Numerical Analysis of table tennis blades

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Ok, I don't want to argue and I'm not doing it at all.
Just want to clarify some points - I'm very familiar with these tables and we have discussed the pitch tests many times in this forum. All these tests are held by many people from all over the world. But they all are executed by simple drop of the ball. And yes, there is a corelation, though some results vary a lot. As these tests are executed with a very low ball speed, they would be more precise with slower blades, blades with simpler composition and blades with tighter range - no matter def, all or off but tighter in performance. The more complicated the structure of the blade is and/or the more wide is its speed range, the more unaccurate or even false such a test may be. An example - the 11 ply Palio v1 /7 wood, 4 carbon/ has a low-speed ball pitch like a slower 5 ply DEF wood, but in fact is OFF, even OFF+. Palio TNT-1, 7+2, is mine stiffest and hardest OFF+, even OFF++, but because is massive and thick its pitch is like a OFF-. Rosi Emotion sounds like OFF, but is All+, OFF- max. All mine Xiom Vega Tour blades have higher pitch than those in the tables, but still I can't say are they faster - it may be just because they are of lower weight. Besides that some blades are more sensitive to the balls and with different balls they sound different - it may be because of the outer ply, overall composition and structure, etc.
So I don't say that there is no corelation at all, a pitch test may be somewhat indicative, but has to be trusted with care. For me it would be useble if you compare to chose a blade between several pieces of same model.

You have to the table i have posted. For example, a blade with e=5.2mm, 60g and F=1300Hz would be off+. A blade with e=6.2mm, 60g and F=1300Hz would be All.

Blade 1 would be very difficult to manufacture. It has a density of 0,5 g/cm3 and a stiffness of 7000 MPa, there's no way that could be done without employing composite materials, and the ratio would be most likely illegal. Blade 2 is easily doable with normal woods.
 
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Now in a more user friendly version. This is an example for a 5.6 mm blade. You input the weight without handles (about 20g), the frequency and see where it falls on the chart.

5.6.jpg
 

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Can you upload the datasheet? Did you make it excel or something like that?
Now in a more user friendly version. This is an example for a 5.6 mm blade. You input the weight without handles (about 20g), the frequency and see where it falls on the chart.

View attachment 17430

Enviado desde mi Moto G (4) mediante Tapatalk
 
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That was made in excel but i'm using google sheets. Right now it's not ready to share but when it's completed i will share a link to google sheets with all the data. I will upload the image again with a larger font. Here's the table if you want to plot your own chart

5.6
5055606570
All111410621017977942
All +12861226117411281087
Off -14381371131212611216
Off15751502143813811332
Off +17021622155314921438
 
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Ok, I don't want to argue and I'm not doing it at all.
Just want to clarify some points - I'm very familiar with these tables and we have discussed the pitch tests many times in this forum. All these tests are held by many people from all over the world. But they all are executed by simple drop of the ball. And yes, there is a corelation, though some results vary a lot. As these tests are executed with a very low ball speed, they would be more precise with slower blades, blades with simpler composition and blades with tighter range - no matter def, all or off but tighter in performance. The more complicated the structure of the blade is and/or the more wide is its speed range, the more unaccurate or even false such a test may be. An example - the 11 ply Palio v1 /7 wood, 4 carbon/ has a low-speed ball pitch like a slower 5 ply DEF wood, but in fact is OFF, even OFF+. Palio TNT-1, 7+2, is mine stiffest and hardest OFF+, even OFF++, but because is massive and thick its pitch is like a OFF-. Rosi Emotion sounds like OFF, but is All+, OFF- max. All mine Xiom Vega Tour blades have higher pitch than those in the tables, but still I can't say are they faster - it may be just because they are of lower weight. Besides that some blades are more sensitive to the balls and with different balls they sound different - it may be because of the outer ply, overall composition and structure, etc.
So I don't say that there is no corelation at all, a pitch test may be somewhat indicative, but has to be trusted with care. For me it would be useble if you compare to chose a blade between several pieces of same model.

It is true that the table is more useful to compare blades of same series or similar construction. But it is also valuable for everyone to compare different models as well! To be honest I do not see there is anything wrong with the methodology as it is simply a test using a simple drop test on a blade, a microphone embedded inside a smart phone with a free app. The purpose is that everyone can do it thus help create a table which can be useful if one knows how to interpret the data smartly enough.
What troubles me is that you state many things about your experience with different blades and claim they sound different than what reported in the table. Hearing is very subjective thus can't be used as argument. If you understand acoustics you must know that different individual has different sense of hearing. Loudness is very subjective. 2 different persons will perceive a different loudness of 2 different tones at same sound power measured by a microphone. A sick day will make one hear different, too. And a fact that very few people know is that a loudness table created by European or American folks is different than one made by Asian! Such examples is to show why you can't use your hearing to judge blades, unless you tested hundred of them and drew correct correlation consistently. If you can share some numbers based on the test methodology then it is more useful and we can treat the table more objectively.

Such simple methodology of course is not enough. But it is very good estimation and I admire who ever came up with it. Blade manufacturers have different standard of testing and come up with their own ranking of blades. They probably should use this methodology thus allow users/players to quickly estimate (emphasized estimate here) different blades.
 
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tropical, I think you missunderstood a lot of what I say and you describe things that have nothing to do with what I say.
To clarify - what I've described above is a result of using the same method as the one used by many people in the tables, its not a matter of ears and personal feeling. Its not the first time I comment exactly the same. About the different results - in these tables there are much greater differences in the measured pitch of same blades. But my point is not focussed on exactly these differences - my point is that for some structures this method will give wrong conclusions. Thats all.
 
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langel .. let me ask you where in the table data seem to be contradicting as I look at similar blades and they are all within acceptable range/tolerance.

What might cause the contradiction (if any) is: different boundary conditions (the way people hold the paddle: firm, loose, with finger on blade surface, etc.); fake blades (?), manufacturer tolerances, smart phone's microphone tolerances between brands and among brand, ...

BTW, I do not believe different types of ball or height of drop will change fundamental freq's of the blade (just pure physics).
 
langel .. let me ask you where in the table data seem to be contradicting as I look at similar blades and they are all within acceptable range/tolerance.

What might cause the contradiction (if any) is: different boundary conditions (the way people hold the paddle: firm, loose, with finger on blade surface, etc.); fake blades (?), manufacturer tolerances, smart phone's microphone tolerances between brands and among brand, ...

BTW, I do not believe different types of ball or height of drop will change fundamental freq's of the blade (just pure physics).

Differences in the table - Vega Tour - 1291 and 1421. My Tours pitch with above 1600, can't remember exactly, but I think its stated in a similar thread a year ago. About the ball - once I get to change rubbers I'll make the test right for you. I have made it and the difference is about 100 Hz.


Edit: Something else - in the tables Rosi Emotion is measured 1271 Hz. Ok, if you have had a look only on the 1291 Hz measurement of Vega Tour, you would say "yeah, they have equal speed, but Rosi is more than twice cheeper and has a hinoki outer too". Yes? But in fact Tour is much faster. Don't take it wrong as something against Rosi Emotion, its a nice blade, I have it and I like it, and I'm happy I can use it friendly when I play with beginers and weaker players, the Tour pushes me in humiliation mode, which is not good for friendly play.
 
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langel,

But did you question the authenticity of the 1421 Vega Tour? Assuming the methodology wrong because of 1 data point seems strange to me.

BTW, I've never done such test myself. I basically just look into the physics and think it makes sense from many areas. This method is just a crude and simple modal analysis. In modal analysis (a methodology to find natural freq of an object by hitting it with a hammer or shaker) people use difference hammer tips to figure out the low, med, high mode shapes (different fundamental natural frequencies of the object) manually. Regardless of how hard (relatively as different people hit the object at different force, direction,..) they hit, the mode shape will always the same, in another word the natural freq in the range (low range for example) will be the same. It means unless you change the hammer tip significantly like steel instead of rubber (bring the object fundamental freq to a different range, med as an example) where damping contributes a lot to prevent the object to be exited in the high range, the nat freq should also be the same! So I find it is hard to believe a different ball can move the nat freq of the blade. It just doesn't make any sense. If you can find differences I'd try to buy the app and do some experiments myself to figure out why.

A while back I remember I made suggestions to minimize variables to the testing. Because boundary conditions can change nat freq a lot (think about a guitar spring at different frets) anyone who want to do the test should try to do it the same way; clamping the handle with a vice at a fixed pressure (say 10 lbs on a 10cm length measured from bottom of the blade). This may not be suitable to PH as its handle is much shorter...
 
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