sync recording and playback.

• Ethernet for networking.

• USB connectivity for flash drives and optional floppy drive.


Remote Control
All Disklaviers have an option for remote control. In most cases, this has been a line-of-sight remote that uses infrared signals (much like a typical TV remote). The Mark IV was exceptional in the sense that it provided a remote (called the PRC-100) that connected to the piano over wi-fi.

If a Mark IV or E3 Disklavier is connected to a local area network, the instrument can also be controlled by a free Disklavier Controller app that runs on iOS devices, such as iPhone, iPod touch, and iPad.

Disklavier Upgrades
Over the years, there have been upgraded control units for older Disklaviers. Currently, Yamaha offers an updated control unit called the DKC-850.
DKC-850 RearThe DKC-850 can be used as a complete replacement for the control unit on Mark IIXG and Mark III Disklaviers. It can also be used as an add-on control unit for Mark II Disklaviers. Although the control unit does not change the recording and playback capabilities or other built-in features of the instrument, it does provide essentially the same user experience as the control unit on a modern E3 Disklavier.*

* NOTE: When used as an add-on control unit, the DKC-850 does not provide access to DisklavierRadio or DisklavierTV.