mechanical device was conceived so as to guarantee objective repetitiveness
of stimulation during sound recording. This device was conceived and created
at the university "La Sapienza" in Rome, Italy, Faculty of engineering,
under the direction of professor Enzo Marchetti of the Department of mechanics
The device is furnished with a silent electric scaling engine with low speed
rotation velocity, linked to a graduated metallic pole, and sets in motion
a plectrum which pluckes the guitar string at constant impulse and velocity.
The plectrum is perpendicular to the tested string, and placed at the proper
height represented by a stop by a tangent screw .
device has been designed so as to record and measure sound emission of the
guitar soundboard in conditions as near as possible to those of human performance.
The guitar is placed on a woollen-sponge cushion which isolates it from
the bottom of the board of the mechanical device so as to avoid vibrations
which would alterate acoustic parameters, and is kept firm by isolator thicknesses
set so as to guarantee orthogonal levelling, measured by a spirit level.
To conclude, the tested guitar is isolated and has absolutely no contact
with the mechanical device, except when the plectrum plucks the tested string.