Sampling is one way of placing grand piano sounds under computer control. Now Bosendorfer have come up with an entirely different solution that exactly recreates a musician's performance.

ONE OF THE FUNDAMENTAL limitations of sequencing is that it can only be used with electronic instruments, right? Wrong. Bosendorfer, one of the great piano manufacturers of all time, have developed a computer-based recording system that is capable of recreating a performance by "playing" a piano exactly as if it were being played by a musician.

The system is known as the Bosendorfer 290SE. It's a full-size, 97-note grand piano, identical in most respects to its conventional counterparts, except that it can be put under computer control. Not only does the system allow a performance to be recorded, edited and reproduced, but there is no quality loss because the computer is linked to a series of linear motors in the piano itself - these are what are used to "play" the piano exactly as a musician would.

Bosendorfer claim that the 290SE is "the world's first perfect repeat performance" for piano. A lot to claim, whichever way you look at it. But it soon becomes apparent that the 290SE is no electronic pianola; it's a bold step forward that could have important implications for computer-based music systems, scorewriting and education.

Before we go any further, it's important to remember that the great majority of Bosendorfer's clients are not involved in contemporary music. Hence right from the beginning, the system simply had to be transparent as far as the player was concerned, capable of being operated with complete confidence by computer illiterates, and of withstanding the most critical listening tests - something a sample-based system could never do.

It's also important to bear in mind that this system is very much an integral part of the piano, and that a retrofit is not considered feasible. In fact, Bosendorfer's traditional handbuilding techniques mean that there are minute differences between each piano anyway. In order to ensure the greatest degree of accuracy between recording and playback, as well as between one piano and another, there are self-diagnostic calibration programs built into the software.

The System

HERE'S HOW THE piano works. Every key and hammer on the 290SE is fitted with an optical sensor, as are the sostenuto, sustain and soft pedals. Every sensor is scanned at 1.25microsecond intervals, and the information digitally stored. By noting both key movement and hammer velocity, a precise record of the player's technique can be recorded. Even light key depressions, which result in no hammer strike, are stored.

The optical sensors have no effect on the piano action, and this is also true of the linear motor pistons that are used for replay. These are located the other side of the pivot point on each key. During a recording, the pistons are a fraction away from the keys, while during replay they press upwards to imitate the original depressions of the player.

That, and a few PCBs, describes the difference between the 290SE and a normal Bosendorfer grand piano. In order to understand the true potential of the system, we must turn our attention to the computer.

Bosendorfer's design team have opted to use a dedicated computer, with four custom boards. These are keyboard interface, activator or playback interface, disk drive interface and CPU. Connections on the back of the computer allow the information from the piano to be dumped to the 8" dual disk drives or to another medium, such as normal magnetic tape. Depending on the density of information stored, a single side, double density floppy will hold around an hour of playing - enough for most purposes. Alternatively, storing to normal recording tape is real time. This would obviously be advantageous if the performance information were synchronised to the rest of a sound track. For editing purposes, the disk is a far faster loading method and many users will probably choose it as their sole storage medium.

At present, recording to multitrack is the only way of synchronising, although a SMPTE card will be available later. A MIDI card is also planned, but this involves some compromises. Put simply, the Bosendorfer system stores about ten times more information than MIDI can, so it's inevitable that a lot of subtlety will be lost if MIDI is used to input. Somehow, it's hard to imagine that the feel of the majority of MIDI keyboards would make them a suitable source, either. On the other hand, some players may enjoy the prospect of using a grand piano as their mother keyboard, even if it does mean that control over many of the parameters have to be external to the instrument itself. A grand piano with pitch and mod wheels really wouldn't look right.

"The system is an integral part of the piano and a retrofit is not feasible... and hand-building means there are minute differences between each piano anyway."

In terms of hardware, the remainder of the package consists of a standard ASCII keyboard with numeric pad and a 12" monochrome monitor.

On the software side, the Bosendorfer is disappointing on a number of counts, but especially in the way in which information is presented. Perhaps we're spoilt by some of the clear, friendly and encouraging graphics used by some of the excellent MIDI software around now, but the tabulated information offered by the Bosendorfer is really rather bland, being vaguely reminiscent of the Rhodes Chroma/Apple II system of a few years ago. In its defence, it must be said that the main purpose of the software is accurate recording and reproduction, and not composing. Clearly, the main effort has gone into making the basic functions as accessible as possible. Any editing functions beyond that may be easily ignored if you're not interested in them.

For editing purposes, there is a five column display. From left to right this shows:

Time in 800/th of a second (1.52microseconds). This can be changed to a resolution of 100/th of a second for fast editing. Reducing this resolution down to 24ppqn is one compromise that would have to be made for MIDI.

Note Number MIDI convention is used, so middle C equals 60 and so on.

Name ie. Bb, C and so on.

IHV stands for inverse hammer velocity; 10 is a very loud strike, while 1200 is extremely quiet. In the available number of dynamic values, the Bosendorfer system exceeds MIDI by an approximate factor of ten.

Release Time relates to the point at which the key is no longer held down.

Editing is performed by altering values with the computer keyboard. It is not possible to drop-in from the piano keyboard, partly because there is a buffer of around 0.75 second. But again, the intended application of the display is to allow a maestro to correct a solitary note, or a student to analyse a performance.

It is possible to add or delete notes, and pedal information can also be displayed.

"Bosendorfer have incorporated a code which means editing can be carried out only on the system the music was performed on."

Now we come to the Merge program, which is basically a cut-and-paste facility, allowing sections of music to be added or deleted. The key can be transposed and the tempo altered - the latter feature, for example could be useful for film work, where a piece has to fit a predetermined slot. Bosendorfer also envisage applications for the composer, allowing sections to be joined in various permutations.

Obviously concerned with the integrity of performers, Bosendorfer have incorporated a code into the computer. This means that editing can normally be performed only on the system the music was performed on. The company is also concerned with protecting the secrets of its system, hence digital information is masked with white noise and random storage techniques are used.

Perfection?

BECAUSE A PIANO divorces the player from the strings with a series of mechanical levers, and because Bosendorfer have chosen to use very high levels of resolution, the 290SE appears to work impeccably. Whether 'perfect' is the appropriate word is debatable. Is anything perfect? Probably not. But certainly, this system will reproduce music played on a grand piano with greater accuracy than any other medium, digital recording included. Live, it has the advantage of eliminating amplifiers and speakers from the reproduction chain.

There's no end of applications for the 290SE, at least in theory. The maestro could perform a piece in his living room, check the program for accuracy and send the digital information by modem to the recording studio. Let the engineers worry about recording techniques, while the computer plays the studio's Bosendorfer over and over.

In reality, though, this probably won't happen. For one thing, the technique would only be totally suitable for unaccompanied pieces. Can you imagine a 70-piece orchestra trying to perform the perfect interpretation to a computer stored piano part'

For recording purposes, certain facilities are undoubtedly useful - primarily the ability to perfect a piece without drop-ins. For commercial work, the ease with which a piece can be time-compressed is also impressive.

But undoubtedly, the system as it stands should have greatest impact on the educational field. The ability to see as well as hear the notes, plus the way in which a master performance can be repeated, must be of value to any serious music student.

The final category of user will probably be the superstar composer/performer such as Oscar Peterson. For that market, Bosendorfer probably need to expand the interfacing capabilities of the system, even if it does mean that the full subtleties cannot be transmitted to other instruments. A Synclavier with a Bosendorfer interface would be some instrument.

Inevitably, the Bosendorfer system is expensive. A concert grand alone costs about £35,000, and the total computer system roughly doubles that figure.

But these are early days. It may be that Bosendorfer, or another company, will eventually produce a similar system that can be retro-fitted to the upright piano. And that, given more of an accessible scale of pricing, would be a valuable addition to any computer-based songwriting system.

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