Estimating blade stiffness through sound recording
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Topic: Estimating blade stiffness through sound recording
Posted By: arg0
Subject: Estimating blade stiffness through sound recording
Date Posted: 12/02/2010 at 5:30pm
Hi all, to avoid off-topics in the OSPblades Forum Testing thread, I'm opening a new thread.
Without
going into complex mechanical considerations like it has been done in other threads, a
simple way to estimate the hardness stiffness vibration frequency of the membrane mode (see http://mytabletennis.net/forum/forum_posts.asp?TID=79533&PID=986498&title=expressing-relative-blade-speed#986498" rel="nofollow - this post for indication of what this represents) of a blade is to record the sound of a ball dropped on the center of the
blade, while the handle is held lightly with one hand, and then looking
at the highest peak of the spectrum of the recorded sound.
It goes like this (see also the attached images): 1. download and install Audacity from http://audacity.sourceforge.net/ 2. Launch Audacity, press the record button. 3. Put the bat horizontally close to the microphone, holding it lightly with one hand. 4. Let a table tennis ball drop a few times on the bat from about 10-15 cm (4-6 in) height. 5. Stop recording. 6. Select Menu Analyze -> Plot Spectrum 7. Find the frequency of the highest peak in the spectrum and report it
This is Audacity showing the record button and an already recorded sound:
This is the Plot Spectrum option:
This
is the spectrum: move the mouse (crosshair cursor) vertically close to
the highest peak and read the corresponding frequency of the peak
(highlighted in red):
It's really simple and requires no longer than 2 minutes. (For the more technically minded, I know, this gives info only on one
vibration mode, but it's nevertheless an easy way to estimate hardness stiffness...)
In a next post, I am going to attach a table with the frequency of quite some blades. It would be great if you could post your measurements, so I can add them to the table. I'm especially interested in new blades that are not already in the table.
EDIT: changed stiffness to hardness, thanks davidz for pointing this out. EDIT: replaced hardness with stiffness after pnachtwey's post EDIT: replaced stiffness with vibration frequency of membrane mode and provided a link to further information
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Replies:
Posted By: arg0
Date Posted: 12/02/2010 at 5:42pm
This is the table: uploads/20417/Blade_frequencies_Nov-2010.xls - uploads/20417/Blade_frequencies_Nov-2010.xls
I contribute to keep it updated in the tt-news.de forum, that's why the notes are in German (I only translated the headers).
Short word list: lackiert, versiegelt: varnished gerade: straight dick: thick gekürzt, geschliffen: shortened
Enjoy!
------------- Nexy Arche & Nittaku Violin LG. Join the forum_posts.asp?TID=47778" rel="nofollow - Nexy Clan ! Also member of Violin & 1-Ply clans.
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Posted By: davidz
Date Posted: 12/02/2010 at 5:52pm
A list of the blade's sound frequency could be very useful. Thanks!
I used the same software check the blade's spectrum with/without rubber. It helps tuning a rubber and modifying the size of my blade.
Blade frequency is just one characteristic, which tends to measure the hardness of the blade. Another characteristic is amplitude of the blade's virbration, which is related to blade's stiffness. Unfortunately, this could not be measured using software.
One thing
------------- PG7 (Skyline 2, LKT XP)
YEO (Skyline 2, Skyline 3)
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Posted By: pnachtwey
Date Posted: 12/02/2010 at 5:59pm
Good stuff, how about the decay? I have a 729 bomb that almost sounds like a musical instrument when hit. The 929 Bomb sound is clear and not muffled. I also have an LKT Instinct blade that is lower pitched but with an shorter/muffled sound. A clearer longer sound indicated that the wood is not damped and doesn't lose energy quickly as a blade with a shorter muffled sound and more damping. A blade with more damping would not return as much energy to the ball.
I also have wondered if the higher frequencies help. For instance if the ball has a dwell time of 2-4 milliseconds wouldn't it be best if the frequency of the paddle was lower than 1328 Hz and closer to having a period twice the dwell time of the ball on the paddle? If the paddle pushes back mach faster than the rubber then the ball will separate from the rubber on the rebound before the rubber has had a chance to return most if its energy to the ball.
I do think that Arg0 has hit on something important. I think there is a best frequency for the primary mode. Everyone knows that pushing a child on a swing at the wrong rate is inefficient.
------------- I TT therefore I am
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Posted By: Vladovich
Date Posted: 12/02/2010 at 6:09pm
Does this measurement depends on the quality of our microphone? Can the microphone itself cut of some high frequencies?
------------- Tibhar Defense Plus
FH: Joola Phenix
BH: Dr. Neubauer Bison 1.5mm
"The dark side of the Force is a pathway to many abilities, some consider to be…unnatural."
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Posted By: Best99
Date Posted: 12/02/2010 at 8:13pm
Of course it can. If you would like to record precisely all the frequencies, you would have to use a professional microphone (available on music studios, for example).
------------- Blade: Timo Boll ALC 92 g.
Forehand: Tenergy 05 2.1 mm. (black)
Backhand: Tenergy 05 2.1 mm. (red).
Perfect loops
|
Posted By: Pioneer
Date Posted: 12/02/2010 at 8:25pm
Doesn't rubber's density count here as a major factor ?
------------- Blade: Timo Boll ZLF ST http://mytabletennis.net/forum/topic71344_post873640.html#873640" rel="nofollow - My Feedback
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Posted By: pnachtwey
Date Posted: 12/02/2010 at 8:32pm
A good microphone doesn't need to cost a lot. I have one of these http://pro-audio.musiciansfriend.com/product/Blue-Snowball-USB-Microphone?sku=279015 Oops, that is more than a sheet of T05. I have one of these and the quality is pretty good for the price. The frequency range far exceeds what is required for testing blades audio responses.
------------- I TT therefore I am
|
Posted By: Best99
Date Posted: 12/02/2010 at 8:41pm
Ok, but anyway, who is going to spend about 100 dollars just to buy a microphone to see how fast/stiff is a blade :P?
------------- Blade: Timo Boll ALC 92 g.
Forehand: Tenergy 05 2.1 mm. (black)
Backhand: Tenergy 05 2.1 mm. (red).
Perfect loops
|
Posted By: arg0
Date Posted: 12/03/2010 at 2:18am
I think the measurements should be quite consistent across user
settings, because the spectrum does not depend (much) on intensity and
microphone sensitivity (also a cheap laptop microphone should be sufficiently linear
in that range). There is some dependency on other factors, too, e.g. how firmly you hold the blade etc. Some time ago I have tried with my crappy laptop microphone and, some time later, with a better one and the difference I got was compatible with variations due to other factors (about 20-30 Hz if I remember well). So there's no need to buy expensive equipment (microphones and tenergys ;-) ).
These numbers should not be read as exact values, but as approximations to about 50 Hz. I
mean, a difference of 30 Hz is quite negligible and may depend on
setup, a difference of 100 Hz is surely due to the blade
characteristics.
@Pioneer, I'm testing only the blade, there's no rubbers on it.
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Posted By: vvu.tee
Date Posted: 12/03/2010 at 2:43am
thanks arg0, really useful info, I've got
2-3 Korbels FL, I will test it on next weekend - that will be fun...
what is the relation between the stiffness and the peak sound/vibration.
also, how would you differentiate between the effects on vibration by
the stiffness (elasticity) and hardness (plasticity).
btw,
non-destructive testing is not really my cup of tea, but what do you
thing, can you extend the test to compare stiffness of different
designs/wood types, i.e totally different blades, or just test for
variation within the same model?
some engineering insight will be helpful...?
------------- (1) BTY T64 - BTY M.MAZE - BTY T05
(2) BTY T64 - BTY M.MAZE - DHS H3 Neo Provincial
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Posted By: arg0
Date Posted: 12/03/2010 at 4:48pm
One day I will dig into the physics of table tennis, but for now I will just limit myself to empirical considerations: with a ball bounce test, the ball has not much energy, so the bat only undergoes tiny elastic deformations. What is not true is that in this case only the outer layer contributes: otherwise, say, all hinoki blade would have similar frequencies, which is definitively not the case.
PS: for in-depth discussions about the mechanics involved, see these threads: http://mytabletennis.net/forum/forum_posts.asp?TID=26762 - http://mytabletennis.net/forum/forum_posts.asp?TID=26762 http://www.tabletennisforum.gr/forum_posts.asp?TID=11262 - http://www.tabletennisforum.gr/forum_posts.asp?TID=11262 I prefer to keep it simple here. However, if you spot something there that can contribute to this discussion, please post it.
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Posted By: atv
Date Posted: 12/05/2011 at 9:52pm
Digging this thread out from reading arg0's post in Calix review, interesting method, i want to use it on a table our club recently purchased, I found this table biting off significant speed and spin from the ball but have no objective evidence, my friend has a set of professional piano calibration devices i could borrow.
So the harder a surface is the higher pitch it will provide? Will it also apply to something as big as a table?
------------- YEO
FH: 729 08 ES
BH: Focus III Snipe
Senkoh-1
FH: H3 Comm
BH: 755
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Posted By: arg0
Date Posted: 12/06/2011 at 1:50am
In principle, yes, although I'm no material science specialist and one year later I still haven't had the time to read the technical posts I referred to. What is clear is that with tiny ball bounces as I used to make for measurements, one tests the blade's response at slow speeds. However, not only the outer layers are involved, because I tested several wood with kiso hinoki outer layers and got frequencies from 1300 to 1800 Hz. I wish I had a way to launch balls at a predetermined speed to see if the first resonance frequency changes at higher speeds. Maybe for a first test I could simply block the blade handle between books and manually throw balls at it. Speed won't be consistent but at least I'll be able to see if there's a frequency shift.
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Posted By: pnachtwey
Date Posted: 12/06/2011 at 1:08pm
I am bothered about the assertion that blade hardness is determined by frequency.
I like to do my absurdity tests and if the assertion can't pass that then the assertion is wrong or there is more to it than what is stated.
So why do marimba keys sound different if they are made of the same kind of wood? The answer is size not hardness. Now I do believe that if one were to try to bend a larger marimba key it would flex more than a shorter one.
So why was stiffness replaced by hardness?
Arg0, an object will vibrate at its natural frequency but that can be changed by damping. Rubbers are good dampers and will reduce the frequency of oscillation
http://en.wikipedia.org/wiki/Damping
Anther thing I find interesting is that the period of oscillation is much shorter than the dwell time. This would mean the blade would oscillate a cycle to two times while the ball is in contact with the rubber. That would be like push a child on a swing at a rate faster than the natural frequency. I would test this out on a hard bat or even a bare wood slow paddle.
%20 - %20 -
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Posted By: arg0
Date Posted: 12/06/2011 at 5:14pm
You've got a point there, so I put stiffness back. Actually I believe is that what I am measuring is frequency of the fundamental bending mode of the blade, which is fixed at one end (the handle). So it is rather related to flexibility, rather than hardness.
I have not considered rubbers, as blades alone are already complex enough for me to understand.
Do you have any estimate on how much dwell time is in table tennis shots?
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Posted By: pnachtwey
Date Posted: 12/06/2011 at 6:16pm
arg0 wrote:
Do you have any estimate on how much dwell time is in table tennis shots? |
1 millisecond seems a like a reasonable number. If the ball spends half of its time decelerating and have accelerating again then the deceleration time would be about 0.5 seconds. If we assume the paddle to be stopped and the ball is hitting the paddle at 10 m/s the average speed during decal will be 5 m/s. Multiply this by 0.5 milliseconds and the result is 2.5mm deceleration distance. This means the ball deforms, the rubber deforms and the blade deforms about 2.5 mm during the impact and this is not a fast impact. If the dwell time were longer the deformation would need to be proportionately greater.
It seems to me that a blade that vibrates too fast would vibrate out of phase.
I should do a simulation with two springs and make one spring much stiffer than the other just to see what would happen.
I know a TT ball will deform a lot. I wish I had a good high speed camera. Not the 500 Casio toys. I mean a good 10,000 FPS camera. It is only $100K. If any body chips in I may buy one just to answer these questions.
BTW, what do you think the average force between the paddle and the ball during impact if the relative speed is 10 m/s? It isn't hard to calculate but you have to assume a dwell time that makes sense. Assume 1 millisecond.
I am amused at those that talk about extra dwell time on the paddle. The differences can probably be measured in microseconds.
------------- I TT therefore I am
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Posted By: arg0
Date Posted: 06/30/2017 at 6:11pm
I've decided to contribute the data that I've collected. The majority of
data comes from the table in the German forum I mentioned above. I
have added the data for all the blades that I've measured over the last
years. Enjoy!
If you have measured frequencies for any blade not on the
list, or found frequencies that significantly differ from the ones
listed, please report.
Brand |
Model |
Handle |
Weight (g) |
Frequency (Hz) |
Donic |
Defplay Senso |
|
|
829 |
Nittaku |
Miyabi |
FL |
83 |
864 and 1218 |
American Hinoki |
Ancient Kauri |
ST |
93 |
906 and 1233 |
W. Froese |
Def/All |
|
|
976 |
Donic |
Defplay Senso konkav |
|
83 |
977 |
Joola |
Rossi Fire |
|
|
1006 |
Stiga |
Anniversary LE2092 |
|
|
1017 |
Stiga |
Allround Stellan Bengtson |
ST |
|
1024 |
Joola |
Allround |
|
83 |
1039 |
Joola |
Play-OFF |
|
|
1041 |
Stiga |
Alser 69 |
|
96 |
1050 |
LKT |
Toxic3 |
|
|
1059 |
Nittaku |
Violin |
|
86 |
1059 |
Weltklasse |
Prestige Carbon |
|
|
1063 |
Stiga |
Energy Wood |
|
86 |
1068 |
Butterfly |
Timo Boll All+ |
|
|
1078 |
Double Fish |
167 |
FL |
|
1083 |
Imperial |
Eberhard Schöler |
ST |
97 |
1087 |
Butterfly |
Secretin ALL |
|
|
1088 |
Butterfly |
Korbel Japan |
|
|
1091 |
Butterfly |
Primo Japan |
|
80 |
1091 |
Stiga |
Allround Classic |
|
|
1092 |
Stiga |
Allround Ulf Tickan Carlsson |
|
|
1096 |
Stiga |
Jubi LE1054 |
|
85 |
1096 |
Gewo |
Super Control |
|
|
1099 |
Donic |
Epox Control |
|
80 |
1100 |
Stiga |
Offensive Classic |
|
|
1100 |
Butterfly |
Grubba all+ |
ST |
80 |
1101 |
Butterfly |
Grubba ALL+ |
|
80 |
1101 |
Butterfly |
Boll Forte |
|
90 |
1105 |
Donic |
Appelgren Falcon |
|
75 |
1105 |
Stiga |
Offensive Classic CR |
|
|
1107 |
Imperial |
Sensor |
|
91 |
1108 |
Butterfly |
Maze Passion |
|
93 |
1109 |
Stiga |
Def Wood C-Serie |
|
77 |
1110 |
Nittaku |
Vioncello |
ST |
|
1115 |
Stiga |
Jubi LE Serie |
|
85 |
1123 |
Butterfly |
Tempest |
|
80 |
1132 |
Yinhe |
W-6 |
|
92 |
1135 |
Banda |
Century 5 |
|
88 |
1138 |
Banda |
Scandik WRB |
|
76 |
1140 |
Butterfly |
Primorac Japan ohne Seriennummer |
|
|
1141 |
Stiga |
Anniversary D202 |
|
|
1145 |
BBC |
Fiddler |
CO |
80 |
1146 |
Butterfly |
Primorac Classic |
|
|
1146 |
Stiga |
Allround Hans Alser 1983 |
|
|
1148 |
Stiga |
alte dicke Hölzer |
|
|
1150 |
Donic |
Allplay alt (weiße Linse) |
|
86 |
1156 |
Joola |
Rosskopf Fire |
|
78 |
1156 |
Stiga |
Tube Allround |
|
88 |
1156 |
Avalox |
BT 550 |
|
|
1158 |
Butterfly |
Boll Spark |
ST |
89 |
1160 |
Butterfly |
Boll Spark |
|
89 |
1160 |
Stiga |
Offensive CR |
|
81 |
1160 |
Nittaku |
Violin |
FL |
80 |
1161 |
OSP |
Expert |
SQST |
87.5 |
1161 |
Butterfly |
Boll Spark |
ST |
83 |
1162 |
Butterfly |
Boll Spark |
|
83 |
1162 |
Stiga |
Offensive CR |
|
79 |
1163 |
Schöler-Micke |
Allround+ |
|
|
1164 |
Butterfly |
Primo Classic |
|
|
1166 |
Donic |
Appelgren Allplay |
|
85 |
1167 |
Joola |
Sting |
|
100 |
1168 |
Butterfly |
Guo Yue Japan |
|
|
1170 |
Nittaku |
Violin |
ST |
87 |
1170 |
Stiga |
Alser All C-Serie |
|
92 |
1170 |
Nittaku |
Violin L-Size |
ST |
85 |
1178 |
Stiga |
Energy Wood |
|
|
1178 |
Stiga |
Off Classic |
|
75 |
1178 |
Avalox |
Blue Thunder 550A |
|
|
1180 |
Nittaku |
Violin L-Size |
ST |
86 |
1180 |
Nittaku |
Violin L-Size |
ST |
88 |
1180 |
TSP |
Black Blizzard |
|
|
1180 |
TSP |
Black Blizzard Carbon Off |
|
|
1180 |
Yinhe |
EC-13 |
|
88 |
1180 |
NEXY |
Lissom |
ST |
83 |
1181 |
Avalox |
P500 |
|
|
1183 |
OSP |
Expert |
SQST |
88 |
1183 |
Schildkröt |
Futec |
|
|
1183 |
Butterfly |
Chuan Chih-Yuan |
ST |
86 |
1184 |
NEXY |
Higgs |
ST |
|
1184 |
Stiga |
Graphite Wood |
|
94 |
1185 |
Butterfly |
Primorac Japan AN |
|
87 |
1188 |
Donic |
Persson Powerplay |
|
|
1188 |
Butterfly |
Chuan Chih-Yuan |
|
86 |
1189 |
Nimatsu |
Celsior 5.6 Direct |
ST |
79 |
1189 |
Stiga |
Offensive CR |
|
|
1189 |
Butterfly |
Schlager Inspire |
|
96 |
1190 |
Nimatsu |
Celsior 5.6 Direct |
ST |
77 |
1190 |
NEXY |
Lissom Special |
ST |
85 |
1193 |
Stiga |
Off Classic |
|
85 |
1194 |
Stiga |
Energy Wood WRB |
FL |
81 |
1199 |
Stiga |
Energy Wood WRB |
|
81 |
1199 |
Donic |
Waldner Senso Carbon |
|
|
1200 |
OSP |
Ultimate |
RST |
93 |
1200 |
Yinhe |
LQ-1 |
|
91 |
1200 |
Yinhe |
MC-3 |
|
88 |
1200 |
Butterfly |
Maze Passion |
|
|
1201 |
Imperial |
Eberhard Schöler |
ST |
102 |
1202 |
Butterfly |
Korbel deutsch |
|
|
1204 |
Donic |
Waldner Senso Carbon |
|
84 |
1204 |
Tibhar |
Black Silver |
|
88 |
1204 |
Butterfly |
Kenny Style |
ST |
91 |
1206 |
NEXY |
Lissom |
ST |
84 |
1206 |
Juic |
Kalinic |
|
|
1207 |
Butterfly |
Adolescen |
|
|
1209 |
Donic |
Epox Powerallround |
|
|
1209 |
Butterfly |
Boll Off- |
|
|
1210 |
Nittaku |
Acoustic |
|
89 |
1210 |
Donic |
Persson Power Play V2 |
|
84 |
1211 |
Ross Leidy |
Vagabond |
AN |
88 |
1211 |
Nimatsu |
Celsior 5.6 Direct |
ST |
77 |
1215 |
Yinhe |
980 |
|
89 |
1217 |
DHS |
Hurricane King |
FL |
87 |
1218 |
Donic |
Waldner Senso Carbon |
|
85 |
1221 |
Stiga |
Optimum Sync |
|
|
1224 |
Butterfly |
Bazelart |
ST |
83 |
1225 |
Yinhe |
W-6 |
FL |
85 |
1225 |
Yinhe |
W-6 |
|
85 |
1225 |
Ross Leidy |
Storms of Jupiter |
ST |
85 |
1226 |
Butterfly |
Adolescen |
|
89 |
1227 |
Tibhar |
IV-L Light Contact |
|
81 |
1227 |
Nittaku |
ANV WL |
|
77 |
1230 |
Stiga |
Clipper CR |
|
|
1234 |
Yinhe |
980 |
|
|
1234 |
Yinhe |
Stock |
ST |
81 |
1234 |
Yinhe |
Stock Premium |
|
80 |
1234 |
ARTTE |
Nuvola |
ST |
85 |
1237 |
Stiga |
Offensive NCT |
|
82 |
1239 |
Butterfly |
Boll Spark |
FL |
82 |
1240 |
Butterfly |
Boll Spark |
|
82 |
1240 |
Darker |
7P-2A.DF |
ST |
82 |
1240 |
Donic |
Persson Powerallround |
|
|
1240 |
Nittaku |
Violin |
ST |
88 |
1240 |
Nittaku |
Violin |
|
88 |
1240 |
Stiga |
Tube Light |
|
90 |
1241 |
NEXY |
Amazon |
ST |
79 |
1242 |
Avalox |
Blue Thunder 555 |
|
84 |
1243 |
Avalox |
AVX Blue Thunder 550 |
|
|
1246 |
Nittaku |
Acoustic |
ST |
79 |
1246 |
OSP |
Virtuoso |
SQST |
86.1 |
1246 |
OSP |
Virtuoso |
SQST |
89.3 |
1248 |
Joola |
Carbon Schweden |
|
84 |
1250 |
Yasaka |
Extra |
|
|
1251 |
Butterfly |
Jonyer-Hinoki |
|
74 |
1260 |
Nittaku |
Latika |
ST |
84 |
1260 |
Stiga |
Hypertech 35/45 |
|
80 |
1260 |
Tibhar |
Allround Classic Junior |
|
|
1260 |
Tibhar |
Icon Sensitec |
|
83 |
1261 |
Cornilleau |
Hinotec ALL+ |
FL |
84 |
1263 |
Donic |
Waldner Offensiv 2016 Limited |
|
|
1263 |
Tibhar |
Xeon Sensitec |
|
|
1264 |
Butterfly |
Korbel OFF- Japan |
|
88 |
1265 |
Stiga |
Saive Power WRB |
|
|
1265 |
NEXY |
Lissom |
ST |
84 |
1266 |
NEXY |
Spartacus |
FL |
82 |
1269 |
Butterfly |
Schlager Precision |
|
80 |
1270 |
Nittaku |
Runlox 5 |
|
88 |
1271 |
Donic |
Waldner Dicon |
|
|
1273 |
OSP |
Virtuoso |
SQST |
89.8 |
1274 |
Stiga |
Metall Wood |
|
91 |
1275 |
NEXY |
Lissom |
FL |
87 |
1278 |
Avalox |
P500 |
|
88 |
1280 |
Nittaku |
ANV |
|
91 |
1280 |
Butterfly |
Yoshida Kaii |
|
|
1281 |
Donic |
Waldner Diablo Senso |
|
|
1282 |
Stiga |
Allround NCT |
|
82 |
1282 |
Andro |
Leader |
|
86 |
1288 |
Stiga |
Ebenholz NCT VII |
|
|
1288 |
Yinhe |
Earth-1 |
CO |
87 |
1288 |
Stiga |
Arctic Wood |
ST |
82 |
1289 |
Nittaku |
Acoustic |
ST |
85 |
1289 |
Stiga |
Offensive Wood NCT |
|
85 |
1290 |
NEXY |
Tamar VII |
ST |
|
1291 |
Nittaku |
Tenor |
FL |
91 |
1291 |
Stiga |
Ebenholz NCT V |
|
|
1291 |
Nittaku |
Latika |
ST |
80 |
1296 |
Butterfly |
Korbel OFF Magic Hand |
|
93 |
1297 |
OSP |
Virtuoso+ |
SQST |
89 |
1298 |
Yinhe |
2011 |
|
92 |
1300 |
Avalox |
P500 |
|
80 |
1303 |
Stiga |
Tube Light |
|
|
1303 |
Weltklasse |
Futec II |
|
|
1304 |
Yasaka |
Ma Lin Soft Carbon |
|
90 |
1305 |
Stiga |
Clipper |
|
|
1307 |
Butterfly |
BalsaCarbo X3 |
|
|
1309 |
Butterfly |
Schlager Precision |
|
84 |
1309 |
NEXY |
Calix |
ST |
84 |
1309 |
Yinhe |
K-3 |
FL |
86 |
1310 |
Yinhe |
K-3 |
|
86 |
1310 |
Nittaku |
Septear |
|
79 |
1311 |
Donic |
Persson Powerallround |
|
80 |
1313 |
Stiga |
Clipper Wood |
|
89 |
1313 |
Avalox |
BT 555 |
|
|
1315 |
Joola |
S. Fetzner Carbon |
|
|
1317 |
NEXY |
Calix |
ST and FL |
|
1320 |
NEXY |
Color |
FL |
89 |
1320 |
Nexy |
Color |
|
89 |
1320 |
Stiga |
Hybrid Wood |
|
85 |
1321 |
Stiga |
Hybrid Wood |
|
99 |
1322 |
Butterfly |
Defence ST |
|
|
1323 |
NEXY |
Olam |
ST |
83 |
1323 |
Nittaku |
ANV WL |
|
|
1324 |
Butterfly |
Innerforce AL |
|
91 |
1326 |
OSP |
Virtuoso |
|
88 |
1328 |
Tulpe |
702 |
|
|
1331 |
Darker |
Legato Point Carbon |
FL |
81 |
1333 |
Nittaku |
Acoustic |
ST |
85 |
1333 |
OSP |
Virtuoso |
SQST |
87.6 |
1333 |
TT-Manufaktur |
Basalt |
ST |
|
1333 |
NEXY |
Arirang |
ST |
85 |
1337 |
OSP |
Virtuoso+ |
CO |
88 |
1337 |
NEXY |
Calix |
FL |
83 |
1340 |
Butterfly |
Innerforce AL |
FL |
88.5 |
1341 |
Tulpe |
Black Power |
|
|
1343 |
Stiga |
Clipper Wood |
|
|
1344 |
TT Manufaktur |
Spinmaster Plus |
|
|
1344 |
DHS |
PF4-32 |
|
|
1345 |
Avalox |
BT 777 |
|
90 |
1348 |
NEXY |
Peterpan |
ST and FL |
|
1349 |
NEXY |
Rubicon |
ST and FL |
|
1351 |
Butterfly |
Korbel SK7 |
|
|
1355 |
NEXY |
Peterpan |
ST |
85 |
1358 |
Stiga |
Ebenholz NCT V |
|
88 |
1358 |
NEXY |
Peterpan |
ST |
85 |
1359 |
NEXY |
Peterpan |
ST |
85 |
1370 |
American Hinoki |
Ancient Kauri |
FL |
|
1374 |
Stiga |
Ebenholz V |
|
90 |
1375 |
Andro |
Super Core System off |
|
|
1381 |
Yinhe |
M-6 |
|
86 |
1390 |
NEXY |
Kanaph |
ST |
84 |
1392 |
XIOM |
Michelangelo |
|
|
1393 |
NEXY |
Chedech |
ST and FL |
|
1395 |
Stiga |
Tube Aluminium |
|
83 |
1396 |
Ross Leidy |
Rapscallion |
ST |
84 |
1398 |
Stiga |
Tube Carbo |
|
88 |
1399 |
Tibhar |
Nimbus OFF |
|
|
1400 |
Yinhe |
896 |
|
84 |
1400 |
Yinhe |
W-5 |
|
85 |
1400 |
Butterfly |
Keyshot Light |
|
82 |
1408 |
Stiga |
Tube Carbo |
|
|
1420 |
Nittaku |
Septear |
|
|
1423 |
Donic |
Persson PowerCarbon Senso |
|
90 |
1431 |
Gewo |
Power System 4.0 |
|
|
1441 |
Butterfly |
Innerforce ULC |
|
|
1442 |
Butterfly |
Timo Boll ALC |
|
|
1450 |
Butterfly |
Viscaria |
|
|
1452 |
Butterfly |
Boll Spirit |
|
87 |
1453 |
Butterfly |
Mazunov |
|
|
1455 |
Soulspin |
Koto Medium Speed |
3DST |
86 |
1455 |
Yinhe |
K-1 |
|
87 |
1455 |
Butterfly |
Boll Spirit |
|
96 |
1458 |
Butterfly |
Keyshot Light |
|
84 |
1461 |
Weltklasse |
Speedster |
|
|
1465 |
ARTTE |
Mantra |
|
|
1473 |
Butterfly |
Jun Mizutani |
|
90 |
1475 |
XIOM |
Stradivarius |
|
|
1481 |
Butterfly |
Kiso Hinoki V |
ST |
79 |
1482 |
NEXY |
Zealot |
ST |
83 |
1491 |
Nittaku |
S-5 |
ST |
|
1500 |
NEXY |
Calix II |
FL |
86 |
1505 |
Nimatsu |
Maestro ALL+ |
ST |
80 |
1517 |
Butterfly |
Kiso Hinoki V |
|
79 |
1527 |
Butterfly |
Keyshot Light |
|
85 |
1531 |
Donic |
Opticon |
|
|
1531 |
Butterfly |
Kong Linghui Spezial |
|
84 |
1538 |
Yinhe |
M-3 |
|
|
1543 |
Yinhe |
W-3 |
|
88 |
1545 |
Butterfly |
Keyshot Light |
|
83 |
1555 |
Andro |
Kinetik CF OFF- |
|
86 |
1556 |
NEXY |
Calix II |
ST and FL |
|
1556 |
Butterfly |
Michael Maze |
ST |
91 |
1566 |
Butterfly |
Michael Maze |
|
91 |
1566 |
Tibhar |
Inca |
ST |
85 |
1571 |
Donic |
Carbo System |
|
|
1574 |
Butterfly |
Timo Boll ZLC |
|
|
1576 |
Yinhe |
T-7 |
FL |
87 |
1578 |
Yinhe |
T-4 |
|
78 |
1580 |
Butterfly |
Viscaria Light |
|
|
1584 |
Yinhe |
T-7 |
|
87 |
1587 |
Butterfly |
Kiso Hinoki V |
|
83 |
1588 |
Yinhe |
T-8 |
|
|
1593 |
NEXY |
Oscar |
ST |
85 |
1601 |
Yinhe |
T-7 Light |
ST |
65 |
1604 |
NEXY |
Qabod |
ST |
88 |
1609 |
Tibhar |
Black Carbon |
|
80 |
1610 |
Yinhe |
T-2 |
|
|
1623 |
BBC |
9-10-9 |
CO |
83 |
1631 |
XIOM |
Jazz |
FL |
83 |
1635 |
Yinhe |
T-5 |
|
|
1639 |
Tibhar |
Samsonov Carbon |
|
97 |
1651 |
Nimatsu |
Maestro OFF |
FL |
80 |
1654 |
Tibhar |
Samsonov Carbon |
|
|
1657 |
Butterfly |
BalsaCarbo X5 |
|
75 |
1659 |
Butterfly |
Photino |
|
|
1661 |
Best of Five |
Carbon AR Light |
|
|
1674 |
Butterfly |
Gergely |
|
94 |
1677 |
Yinhe |
T-3 |
|
86 |
1695 |
Butterfly |
Schlager Light |
|
86 |
1700 |
Butterfly |
Primorac Carbon OFF+ |
|
|
1705 |
Butterfly |
Gergely Carbon |
|
|
1710 |
Imperial |
Balsa Carbon |
|
|
1716 |
Yinhe |
T-6 |
|
|
1777 |
TSP |
Hinoki Pure |
|
88 |
1790 |
Joola |
Rossi Force |
|
|
1794 |
Butterfly |
Schlager Carbon |
|
|
1950 |
Yinhe |
T-11 |
|
70 |
2000 |
Nittaku |
Excellent AAA |
|
|
2006 |
Yinhe |
T-1 |
|
|
2044 |
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|
Posted By: arg0
Date Posted: 07/01/2017 at 10:29am
Just wanted to cross-link this with http://mytabletennis.net/forum/forum_posts.asp?TID=79533" rel="nofollow - another thread , dealing with the same subject.
------------- Nexy Arche & Nittaku Violin LG. Join the forum_posts.asp?TID=47778" rel="nofollow - Nexy Clan ! Also member of Violin & 1-Ply clans.
|
Posted By: adyy
Date Posted: 11/22/2018 at 4:51am
I have read this thread and the http://mytabletennis.net/forum/forum_posts.asp?TID=79533" rel="nofollow - other thread and I measured a blade that I have just built. And I have some questions, if someone can help me.I have made the Spectral Analiser analyse and Audacity recording at the same time. Here is the data obtained with Vuche Spectral Analiser:
and here is what I recorded with Audacity:
So, the data obtained is close (in the 50 hz range quoted above), respectively 1442Hz@-84dB and 1489Hz@-22dB.
But why the decibel value is so different, since it is the same blade and the measurements/recording with these 2 tools what made simultaneous? The phone was placed near the blade and the "laptop" microfone was some Logitech headset microphone placed around 15 cm away from the blade.
Here is also the MP3, attached: uploads/36838/BMB_Fiber_Elastic_5.zip" rel="nofollow - uploads/36838/BMB_Fiber_Elastic_5.zip
Is it normal or I may have made some mistake? Thanks!!!
|
Posted By: zeio
Date Posted: 11/22/2018 at 5:40am
The units are different. dB ≠ dBFS(decibels relative to full scale).
https://www.audiomasterclass.com/newsletter/what-is-the-difference-between-0-db-and-0-dbfs" rel="nofollow - https://www.audiomasterclass.com/newsletter/what-is-the-difference-between-0-db-and-0-dbfs
Decibels are used to describe differences or changes in level. 0 dB means 'no change'.
Values in dBFS are used to describe signal levels in comparison with the highest level a WAV file can handle. |
------------- Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare)
+ Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃)
= 184.8g
|
Posted By: adyy
Date Posted: 11/22/2018 at 7:34am
Thanks Zeio! The Lightbulb is brighter now!And I suppose the difference between the 1442Hz (Huawei P10) and the 1489Hz (Logitech mic + laptop sound chip) is caused by the different hardware used. And it is in the 50 Hz normal "variation" range. So, no measurement mistakes.
|
Posted By: adyy
Date Posted: 11/22/2018 at 8:03am
Now there is a new question, for the more experienced than me. I just measured another 3 blades:
1) Yinhe T8s - 1593Hz @ 84db 2) Nittaku Flyatt Carbon - 1378Hz @ 76db
3) *another blade made by me - 1335Hz @ 82db
Between 1) and 2) there is a clear difference. Yinhe is faster than the Nittaku in real life too. But the 2) and 3) have the frequency in the 50hz range, so they should be very close one to the other in speed. But what might the dB difference mean? My first tought is that because they have different COR, the 3rd returns more energy, louder! But it returns the energy to the ball or it dissipates to the environment as sound energy? I would tend to think the second.
Or that db values should be totally ignored because they mean nothing?
* this is a mahogany-fiberglass-ayous-fiberglass-mahogany blade of 5.5mm tickness, 91.8 grams. * it is built for a colleague at work and was not tested yet (he is waiting for the rubbers), so I have no idea how it plays. But I estimate it to be somewhere around an ALL+ rating.
|
Posted By: simone
Date Posted: 11/30/2020 at 7:09pm
I posted something like yours, something like 3 years ago, i thought i was the first to have this idea... so similar
http://mytabletennis.net/forum/forum_posts.asp?TID=82254" rel="nofollow - tabletennis blade stiffness measurement
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Posted By: simone
Date Posted: 03/03/2021 at 6:05pm
for some reason the link to the manuscript I wrote seems not to work. however ... for those who are interested in here are two videos I have uploaded on youtube three years ago
https://youtu.be/QKwVp_jCqa8" rel="nofollow - https://youtu.be/QKwVp_jCqa8
in this second one the test is not affected by the kind of playing ball used
https://youtu.be/I-5znpJCfT0" rel="nofollow - https://youtu.be/I-5znpJCfT0
if someone is interested in I can upload the manuscript again
With a smartphone it is easier....
|
Posted By: simone
Date Posted: 03/20/2021 at 10:15am
for those who are interested in comparing the manuscript I wrote to the topic in this post you can copy the following URL in the address bar... so similar
http://mytabletennis.net/forum/uploads/36100/table_tennis_blade_stiffness_measurement.pdf" rel="nofollow - http://mytabletennis.net/forum/uploads/36100/table_tennis_blade_stiffness_measurement.pdf
|
Posted By: stiltt
Date Posted: 03/20/2021 at 12:28pm
Hi Simone I took the freedom to edit your links here and in your original post in 2018. They work now. I am not sure what happened.
------------- /forum/topic91512_page1.html#1124698" rel="nofollow - sales - forum_posts.asp?TID=19315" rel="nofollow - feedback
|
Posted By: stiltt
Date Posted: 03/20/2021 at 12:30pm
There is that thread that h0n1g started after being inspired by slevin's thread who got himself inspired by I do not know who
http://mytabletennis.net/forum/blade-speed-comparison-sheet_topic79593_page1.html" rel="nofollow - http://mytabletennis.net/forum/blade-speed-comparison-sheet_topic79593_page1.html
------------- /forum/topic91512_page1.html#1124698" rel="nofollow - sales - forum_posts.asp?TID=19315" rel="nofollow - feedback
|
Posted By: stiltt
Date Posted: 03/20/2021 at 12:33pm
here's slevin's thread
http://mytabletennis.net/forum/expressing-relative-blade-speed_topic79533_post986262.html" rel="nofollow - http://mytabletennis.net/forum/expressing-relative-blade-speed_topic79533_post986262.html
we know who started it all here tho, arg0!!!
------------- /forum/topic91512_page1.html#1124698" rel="nofollow - sales - forum_posts.asp?TID=19315" rel="nofollow - feedback
|
Posted By: stiltt
Date Posted: 03/20/2021 at 12:44pm
There is that study linked in many places: http://www.researchgate.net/publication/271637905_Vibro-acoustic_of_table_tennis_rackets_at_ball_impact_Influence_of_the_blade_plywood_composition#pf4" rel="nofollow - https://www.researchgate.net/publication/271637905_Vibro-acoustic_of_table_tennis_rackets_at_ball_impact_Influence_of_the_blade_plywood_composition#pf4
http://www.sciencedirect.com/science/article/pii/S187770581201716X" rel="nofollow - https://www.sciencedirect.com/science/article/pii/S187770581201716X
http://www.sciencedirect.com/science/article/pii/S1877705814005840" rel="nofollow - https://www.sciencedirect.com/science/article/pii/S1877705814005840
http://pubmed.ncbi.nlm.nih.gov/29638189/" rel="nofollow - https://pubmed.ncbi.nlm.nih.gov/29638189/
http://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1462578?journalCode=rjsp20" rel="nofollow - https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1462578?journalCode=rjsp20
http://reader.elsevier.com/reader/sd/pii/S1877705814005840?token=9C9FB522D112115F2C8D28DD429B26EBE3AA7B02C50D5DDD32B3915D922FEFCC6AD17EBCA5097CAC39D6918B803CDD3A" rel="nofollow - https://reader.elsevier.com/reader/sd/pii/S1877705814005840?token=9C9FB522D112115F2C8D28DD429B26EBE3AA7B02C50D5DDD32B3915D922FEFCC6AD17EBCA5097CAC39D6918B803CDD3A
------------- /forum/topic91512_page1.html#1124698" rel="nofollow - sales - forum_posts.asp?TID=19315" rel="nofollow - feedback
|
Posted By: simone
Date Posted: 03/20/2021 at 12:58pm
stiltt wrote:
There is that study linked in many places: https://www.researchgate.net/publication/271637905_Vibro-acoustic_of_table_tennis_rackets_at_ball_impact_Influence_of_the_blade_plywood_composition#pf4" rel="nofollow - https://www.researchgate.net/publication/271637905_Vibro-acoustic_of_table_tennis_rackets_at_ball_impact_Influence_of_the_blade_plywood_composition#pf4
https://www.sciencedirect.com/science/article/pii/S187770581201716X" rel="nofollow - https://www.sciencedirect.com/science/article/pii/S187770581201716X
https://www.sciencedirect.com/science/article/pii/S1877705814005840" rel="nofollow - https://www.sciencedirect.com/science/article/pii/S1877705814005840
http://pubmed.ncbi.nlm.nih.gov/29638189/" rel="nofollow - https://pubmed.ncbi.nlm.nih.gov/29638189/
http://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1462578?journalCode=rjsp20" rel="nofollow - https://www.tandfonline.com/doi/abs/10.1080/02640414.2018.1462578?journalCode=rjsp20
http://reader.elsevier.com/reader/sd/pii/S1877705814005840?token=9C9FB522D112115F2C8D28DD429B26EBE3AA7B02C50D5DDD32B3915D922FEFCC6AD17EBCA5097CAC39D6918B803CDD3A" rel="nofollow - https://reader.elsevier.com/reader/sd/pii/S1877705814005840?token=9C9FB522D112115F2C8D28DD429B26EBE3AA7B02C50D5DDD32B3915D922FEFCC6AD17EBCA5097CAC39D6918B803CDD3A
|
These works do not threat the subject in the sameway, most of them have a different approach
|
Posted By: simone
Date Posted: 03/20/2021 at 1:03pm
stiltt wrote:
here's slevin's thread
http://mytabletennis.net/forum/expressing-relative-blade-speed_topic79533_post986262.html" rel="nofollow - http://mytabletennis.net/forum/expressing-relative-blade-speed_topic79533_post986262.html
we know who started it all here tho, arg0!!! | some doubt on the date... however I talk about the explanations of the prcedure in this topic, exactly the same I used in the manuscript. this can't be a coincidence,
|
Posted By: stiltt
Date Posted: 03/20/2021 at 1:14pm
Maybe it's an instance of convergence thinking?
or http://www.livescience.com/convergent-evolution.html" rel="nofollow - convergent evolution : if you give them enough time, table tennis players will knock their bare blade's handle on their skull holding the blade's head on the opposite edges with the thumb and middle finger.
------------- /forum/topic91512_page1.html#1124698" rel="nofollow - sales - forum_posts.asp?TID=19315" rel="nofollow - feedback
|
Posted By: simone
Date Posted: 03/20/2021 at 1:15pm
I am talking about this topic, in the explanation of the procedure i read the same words I wrote in the manuscript
|
Posted By: stiltt
Date Posted: 03/20/2021 at 2:01pm
Too bad wayback saved the thread only once between 2010 and 2017.
https://web.archive.org/web/2017*/mytabletennis.net/forum/forum_posts.asp?TID=38419" rel="nofollow - https://web.archive.org/web/2017*/http://mytabletennis.net/forum/forum_posts.asp?TID=38419 http://web.archive.org/web/20170921135728/mytabletennis.net/forum/forum_posts.asp?TID=38419" rel="nofollow - https://web.archive.org/web/20170921135728/mytabletennis.net/forum/forum_posts.asp?TID=38419 What are the words you are referring to?
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Posted By: simone
Date Posted: 03/21/2021 at 10:17am
I opened a thread with the same subject in an italian forum years ago
https://tennis-tavolo.com/threads/misura-rigidita-di-un-telaio-con-unapp-per-smartphone.47542/" rel="nofollow - https://tennis-tavolo.com/threads/misura-rigidita-di-un-telaio-con-unapp-per-smartphone.47542/
ok is in italian, but... same questions, same answers... same numbers.... what a coincidence..
|
Posted By: thejnal
Date Posted: 06/14/2021 at 5:08am
Im am physics teacher. The measuring makes no sence. The frequency depends eg on where you hold the bat or where you hit it. The stiffness has nothing to do with frequency. Sorry.
|
Posted By: arg0
Date Posted: 06/14/2021 at 5:23am
Have you actually tried? You would be surprised: the dependency you talk about is minimal for the main frequency. Just keep your grip loose.
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Posted By: Hipnotic
Date Posted: 06/14/2021 at 6:22am
thejnal wrote:
Im am physics teacher. The measuring makes no sence. The frequency depends eg on where you hold the bat or where you hit it. The stiffness has nothing to do with frequency. Sorry.
|
I'm no teacher, but one thing I know is that when we are conducting an experiment, a set of ground rules must be established, in order to control the variables and produce results that can be comparable with each other. There were so many arguments you could've made, but managing where and how you hit the blade are the easiest ones to control, so they aren't gonna be the reason to invalidate this test.
By the way, have you tried to measure this variation yourself? Because I can tell you it won't be much.
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Posted By: Zwill
Date Posted: 06/14/2021 at 6:54am
It's quite scary how similar blades measure almost identical. I have a TBS black tag, Yinhe V14pro and a Yinhe D715 which is all very similar blade and they all measure around 1425-1450hz, their manufacturing year, weight handle are different but they measure the same.
But I wouldn't give too much thought to the test either, it's good for a general idea I think. Like above mentioned blades measure 1425hz+, but my Joola Trinity only measures "only" 1400hz. However the Trinity is significantly stiffer and faster in actual play. An 1300hz Fang Bo carbon doesn't feel only 7-8% slower, it's much much slower and flexier.
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Posted By: arg0
Date Posted: 06/14/2021 at 7:22am
thejnal wrote:
Im am physics teacher. The measuring makes no sence. The frequency depends eg on where you hold the bat or where you hit it. The stiffness has nothing to do with frequency. Sorry. |
Besides, I had given for granted that you were questioning the blade being hold by hand and the variable contact point. As to the overall approach, there are several scientific publications on the subject, where the blade is clamped. The latest I am aware of are by Manin et al in Proc. Conf. International Sports Engineering Association (ISEA), but I have not kept up to date.
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Posted By: cole_ely
Date Posted: 06/15/2021 at 9:19pm
from a statistical standpoint, I would think you might want to get a good number of bounces recorded for analysis. A good algorithm would have you it remove your hand and re grab the blade, then bounce it a few times and repeat the process; then take averages or whatever. Seems like it would be more realistic than trying to find a standard clamp. You will be holding the blade in your hand with a lot of variation as you play
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Posted By: simone
Date Posted: 09/18/2021 at 4:50am
thejnal wrote:
Im am physics teacher. The measuring makes no sence. The frequency depends eg on where you hold the bat or where you hit it. The stiffness has nothing to do with frequency. Sorry.
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I am an egineer
trust me ... try it, try to repeat the test few times and compare the outcome (should be about the same), and with the feeling when using that blade. should not hit the ball on the edge of the blade, (as when when you play).
Obviously it is not a laboratory test, but reliable for the purpose.
just for curiosity, give a look at the video
https://youtu.be/QKwVp_jCqa8" rel="nofollow - https://youtu.be/QKwVp_jCqa8
and
https://youtu.be/I-5znpJCfT0" rel="nofollow - https://youtu.be/I-5znpJCfT0
I found the test easy to make and useful
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