THE SONG OF GLASSES LAIN - UMR CNRS 5011 Univ. Montpellier 2 - cc 82 34095 MONTPELLIER cedex 5...
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THE SONG OF GLASSES THE SONG OF GLASSES LAIN - UMR CNRS 5011 Univ. Montpellier 2 - cc 82 34095 MONTPELLIER cedex 5 FRANCE Ing. Jean-Yves Ferrandis Pr. Gerard Leveque Pr. Jacques Attal
THE SONG OF GLASSES LAIN - UMR CNRS 5011 Univ. Montpellier 2 - cc 82 34095 MONTPELLIER cedex 5 FRANCE Ing. Jean-Yves Ferrandis Pr. Gerard Leveque Pr. Jacques
THE SONG OF GLASSES LAIN - UMR CNRS 5011 Univ. Montpellier 2 -
cc 82 34095 MONTPELLIER cedex 5 FRANCE Ing. Jean-Yves Ferrandis Pr.
Gerard Leveque Pr. Jacques Attal
Slide 2
GOAL: STUDY OF THE HARMONY OF GLASSES n GOAL: STUDY OF THE
HARMONY OF GLASSES Acoustical criteria the strike note : pitch and
sound decay timbre consonance and dissonance Subjective
approach
Slide 3
n I. Sound analysis : theoretical background n II. Experiences
on glasses and crystal glasses n III. Discussion n IV. Test of
listening n V. Conclusions FRAME WORK
Slide 4
n Harmonic partials : string instruments n Inharmonic partials
: infinite cylindrical pipes n Spectral analysis n Circular plates
n Vibration of bells n Consonance intervals I. Sound analysis :
theoreticalbackgrond
Slide 5
Harmonic partials : string instruments n String equation
Solutions density S cross-area T strain force n order of the mode
frequency n = 1, 2, 3, 4 . z TTx
Slide 6
Inharmonic partials : infinite cylindrical pipes n Infinite
cylindrical pipes z : axis of the pipe : angle in the shear cut e :
thickness of the pipe e, : Young modulus, Poisson coefficient R :
radius of the pipe : density The partial mode are not harmonic
frequency intervals [1, 8/3, 5, 8, 35/3 ]
Slide 7
1234567 8 Cylinders Fondamental frequency m=2m=3 m = 1 m = 2
Spectral analysis m=4m=5 String vibrations 8/3
Slide 8
Circular plates Chladni s law (empirical relation ship) where c
is the sound velocity (n,m) is the mode numbers for flat plates p =
2 for non flat plates (cymbals, bells) p < 2
Slide 9
Vibration of bells n The bells can be tuned on harmonic
partials
Slide 10
Consonance intervals for bells
Slide 11
n Pitch n Sound decay n Warble II. Experiences on glasses and
crystal glasses
Slide 12
Sound analysis : Typical response
Slide 13
: Time constant for a decay 0.368 Sound decay
Slide 14
Beats due to a dissimetry of the sample B A B A B A BWarble Tea
cup
Slide 15
n Shape n Materials n Manufacturing III. Discussion : Effects
of
Slide 16
Shape dependance The thicker the glass the higher the pitch f 2
/f 1 = 2.35 (tenth = 2.4 ) can be adjusted from 2 to 2.5 according
to ellipticity f 2 /f 1 = 1.48f 3 /f 1 = 2.01 (quint = 1.5) can be
adjusted with the opening angle ELLIPTICAL CONICAL
Slide 17
Materials dependance The time constant of the decay is four
times as large for the crystal glass with same shape. The pitch and
the timbre are correctly appreciated when the decay is small. Verre
blancCristal
Slide 18
Spreading of the measurements (fundamental and first harmonic)
Repeatability on a serial of identical glasses Manufacturing
Slide 19
Test procedure n Collect opinion from an audience of 25 people
n Listening to synthetic sounds which simulates glass strikes :
effect of pitch, timbre, time decay... u Note : This test has been
performed on non informed audience, but is dependant on the musical
background of each one IV. Test of listeing
Slide 20
V. Test and results Q : PITCH EFFECT : thickness and shapeA1B1
A : Preference for bass tones Q : TIME DECAYA2B2 A : Large
agreement for long decay : crystal glass is unanimously appreciated
Q : RATIO f 2 /f 1 A4B4B5B6 A : Audience can make difference
between consonance and dissonance but does not agree on the
appreciation Q : NUMBER OF PARTIALSA7B7 A : Slight preference for
few partials
Slide 21
F PSYCHOLOGICAL IMPACT OF THE SONG OF THE GLASS PITCH TIMBRE
TIME DECAY F MANUFACTURING QUALITY CONTROL F NEW DESIGN OF GLASS
CONSONANT SERIALS NEW SHAPES WHICH ENHANCE SPECIFIC MODES
Conclusions