The various forms of Disklavier are essentially modern pianos that use electromechanical solenoids and optical sensors connected to LEDs allowing them to play notes and use the pedals independently of any human operator. Most models are based upon real acoustic pianos and have been engineered such that the sensors and electromechanical elements do not interfere with or affect the normal playing of the instrument. They include the ability to store data, including performance data played by a human pianist, and then use that data to replay / reproduce the performance. Disklaviers also have inputs for data from MIDI and from several storage devices including floppy disks, CD-ROM, serial cables, and USB.
Disklaviers have been manufactured in the form of upright, baby grand, and grand piano styles (including a nine-foot concert grand), along with a product aimed at the professional market called the Disklavier Pro. There is also a digital piano version from Yamaha's 'GranTouch' range. It is claimed by the manufacturer that the Disklavier Pro is able to reproduce key and pedal strokes with greater precision than the standard Disklavier instrument. It is the official instrument of the Minnesota International Piano-e-Competition, which by 2009 was in its 6th year.
Mark II, Mark IIXG, Mark III 
Improvements have included the ability to record and play standard midi files from and to a floppy disc, an on-board synthesiser soundsource (the XG Tonebank), the addition of synchronous audio tracks (combined with midi) via CD Rom (for playback), the SmartKey system of learning and entertainment for beginners, Karaoke functions, and various multi-tracking recording functions. With the release of the Disklavier III, Yamaha introduced the ability to play sampled sounds via headphones or other audio outputs, without the hammers actually striking the strings and therefore allowing 'silent playing'.
In 1999, "Disklavier Pro" was introduced to the American market, the "II Pro". A key selling feature of this version was a claim of greater playback accuracy than had been possible with previously available models. The Pro made use of a proprietary enhancement of MIDI data, which subdivided the timing information in an effort to allow greater precision. Rather than using the standard 127 levels of midi velocity, Yamaha introduced 1023 levels for KeyAfterTouch, NoteOn and NoteOff. A similar principle was applied to the pedal performance data, using 256 increments of measurement in an effort to allow finer capture and reproduction of, for example, half and quarter pedaling by the player. These developments allowed Yamaha to claim a greater overall accuracy in the reproduction of an original piano performance.
Mark IV 
Introduced in 2004, the current Mark IV series of Disklaviers utilizing an embedded Linux operating system includes wireless (WiFi) communication, allowing a user to control the piano via a PDA-style controller, tablet-style controller or, more recently, iPad app. The Mark IV series includes an 80-gigabyte hard drive and an unobtrusive console, located under the left side of the keyboard. A MIDI interface allows the connection of external devices allowing control of external sound sources, MIDI-based recording or for triggering and playback of the piano from an external keyboard or sequencer.
Another development included in the Mark IV is 'v-sync', making use of an on-board SMPTE time code generator. A video camera connected to the unit can then be operated in sync with all key and pedal strokes recorded during a performance.
Pre-recorded performances using the enhanced proprietary MIDI protocol have been made available by the manufacturer.
Specialized use 
In 2006, Matthew Teeter and Chris Dobrian, researchers at the University of California, Irvine, developed third-party Disklavier software controller running on Windows, Mac and Linux operating systems, which replicated the functionality provided by the PDA/Tablet PC remotes. The software and its source code were made freely available. In November 2007, Kevin Goroway used that example code to create DKVBrowser which is an open source project. This software is also multiplatform, and has provided features that are not available on the proprietary interfaces provided by Yamaha, such as wildcard searching.
The software running on the Disklavier IV and IV Pro onboard Linux control computer continues to undergo development and the manufacturer makes firmware updates available to users.
As with other MIDI instruments, one potential benefit of the readily-edited MIDI data output by a Disklavier is in the professional recording domain, where a recorded performance could be edited, allowing the correction of minor errors after a take.
Disklavier pianos have been used by music teaching studios in the United States and, to a lesser extent, in other parts of the world. There are instances of the instrument being used by teachers and students to illustrate strengths and weaknesses by studying the reproduction of a particular performance.
Yamaha set up a project to allow data communication between two or more Disklavier IV pianos with the intention of supporting real-time 'at-a-distance' teaching sessions and collaboration among pianists. Yamaha has produced software named "Remote Lesson" which has been demonstrated using Internet2 connection, as well as more traditional connection methods such as T1 and DSL protocols, between two Disklavier pianos separated by several thousand miles. The technology aims to reproduce the actions of a player on one instrument on another connected instrument, using the 'Remote Lesson' software, at a long distance, using high-speed broadband connectivity. Understandably however, data transfer speeds available over the generally-available public Internet are currently insufficient for absolute real-time operation. There is always a delay, of at least one and up to several seconds, between performers. Disklavier midi data is buffered within the instrument, owing to internal timing and velocity interpretation -- hence the built-in delay between two or more potential users in different remote locations.
Additionally, videoconferencing has been utilized as an additional layer of communication between the participants, although it has been hampered by some minor technical issues involving a form of feedback. Yamaha has not released Remote Lesson to the general public, but has said that it expects to eventually include it in software upgrades for the piano.
- Innovative Grand Piano Could Tune Up a Flat Industry, Los Angeles Times, April 27, 1993
- Brandom heads Disklavier marketing, Music Trades, July 1, 2007
- Musicians News
- Report on a new kind of at-a-distance piano lesson, USC News, February 15, 2007.
- University of Southern California jazz studies professor Shelly Berg, as quoted in USC News, February 15, 2007.
- Music Teachers National Association Showcases Yamaha Disklavier "Remote Lesson", Yamaha press release, May 11, 2007.
- Pro 2000 description at Yamaha Corporation of America
- Disklavier at Yamaha Corporation of America
- MIPeC Hi-Def and e-SEQ midibank at Minnesota International Piano-e-Competition
- Disklavier World Webpage - PUBLIC DOMAIN (FREE) piano music in FIL (e-SEQ) & MIDI formats - 9,782 sequences & "live" performances.
- Disklavier World Blog - PUBLIC DOMAIN (FREE) piano music in FIL (e-SEQ) & MIDI formats - 9,782 sequences & "live" performances.
- Disklavier Software Webpage - Isadar - original new-age styled solo piano music in e-SEQ Disklavier format - performances on 2DD diskettes or digital download.
- Image of a Disklavier Grand
- Livecoding a Disklavier - playing a disklavier with a computer program.