JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 39

The sound of composite violins investigated

liked when played by the second
player. Listeners' evaluations can be
influenced by the performer's way
of playing the instrument. In our
evaluation experiment, this violin's
sound color was described as harsh.
This is less clear in our selection experiment, as the nature of this experiment emphasizes the positive
qualities of each instrument.
UDC, with a higher anisotropy
than TwillCA and TwillCB, was described as round and soft and was
chosen less as powerful. This could
be an indicator that for composite
materials, a higher degree of anisotropy results in an instrument with a
round and soft tonal color preferred
by many listeners, but with a less
powerful sound. More research is
definitely needed to investigate this
aspect and correlate it with numerical predictions.
In our evaluation experiment, two
violins were preferred more than
others. One had a soundboard from
a laminate of unidirectional and
woven carbon (TwillCB), the other
was made from unidirectional flax
(UDFlax). Although UDFlax had
the least powerful sound among our
prototypes, its sound color being
described as warm, soft and round
still made it a favorite for many listeners. The other favorite instrument TwillCB had a sound color
described as warm and rich. In our
selection experiment, TwillCB was
favored over UDFlax by the listeners with both players. The listener's
preference in our experiments seem
mostly guided by sound color, and
less by projection or loudness of the
instruments. However, when both
instruments have a favorable sound
color, the instrument with the better
projection was favored between the
two most preferred violins. In both
experiments, listeners indicated to
find a warm sound an important
quality parameter, followed by adjectives such as clear, open, round

Fig. 7: Percentage distribution on the description
of the favored sound color
for each of the violins

and rich.
The instruments presented in this
study differ from a classic violin
in a number of ways, therefore we
cannot directly extrapolate the results from our violin with a spruce
soundboard to that of wooden violins in general. We can only say that
between our prototypes, the violin
with a spruce soundboard was not
favored over the full-composite
violins and did not stand out in a
particular way with regard to tonal
color or projection. Future research
has to be performed in order to allow for more direct comparisons between instruments with composite
top plates and truly conventional,
wooden violins.
An alternative road future studies
and artists could take is to investigate the full-composite instruments
as a class of sound-generators of
their own, with their own sonic
possibilities, and be less concerned
about a comparison with their conventional counterparts.
Conclusion
Contrary to popular opinion among
violin players, there is no specific
sound property or quality that we
can assign to the material group of
fiber reinforced composites. As a
consequence no generalizations like
'the sound of carbon violins lack
warmth' hold in our experiments.
Composite materials allow to create violins with a large diversity in
sounds and therefore offer possibilities to change the sound to the

criteria of the player. In theory, by
only varying the material and layup of the soundboard, the sound
of a violin could be changed to fit
the requirements of the player. Our
results follow the logic that soundboards which are more lightweight
and have a lower anisotropy are
more efficient sound radiators than
heavier soundboards with a higher
anisotropy.
Although all our participants can
be considered experienced listeners, individuals prefer different violin-like sounds.
Depending on which violin player is
playing, the preference of the listener can shift between instruments.
Although the sound of some violins
was favored more than others, there
was no such thing as the 'best' violin
sound overall.
This research provides insight in
how violins with soundboards from
different composites can sound, the
possible advantages these materials
can offer in relation to the sound
they produce as a soundboard for
violins, and which of these violins
were favored by listeners. However,
composite materials offer a great
diversity of fibers, polymer matrix
and core materials that must still be
examined. While the craftsmanship
of making good wooden violins has
evolved over centuries, resulting in
an optimization of the realization of
the material's potential. Composite
instruments are very new and may
require a new kind of craftsmanship

SPECIAL ISSUE Sports, Health & Leisure / November 2020 /

jec composites magazine

39



JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020

Cover
Edito
Contents
TRENDS
Business - Sports and health: a wealth of opportunities for composites
e-Bike - Uncertainties over Chinese supply chains put pressure on electric bike producers
Opportunities - The Gaming industry asks composites players: are you ready?
PROCESSING
Characterization - Bamboo versus maple from a skateboard manufacturer’s viewpoint
Engineering lntegrated loop technology provides new high strength joints for carbon fibre composites
Additive manufacturing - Disrupting the composite tooling supply chain
Biocomposites - Changing the outdoor hardware industry
APPLICATION
Climbing - A mountain in the middle of the city
Acoustic - The sound of composite violins investigated
Loudspeakers - Best sound in the world
Jewellery - Shine bright like a composite
Travel - Carbon fibre composites give luggage a leg up
Watersports - Closed-loop recycling of epoxy composites
Running shoes - Composites make their own mark in China
Sprinting shoes - Future of sprinting: spikeless CFRTP sprinting shoe
Medical - Advanced composite materials for prosthetic sockets in developing countries
Prostheses - A new way to make prostheses and orthoses
Paralympics - ‘‘The company’s objective is to design a future full of choices”
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Cover
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 2
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Edito
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 4
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 5
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Contents
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Business - Sports and health: a wealth of opportunities for composites
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 8
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 9
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 10
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - e-Bike - Uncertainties over Chinese supply chains put pressure on electric bike producers
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 12
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 13
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Opportunities - The Gaming industry asks composites players: are you ready?
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 15
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 16
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 17
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 18
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 19
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 20
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Characterization - Bamboo versus maple from a skateboard manufacturer’s viewpoint
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 22
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Engineering lntegrated loop technology provides new high strength joints for carbon fibre composites
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 24
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 25
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 26
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Additive manufacturing - Disrupting the composite tooling supply chain
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 28
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 29
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Biocomposites - Changing the outdoor hardware industry
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 31
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Climbing - A mountain in the middle of the city
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 33
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Acoustic - The sound of composite violins investigated
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 35
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 36
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 37
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 38
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 39
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 40
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Loudspeakers - Best sound in the world
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 42
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Jewellery - Shine bright like a composite
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 44
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Travel - Carbon fibre composites give luggage a leg up
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 46
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Watersports - Closed-loop recycling of epoxy composites
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 48
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 49
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Running shoes - Composites make their own mark in China
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 51
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Sprinting shoes - Future of sprinting: spikeless CFRTP sprinting shoe
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 53
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 54
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Medical - Advanced composite materials for prosthetic sockets in developing countries
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 56
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 57
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 58
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 59
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 60
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 61
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Prostheses - A new way to make prostheses and orthoses
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 63
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - Paralympics - ‘‘The company’s objective is to design a future full of choices”
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 65
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 66
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 67
JEC COMPOSITES MAGAZINE - Special Issue Composites for Sports, Health & Leisure - November 2020 - 68
https://www.nxtbook.fr/newpress/jeccomposites/jcm2201_144
https://www.nxtbook.fr/newpress/jeccomposites/jcm211_143
https://www.nxtbook.fr/newpress/jeccomposites/jcm2109_142
https://www.nxtbook.fr/newpress/jeccomposites/jcm2107_141
https://www.nxtbook.fr/newpress/jeccomposites/jcm2105_140
https://www.nxtbook.fr/newpress/jeccomposites/jcm2103_139
https://www.nxtbook.fr/newpress/jeccomposites/jcm-experts-digest-additive-manufacturing-2020
https://www.nxtbook.fr/newpress/jeccomposites/jcm2101_138
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_Special_Issue4
https://www.nxtbook.fr/newpress/jeccomposites/jcm2011_137
https://www.nxtbook.fr/newpress/jeccomposites/jcm2009_136
https://www.nxtbook.fr/newpress/jeccomposites/jcm2007_135
https://www.nxtbook.fr/newpress/jeccomposites/jcm_2020_Q1_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_Special_Issue3
https://www.nxtbook.fr/newpress/jeccomposites/jcm2005_134
https://www.nxtbook.fr/newpress/jeccomposites/jcm2003_133
https://www.nxtbook.fr/newpress/jeccomposites/jcm2001_132
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_Special_Issue2
https://www.nxtbook.fr/newpress/jeccomposites/jcm1911_131
https://www.nxtbook.fr/newpress/jeccomposites/jcm1909_130
https://www.nxtbook.fr/newpress/jeccomposites/jcm1907_129
https://www.nxtbook.fr/newpress/jeccomposites/jcm1905_128
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_Special_Issue1
https://www.nxtbook.fr/newpress/jeccomposites/jcm1903_127
https://www.nxtbook.fr/newpress/jeccomposites/jcm1901_126
https://www.nxtbook.fr/newpress/jeccomposites/jcm1811_125
https://www.nxtbook.fr/newpress/jeccomposites/jcm1810_124
https://www.nxtbook.fr/newpress/jeccomposites/jcm1808_123
https://www.nxtbook.fr/newpress/jeccomposites/jcm1807_122
https://www.nxtbook.fr/newpress/jeccomposites/jcm1805_121
https://www.nxtbook.fr/newpress/jeccomposites/jcm1804_120
https://www.nxtbook.fr/newpress/jeccomposites/jcm1803_119
https://www.nxtbook.fr/newpress/jeccomposites/jcm1802_119-Supplement_Innovation_Report
https://www.nxtbook.fr/newpress/jeccomposites/jcm1801_118
https://www.nxtbook.fr/newpress/jeccomposites/jcm1711_117
https://www.nxtbook.fr/newpress/jeccomposites/jcm1710_116
https://www.nxtbook.fr/newpress/jeccomposites/jcm1708_115
https://www.nxtbook.fr/newpress/jeccomposites/jcm1707_114
https://www.nxtbook.fr/newpress/jeccomposites/jcm1706_113
https://www.nxtbook.fr/newpress/jeccomposites/jcm1704_112
https://www.nxtbook.fr/newpress/jeccomposites/jcm1703_111
https://www.nxtbook.fr/newpress/jeccomposites/jcm1701_110
https://www.nxtbook.fr/newpress/jeccomposites/jcm1611_109
https://www.nxtbook.fr/newpress/jeccomposites/jcm1610_108
https://www.nxtbook.fr/newpress/jeccomposites/jcm1608_107
https://www.nxtbook.fr/newpress/jeccomposites/jcm1607_106
https://www.nxtbook.fr/newpress/jeccomposites/jcm1605_105
https://www.nxtbook.fr/newpress/jeccomposites/jcm1604_104
https://www.nxtbook.fr/newpress/jeccomposites/jcm1603_103
https://www.nxtbook.fr/newpress/jeccomposites/jcm1601_102
https://www.nxtbook.fr/newpress/jeccomposites/jcm1511_101
https://www.nxtbook.fr/newpress/jeccomposites/jcm1510_100
https://www.nxtbook.fr/newpress/jeccomposites/jcm1509_99
https://www.nxtbook.fr/newpress/jeccomposites/jcm1507_98
https://www.nxtbook.fr/newpress/jeccomposites/jcm1505_97
https://www.nxtbook.fr/newpress/jeccomposites/jcm1504_96
https://www.nxtbook.com/newpress/jeccomposites/jcm1503_95
https://www.nxtbook.com/newpress/jeccomposites/jcm1501_94
https://www.nxtbook.com/newpress/jeccomposites/jcm1412_93
https://www.nxtbook.com/newpress/jeccomposites/jcm1410_92
https://www.nxtbook.com/newpress/jeccomposites/jcm1409_91
https://www.nxtbook.com/newpress/jeccomposites/jcm1406_90
https://www.nxtbook.com/newpress/jeccomposites/jcm1405_89
https://www.nxtbook.com/newpress/jeccomposites/jcm1404_88
https://www.nxtbook.com/newpress/jeccomposites/jcm1403_87
https://www.nxtbook.com/newpress/jeccomposites/jcm1401_86
https://www.nxtbook.com/newpress/jeccomposites/jcm1311_85
https://www.nxtbook.com/newpress/jeccomposites/jcm1310_84
https://www.nxtbook.com/newpress/jeccomposites/jcm1308_83
https://www.nxtbook.com/newpress/jeccomposites/jcm1307_82
https://www.nxtbook.com/newpress/jeccomposites/jcm1305_81
https://www.nxtbook.com/newpress/jeccomposites/jcm1304_80
https://www.nxtbook.com/newpress/jeccomposites/jcm1303_79
https://www.nxtbook.com/newpress/jeccomposites/jcm1301_78
https://www.nxtbook.com/newpress/jeccomposites/jcm1212_77
https://www.nxtbook.com/newpress/jeccomposites/jcm1210_76
https://www.nxtbook.com/newpress/jeccomposites/jcm1208_75
https://www.nxtbook.com/newpress/jeccomposites/jcm1207_74
https://www.nxtbook.com/newpress/jeccomposites/jcm1206_73
https://www.nxtbook.com/newpress/jeccomposites/jcm1204_72
https://www.nxtbook.com/newpress/jeccomposites/jcm1203_71
https://www.nxtbook.com/newpress/jeccomposites/jcm1201_70
https://www.nxtbook.com/newpress/jeccomposites/jcm1111_69
https://www.nxtbook.com/newpress/jeccomposites/jcm1110_68
https://www.nxtbook.com/newpress/jeccomposites/jcm1108_67
https://www.nxtbook.com/newpress/jeccomposites/jcm1107_66
https://www.nxtbook.com/newpress/jeccomposites/jcm1105_65
https://www.nxtbook.com/newpress/jeccomposites/jcm1104_64
https://www.nxtbook.com/newpress/jeccomposites/jcm1103_63
https://www.nxtbook.com/newpress/jeccomposites/jcm1101_62
https://www.nxtbook.com/newpress/jeccomposites/jcm1011_61
https://www.nxtbook.com/newpress/jeccomposites/jcm1010_60
https://www.nxtbook.com/newpress/jeccomposites/jcm1009_59
https://www.nxtbook.com/newpress/jeccomposites/jcm1006_58
https://www.nxtbook.com/newpress/jeccomposites/jcm1005_57
https://www.nxtbook.com/newpress/jeccomposites/jcm1004_56
https://www.nxtbook.com/newpress/jeccomposites/jcm1003_55
https://www.nxtbook.com/newpress/jeccomposites/jcm1001_54
https://www.nxtbook.com/newpress/jeccomposites/jcm0911_53
https://www.nxtbook.com/newpress/jeccomposites/jcm0910_52
https://www.nxtbook.com/newpress/jeccomposites/jcm0909_51
https://www.nxtbook.com/newpress/jeccomposites/jcm0907-08_50
https://www.nxtbook.com/newpress/jeccomposites/jcm0906_49
https://www.nxtbook.com/newpress/jeccomposites/jcm0904_48
https://www.nxtbook.com/newpress/jeccomposites/jcm0903_47
https://www.nxtbook.com/newpress/jeccomposites/jcm0901_46
https://www.nxtbook.com/newpress/jeccomposites/jcm0811_45
https://www.nxtbook.com/newpress/jeccomposites/jcm0810_44
https://www.nxtbook.com/newpress/jeccomposites/jcm0809_43
https://www.nxtbook.com/newpress/jeccomposites/jcm0807_42
https://www.nxtbook.com/newpress/jeccomposites/jcm0806_41
https://www.nxtbook.com/newpress/jeccomposites/jcm0805_40
https://www.nxtbook.com/newpress/jeccomposites/jcm0803_39
https://www.nxtbook.com/newpress/jeccomposites/jcm0801_38
https://www.nxtbook.com/newpress/jeccomposites/jcm0712_37
https://www.nxtbook.com/newpress/jeccomposites/jcm0710_36
https://www.nxtbook.com/newpress/jeccomposites/jcm0709_35
https://www.nxtbook.com/newpress/jeccomposites/jcm0707_34
https://www.nxtbook.com/newpress/jeccomposites/jcm0706_33
https://www.nxtbookmedia.com