Virtual Guitar
Physics-based Modelling of Musical Instrument Sound - A Virtual Guitar
[Master
thesis project by
Guillem Juncà, performed at
DTU (Tech. Univ. of Denmark),
Dept. Mech. Engn.,
Section of Solid Mechanics,
supervised by Jon Juel Thomsen,
Niels Fuglede, and
Emil Bureau]
Hear
sounds - see
abstract, illustrations,
and publications]
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Hear Sounds from:
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Neck pickup |
Bridge pickup |
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Real
guitar string
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Synthesized from math. model for
string vibrations
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Ideal string (no bending stiffness, perfect
harmonicity..)
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Non-ideal
string (bending stiffness, anharmonicity,..)
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Press the play-buttons in
the first row to hear the sounds recorded from the real guitar (Fender
Telecaster, output from neck- and bridge-pickup resp., with low E string
plucked open at 15 % string length from the bridge saddle).
Press the
play-buttons in the second and third rows to compare to the sounds synthesized
from mathematical models of, respectively, an ideal and a non-ideal (i.e.
closer to real) string, plucked similarly as the real E string. The
synthesized sound is obtained by solving the underlying partial differential
equations approximately using mode shape expansion, and playing the
resulting time series solutions through the computers soundboard. Details
are given in [1].
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Abstract
The synthesis of electric
guitar string sound based on the structural behaviour of the instrument is
investigated. A first step for this is to identify the characteristic features
of guitar sound, and which elements are responsible for them. These features can
be divided into those related to the initial spectral distribution, and those
related to the temporal decay of spectral components. Analytical, numerical and
experimental methods are employed to study the contribution to the produced
sound of the following elements: String motion, string bending stiffness, string
stretching / non-constant tension, guitar structure, energy losses, string
precession, and the magnetic pickup. Two different models are used to synthesize
guitar string sound: A simple analytical string model (taking into account also
bending stiffness and external and internal damping), and a detailed FEM model
(taking into account also vibrations of the guitar body and neck). The computed
/ synthesized sound from even the simple model compares favourably to the
recorded sound of a real guitar, as long as bending stiffness and a proper
damping model is included. Keywords: String vibration, guitar, sound synthesis,
inharmonicity, string precession, string stretching.
Publications
[1] Juncà, G. and
Thomsen, J.J.: 'Structural mechanics based synthesis of guitar string
sound' (submitted for journal publication)
[2] Juncà, G.,
Physics-based Modelling of Musical Instrument Sound - A virtual guitar,
master thesis, Technical Univ. of Denmark, Dept. of Mechanical Engineering,
2013. [Available
online, requires DTU login].
[J.J.
Thomsen /
]