RealPiano Expander Gem - Módulo de Timbres para Teclado - Instrumentos Musicais

The RealPiano Expander (above) belongs to the first generation of physically modelled sampled based pianos. This module was discontinued in 2000 due to unforeseen component shortage.

From the expander manual:
In collaboration with the CSC, department at the acclaimed University of Padova, Italy, Generalmusic have perfected a physical model that can accurately reproduce the real performance characteristics of an acoustic grand piano. Using the unique FFT Merge technology, developed specifically for the RealPiano series, the tonal characteristics of the finest grand pianos in the world (including Steinway, Bösendorfer, Yamaha and Fazioli) are carefully analyzed with the best results from each being implemented in the final composite sound.

The RealPiano Expander features three unique applications of sound design technology including physical modeling to simulate the internal characteristics of a piano sound board.

Natural string resonance
The first physical modeling technology, patented by Generalmusic as Natural String Resonance, allows all of the complex harmonics normally produced by the piano sound board to be faithfully produced. This means that a note's individual sound will always be slightly different depending upon which other notes are currently being held, (and consequently which strings are un-damped and free to resonate in sympathy). If you hold a low C and let the note decay, the strings for that note are still un-damped for as long as the key remains depressed. If you now strike another C higher up the keyboard, (staccato), you will hear the sympathetic resonance of the low C strings in response to the new note played. This natural effect replicates exactly what happens on a grand piano. If you experiment with different combinations of notes you will hear harmonic colors particular to each. Because this effect is produced by physical modeling and not by samples or DSP effects, the result is musically and technically accurate simulation of a piano's sound board and virtually infinite combinations of harmonics can be produced.

Damper physical model
The second technology, patented by Generalmusic is Damper Physical Model. Although it looks like an ordinary damper foot switch, the special continuos damper pedal for the RealPiano Expander is not a switch but, instead, a continuos pedal which accurately simulates the effect of the dampers being moved closer to or further away from the strings of the piano. Because of this, effects such as partial or half damping can be achieved. The dampers can even be slowly squeezed back against the strings. When the damper pedal is depressed, the damper physical model will simulate the effect of sympathetic resonance being produced by the un-damped strings. Even if you are using a standard switch type pedal, you can hear the effect of the Damper Physical Model by comparing the sounds of notes played in the highest octave of the instrument with and without the damper pedal depressed.

Advanced Release Technology
The third and final technology applied to the piano sounds in the RealPiano Expander is Advanced Release Technology, (patent pending). Sample based electronic pianos traditionally use envelope generators to control what happens when a key is released. This simply allows the sample loop to continue for a set period of time until its amplitude is reduced to zero by the envelope generator. In an acoustic piano, vibrating strings are silenced by the action of a damper making contact with the string. When this happens, depending on the velocity with which the key was struck and the length of the string itself, certain frequencies are damped earlier than others producing a distinctive harmonic ring as the different frequencies in the string's tone dissipate throughout the piano sound board. The Key Release Model in the RealPiano Expander simulates exactly this feature with complete accuracy throughout the note range.

The RealPiano Expander module offers a complete set of MIDI connectors (In, Out and Thru), stereo outputs, a serial port (mac interface), 32 sounds, different chorus/flanger/reverb effects, programmable sound presets, tuning in 0.5 steps, easy transpose buttons, 2 sound layers for simultaneous playing and a split function. Jack for stereo headphones. Optional accessory is the GEM continous damper pedal for optimal use of the pedal effects (damper physical model). The expander and Pro 1 stage model offer 64 notes polyphony while the Pro 2 offers 128 notes. Otherwise, the sound is exactly the same between the three.

In-depth review of the RealPiano Expander
As I have myself been an owner of the expander module I will here share my, and others, experience about it, both good and bad. Good to know for those who are thinking about buying it as a complement to their current digital piano.

Firstly, you can use this piano module with any midi keyboard available, that is if it has a midi out port. It doesn't matter how good or bad the keyboard is but it will do justice if you use a good midi keyboard with a decent hammer touch. You can use any of the digital pianos available, the sound of the module will take over and offer a 64 notes polyphony.

For a stage musician this module still comes very handy and delivers a very good piano sound. My experience of the expander is that it is, despite the limited sample memory, very expressive as a whole and achieves a close to true acoustic accuracy. I strongly recommend that you make use of an external reverb (as the built in reverbs are not sufficient enough) and an equalizer to tweak the sound to your personal taste.