48
Parameters
The
Global
,
Pick/Fingers
,
Strings
,
Hammer
,
Mute
and
Palm
modules are related to the
modeling of the individual strings of the guitar. The
Body
module on the right of the guitar shape
represents the body of the guitar and allows one to adjust its behavior. The different knobs in this
view are so-called
offset
knobs. Each of them is related to a specific parameter of the strings or body
of the instrument. They are used to vary the value of a parameter around its current value, in other
words the value visible when selecting individual strings. In the case of the strings parameters,
these offset knobs alter the value of the same parameter for the six strings at once.
Note that after varying parameters with these offset knobs, it is possible to apply the changes
to the parameters. This is done by clicking on the down-pointing arrow located on the right of
the module labels and selecting the
Apply Offset
command. This will add the offset value to the
current value of the parameter, move back the offset knob to its center position and update the knob
position in the individual string views.
6.2.1
The Strings Module
In an acoustic guitar most of the sound we hear is radiated from the body
of the instrument. The strings themselves radiate just a small amount of sound
directly but it is their vibrations that are transmitted to the body of the guitar,
through the bridge, where they can be radiated efficiently. It is also the strings
that fixes the pitch of the sound we hear depending on their effective lengths.
In a real guitar, the material of the sting affects the sound of the instru-
ment. For example, the sound of a metal string is brighter than that of a nylon
one. The
Tone
knob controls the decay time of high frequencies in the sound
relatively to that of low frequencies which is a parameter related to the ma-
terial of the string. Turning this knob clockwise enhances high frequencies
resulting in a more metallic sound while turning the knob anti-clockwise has
a damping effect on high frequencies.
Strings are usually considered to be harmonic meaning that all the frequency components of
the sound appear at frequencies that are multiple integers of the fundamental frequency of the note
being played. Real strings, however, are not perfectly harmonic due to the fact that there width is
not exactly constant along their entire length. As the inharmonicity is increased, we will say that
the sound becomes more and more dissonant. In
Strum
, the amount of inharmonicity in the sound is
controlled using the
Inharm
knob. Turning this knob clockwise detunes the partials toward higher
frequencies while turning it anti-clockwise reduces the inharmonicity of the strings.
The
Coupling
knob is used to control the amount of beating in the sound. Turning this knob
to the right increases the amount and frequency of the beating while turning it to the left reduces
it. This beating effect is characteristic of real guitar strings, it is due to the coupling between two
different components in the motion of the string as will be explained in more details in Secion 6.6.1
hence the name of this knob.
