Technology - GEM Prp700 Owner's Manual

owners manual
The Prp700-800 digital pianos are powered by an advanced technology called DRAKE. DRAKE (Dsp-Risc-Advanced-
Keyboard-Engine) we feel is the most advanced musical dsp in the world. It's 32-bit and 50-MIPS internal structure along
with a totally programmable software architecture makes this processor so fast and powerful that any kind of algorithm,
from Wavetable to Physical Modeling can be implemented in real time, either in generation or in post-processing. Using
the Physical Modelling power offered by DRAKE, a number of new algorithms which replicate some of the world's most
famous vintage instruments like Rhodes™, Wurlitzer™ and Clavinet™ has been created. DRAKE has found unanimous,
enthusiastic appraisal from many experts in these fi elds along with professional musicians around the globe.
Physical Modeling
Physical Modeling is a method of sound synthesis based upon a mathematical model which de scribes the physical construction of
the instrument being simulated. Unlike sampling technology, in which an existing sound is simply recorded at a particular moment
in time, (to remain the same for ev er), the sounds produced by a Physical Model continuously react and respond to the player's input,
maintaining all the small nuances and im per fec tions which produce the most reliable subconscious as sur ance that the in stru ment
being played is the real thing. A sampled sound can be likened to a "snapshot" of a particular mo ment in time during which an
instrument is being played. It's like taking a photograph. The goal of Phys i cal Mod el ing is instead of recording the fi nal audible
product of a in stru ment like an electric piano, we replicate all the elements which are incorporated into its con struc tion. If the
physical model is constructed carefully and accurately with meticulous attention to detail, the re sult ing sound should be ex act ly like
the real thing and, more importantly, the experience of playing and interacting with the in stru ment should be similarly convincing.
In the Prp700-Prp800, all the acoustic piano sounds are created by combining sample playback with Natural String Resonance,
Damper Phys i cal Model, Ad vanced Re lease and FADE tech nol o gies, (described below). Other instruments such as RHODES, WURLI
and CLAVINET are created using pure Physical Modeling.
Natural String Resonance
This physical modeling technology, allows all of the complex harmonics normally produced by a piano's sound board to be faithfully
re pro duced. 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 sym pa thy with the note played). If you
hold down 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, (stac ca to), you will hear the sympathetic resonance of the low C strings in response
to the new note played. This natural effect replicates exactly what hap pens inside 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 a musically and technically ac cu ra te simulation of a piano's sound board and virtually
infi nite combinations of har mon ics can be produced.
Damper Physical Model
Another technology is the Damper Physical Model. Whenever the damper pedal is depressed, the damper physical model simulates
the effect of sym pa thet ic resonance being produced by the strings which the action of the pedal has now left free to res o nate. Use
the damper pedal to hear the effect of the Damper Phys i cal Model by comparing the sounds of notes played in the highest octave
of the in stru ment with and with out the damper pedal de pressed.
Advanced Release Technology
The particular sound of a piano string being stopped by a damper while in motion is replicated by the unique Ad vanced Release
Technology. Sample based electronic pi anos traditionally use a en ve lope generator to control what happens when a key is released.
This easily allows the sample loop to continue playing for a set period of time until its amplitude is fi nally reduced to zero by the
envelope generator. In an acoustic piano, vibrating strings are silenced when a felt damper comes into contact with the moving
string. When this happens, depending on how hard the key was struck and the length of the string itself, certain frequencies
are damped earlier than others while some other frequencies are even accentuated, (anyone who ever studied how to produce
harmonics on a guitar will recognize this principle). This produces a distinctive harmonic "ring" as the different fre quen cies in the
string's tone dis si pa te through out the piano sound board. This Advanced Release Tech nol o gy in the Prp700-Prp800 simulates this
phe nom e na with complete accuracy throughout the 88 note range.
FADE - Filter Algorithm Dynamic Emulation
Reproduction of the complex harmonic and dynamic changes which take place as you increase or de crease the velocity of a key-
strike on a piano have always presented a serious problem for traditional sam ple-playback tech nol o gy. The only practical way to
re pli ca te these changes has been to select three or four distinctly dif fer ent levels and switch between these according to the velocity
with which the key is struck. This produces the unnatural effect of having clearly audible steps between different velocity levels,
further diminishing the authenticity of the sound reproduction. Unlike the velocity-switching meth ods used in other elec tron ic pianos,
unique FADE technology utilizes only one specially confi gured sound source per note. At the heart of the FADE engine is a extensive
database which can provides the precise harmonic content of any note played at any velocity level. Whenever a note is played, the
FADE engine analyzes the velocity of the key-strike and constructs, in real-time, a model of the nec es sary har mon ic con tent for
that particular note played at that velocity. The note's sound source is pro cessed by the FADE engine with appropriate harmonic
content being added or subtracted ac cord ing ly. In practice, FADE tech nol o gy provides seamless transition from pianissimo all the
way through to for tis si mo for each note without any audible switching.
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TECHNOLOGY

Prp700-Prp800