AES Section Meeting Reports

Los Angeles - October 29, 2011

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The October gathering of the LA section of the AES en- joyed a presentation by David Kreisberg on the technology behind the Yamaha Disklavier line of player pianos, and its applications in music performance and recording. Kreis- berg is a well-respected expert on the system, and has a long history of creating software and producing content for modern computer-based reproducing pianos. He took the group through the history and engineering of the Disklavier system, and shared several examples of its performance.
Conceptually similar to the paper-roll based player pianos prominent at the turn of the last century, the Disk- lavier was introduced in 1987. From its conception, the design called for the Disklavier portion of the instrument to not affect the sound or "feel" of the acoustic piano for tradi-
tional playing. With that in mind, the engineers were careful to design a system that did not mechanically interfere with the piano portion of the device. In fact, each Disklavier begins
its life as a standard Yamaha acoustic piano with the Disklavier technology available as an option. Unlike some of the other computerized electro-mechanical systems on the market, Yamaha does not make the Disklavier system available as a retrofit; rather the system must be installed at the factory at the time the piano is built.
To capture a performance made on a Disklavier, the system uses a pair of grayscale shutter sensors for each of the keyboard's 88 keys. One of the two sensors monitors key presses, and the other observes the hammer striking the string. This system enables an onboard computer to capture the timing and velocity of each keystroke, recording it as MIDI data. There are also additional sensors on the shift and sustain pedals to record their movements as well.
Playback of performance files is achieved using solenoids that physically actuate each key, in a manner identical to normal playback of the piano.
The entire system was demonstrated by David inviting a volunteer from the audience to play a short jazzy piece, which was then played back perfectly by the Disklavier.
David explained that soon after the Disklavier's introduction, musicians and producers began using it for record- ing projects. Because it is at its core a MIDI device, the Disklavier proved to be the perfect tool for recording a piano performance. Edits could be made in software to correct errors or make artistic tweaks, and then a recording could be made during playback of the corrected performance in a single take. This concept also proved helpful in providing piano music composers with a way to make a more economical high-quality recording of their work. They can record a perfor- mance on a small, upright Disklavier in their living room and email the file to Kreisberg, who can then play back and rec- ord that same performance on a 9' concert grand piano in his recording studio designed for pristine piano recordings.
The Disklavier is capable of additional interesting applications, such as remote live (albeit slightly delayed) per- formances. While the more-modern systems employ Ethernet, Kreisberg described a performance from the late 1990s in which jazz pianist Roger Callaway was to play in a duet onstage in Sweden but was unable to attend due to illness. A Macintosh was used in Callaway's home studio to convert his Diskclavier's live MIDI stream to ASCII text for transmis- sion over a modem. A mirror system was attached to a Disklavier onstage in Stockholm, which replicated Callaway's performance live on stage, accompanied by the clarinetist for the evening's duet!
Realizing there was a market for professional use of the system, Yamaha introduced in 1997 a Pro model, which provides 32 notes of polyphony (to the standard model's 16) and expands the resolution of the key-velocity measure- ment from 7 bits to 10 bits.

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