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User Manual – Sound generation parameters
TUNING UNISON
Range: -50...0...+50
NRPN MSB=0, NRPN LSB=4
Data Entry MSB Range: 14...64...114
Allows you to vary the relative tuning of the members of a doublet or triplet in order to change their tuning from "unison"
to "detuned".
Each piano note corresponds to one, two, or three strings. Tuners typically tune the string couple or triplet not exactly
to the same frequency, in this way they get the well know beating phenomena that the player perceives as timbre
fluctuation during sound evolution. If such detuning is exaggerated the sound is perceived as completely out of tune,
i.e. a Honky Tonk piano sound.
A 0 value corresponds to the standard tuning with a small beat amount, while +50 corresponds to the maximum
detuning and -50 corresponds to the perfect unison tuning.
TUNING STRETCH
Range: -50...0...+50
NRPN MSB=0, NRPN LSB=5
Data Entry MSB Range: 14...64...114
Allows you to adjust the deviation from the ideal piano tuning.
Because the overtones of the piano string are not in a perfect harmonic relationship, the piano is not tuned according
to the equal temperament, but according to a particular frequency distribution (known as Railsback distribution) for
which low notes are undertuned and high notes are overtuned. The Stretch Tuning parameter allows you to modify
such distribution.
A 0 value corresponds to the standard Railsback tuning, while +50 corresponds to the enhanced Railsback tuning and
-50 corresponds to the equal temperament tuning. The effect can be noticed by listening to the beats that are created
between the partials of two notes an octave apart.
FINE TUNING
Range: -50...0...+50
NRPN MSB=5, NRPN LSB Range=21...108 (A0...C8)
Data Entry MSB Range: 14...64...114
Allows you to tune each note. The effect of this parameter is relative because it is added to the
parameter and master tuning setting.
STRING STIFFNESS
Range: -50...0...+50
NRPN MSB=0, NRPN LSB=6
Data Entry MSB Range: 14...64...114
Allows you to control the string flexibility which affects the regularity of harmonic distribution of the overtones.
Piano strings are generally stiffer than those used in other stringed instruments such as the guitar. A stiff string is no
longer perfectly flexible and gets some of the characteristics of a metal bar. The overtones frequencies of a flexible
string have integer ratios (harmonics) to the fundamental. This relationship does not hold for the overtones of a stiff
string, where the frequency distance of neighbouring overtones increases as a function of frequency, adding a bell-
like character to the sound.
STRING DUPLEX VIBRATION
Range: -50...0...+50
NRPN MSB=0, NRPN LSB=7
Data Entry MSB Range: 14...64...114
Allows you to control the amount of sound produced by duplex strings.
In several modern pianos the short portion of the string that is located between the Bridge and the Hitch pin is tuned in
order to resonate sympathetically with a harmonic relationship to the corresponding notes. These additional short
strings add brilliance to the treble notes of the piano.
STRING LONGITUDINAL VIBRATION
Range: -50...0...+50
NRPN MSB=0, NRPN LSB=8
Data Entry MSB Range: 14...64...114
Allows you to control particular sound components called "phantom partials".
The main mode of a piano string vibration occurs along an axis perpendicular to the string itself (transverse motion). At
the same time, the string can vibrate along its axis (longitudinal motion). The hammer excites the string mainly along its
transverse axis, but, for large amplitudes, some energy is transferred from the transverse to the longitudinal motion.
This type of vibration produces special components (phantom partials) that give a metallic character to the sound.
The Longitudinal Vibration effect can be better heard by playing fortissimo on lower notes up to the 3rd octave.
EN - 6
Stretch Tuning
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