By Ralph Raiola,
The task of building a piano capable of producing the sound quality expected and sought after by the world’s best musicians is a difficult enough task. Add modern digital features—built-in recording and playback, data storage, an LCD touchscreen interface, wireless remote control, and more—into the mix, which is what Yamaha has been doing for years with its Disklavier series, and there is always the potential for disaster.
The latest in member of the family—the Disklavier Mark IV—is a real design marvel, one that embraces the basic philosophy of mechatronic design, and then pushes it to the bleeding edge. According to Disklavier Marketing Manager Bill Brandom, members of the Japanese engineering team are very familiar with the principles of mechatronics.
“They said that all of the key technologies incorporated in the Disklavier (e.g., the sensing system and drive servo system working together in an acoustic piano) are mechatronics,” said Brandom.
Yamaha’s Disklavier Mark IV acoustic piano includes a host of electronic systems and components–such as an HDD, solenoids, sensors, and a Linux OS–to enable unprecedented capabilities from such an instrument.
What is a Disklavier?
My first introduction with the Mark IV came late in 2007 during a piano recital at the Yamaha Artist offices in New York City. The kicker was that the player—29-year-old Edisher Savitski—was giving the concert from the Disklavier in his South Bend, IN home. The New York audience was being
entertained by an unmanned piano that was emulating his performance.
Besides being high-quality acoustic instruments in their own right, Disklavier pianos are notable for their ability to record and playback a performance, akin to modern-day player pianos on steroids. The Mark IV is a collection of systems that enable highly accurate recording and reproduction of the piano performance. Several other systems are also included to provide additional functionality for the pianist.
Brandom stressed that none of the various built-in electro-mechanical systems interfere with the actual performance of the acoustic piano itself. “This is very important because the Disklavier is an acoustic piano first.”
Each of the piano’s 88 keys have a gray scale attached underneath.
The central signal processor is the heart of the Disklavier, and is charged with controlling the recording and playback of the Disklavier system. The processor also digitally controls the power supply.
One of the most impressive aspects of the Mark IV is its sophisticated sensing system. The system uses noncontact optical fiber / gray scale shutters on the keys and hammers.
The gray scale hammer-sensing system traces the hammer position from the time a key is pressed until it is released. The gray scale key sensor monitors every motion of the key and hammer—even on rapidly repeated notes—with meticulous precision and the softest touch. This technology
allows the piano to calibrate itself.
A standard Mark IV can capture 128 levels of expression, while a Mark IV PRO can capture 1,024 levels of expression.
A noncontact digital optical sensing system is used for the pedals (continuous sensing for the damper and shift pedals, and on/off sensing for the sostenuto/sustain pedal). Incremental pedaling on the standard Mark IV is 128 steps and 256 steps on the Mark IV PRO.
This side view a single key shows mechanical devices, the hammer gray scale, and piano string.
Recording and playback
The playback system is controlled by a DSP servo-drive system that plays back the keys and pedals. This servo control system continuously monitors the movement of each key and pedal movement and precisely recreates every detail of the original performance. The playback part of the system is only engaged during the Disklavier playback.
Recordings are captured using MIDI. The Mark IV PRO records at a much higher resolution than MIDI, which Yamaha calls XP. With version 3.0, the standard Mark IV and Mark IV PRO have the ability to record .wav files of a piano performance and/or anything coming into the mic input.
A side view of a key shows the key gray scale and the key sensor rail.
The heart of the I/O center is the MontaVista Linux Pro 3.1 operating system. Additionally, this area houses the piano’s 80-Gbyte hard drive used for data storage. The I/O center contains the main processor board, the MIDI/Audio USB interface board, and tone generator board.
The I/O center also allows the Disklavier to connect to the Internet. Users can to the company’s DisklavierRadio, a MIDI data-streaming service that provides the customer with music that plays their piano 24/7.
A wide range of external equipment—TVs, cameras, computers, home networks, and various other audio equipment—can be connected to the Disklavier through this center.
Song data is stored to an internal hard drive. Song data can be transferred to Mark IV hard drive from a floppy, USB thumb drive, CD, through a network, and then over the Internet.
The Mark IV uses a PRC-100 Wi-Fi remote controller that allows for background-music control from locations outside of the room with the piano. The remote features a 3.5-in.color LCD touchscreen, and with the latest version, Version 3.0, the piano can also be controlled by a PC or MAC Mac using a function called Virtual PRC.
Making music – how it happens
When a person plays the piano, i.e. pushes down the keys on the keyboard, the playback system pushes the keys up from the rear to accomplish the same key stroke. The hammers in a piano travel to the string as a result of the keys being depressed. The faster keys are depressed the harder the hammers hit the strings and the louder the note is played.
When a person plays the pedals, the Disklavier damper-and shift-pedal solenoids pull the back of the pedals up to accomplish the same pedal stroke.