Bouncing a ball on a blade

[Xanderngzien]

Can someone please tell me how to understand the characterisitcs of a blade through the sound of bouncing a ball on it. I only have some knowledge about it so can someone please explain it to me

If i feel vibration what does it mean? Also i have a allwood blade but the sound is quite high pitch? Does high pitch mean it has good dwell time etc

 

[UpSideDownCarl]

I personally have never tried or worried about what a blade sounds or feels like when the rubbers are not on. Once the rubbers are on and you hit with a setup, you can tell how it plays.


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[shinshiro]

I think a better way to test a bare blade may be the "knock on head" test. To do this you have to hold the side of blade face with your tumb and middle finger, than you knock the handle on your head and pay atention on the sound it makes.

From what I've read, that way you can hear the pitch and sound lenght. The pitch is suposed to indicate speed and hardness (higher = faster/harder), while sound duration indicates the amount of vibration and flex (longer sound = more vibration/flex).

I don't know how precise is this method but from the little I tested it kinda worked, I think... I tested Virtuoso Off-, Virtuoso+, Ovtcharov True Carbon and Nittaku Miyabi. The result was as follow if I remember correctly:

Pitch (higher to low, or faster/harder to slower/softer): NM > OTC > V+ > V-
Sound duration (higher to low, or flexier/more vibration to stiff/less vibration): V- > V+ > OTC > NM

The only strange thing is that NM is rated faster than OTC according to this test. I haven't played with NM so I can't confirm, but I suspect it is wrong. Maybe one ply hinoki blades work different, it seems to be a kind of unique type of wood. The other results sounds right (though I haven't played with V+ either, it is a well known fact that V+ is faster and harder than V-).

This test probably works better when comparing blades of same type (allwood vs allwood, composite vs composite, alc vs alc, etc). Has anyone compared more blades with this kind of test? It would be very interesting to know how reliable is this, it is not always that you have a chance to do a proper test with blade + rubbers you know + ball you know when you go to buy a new blade, and this is an easy method to compare with your current blade.

Edit: just to add some info, it is easier to notice difference in sound by this method then bouncing the ball on blade. I couldn't differenciate the sound of V- and V+ on ball bouncing test, but knocking then on the head produces a different sound: the sounds are similar, but there is clearly some difference!

 

[langel]

I think such tests are more theoretical than applicabale in practice. Sound will depend a lot on the specific structure, but won't be a reliable indicator, especially for composite blades. I have a 7wood+4carbon blade which with this test produces lowest pitch like it's hollow, but it's neither soft nor the most flexy. Besides that regarding flexibility most of the modern composite blades have non-linear dymanically changing flex depending on the impact strength and direction, so such tests most probably won't tell you much and in some cases will even give wrong information.

 

[pgpg]

I think in some places (Russia, for instance) it became part of TT lore - you *must* do this before you buy the blade, at least judging by the forums I read there. In US, not so much, perhaps because opportunities to do this are pretty much nonexistent, with most of blades being purchased online.

I fully admit I have no idea what to do with this bounce test, perhaps someone who does it regularly could chime in on what they are looking for with it.

 

[Kristoffer]

Since I am new to this site I'might not allowed to post links to other sites

 

[Kristoffer]

Since I am new to this site I'might not allowed to post links to other sites, but the thoughtsontabletennis blog has an article on blade design, that answers the question.

 

[bobpuls]

There are guys which are measuring frequency off blades after ball hits it to get the speed info from the peak frequency
Here you can find a link for ind and software for measurement ...
https://docs.google.com/spreadsheets/d/1tnzuhP98Iwl3_ZYIKs770Z4GeEXB1cPaF6xXC3IMLfg/edit#gid=0

 

[langel]

Just a very subtle remark - in the measurement data table Xiom Vega Tour is stated as 82 gr. It's standart weight is 85 gr. but most vendors have in stock only heavyer pieces. I turned the world to find 3 blades of 85 gr. So 82 gr. Vega Tour is possible, but not disscussible as an etalon for measurement at all. The same is with Vega Pro and Vega Euro - both have standart weight of 82 gr., but the measured Pro is 87 and the Euro - 79.

Just have measuered my new unused Xiom Vega Tour 85 gr. - between 1670 and 1900 with different balls, lowest with DHS 40 3*, highest with Xushaofa 3*. So is it supposed to be the fastest blade? I wonder what would be the result with the most terrible sounding new German Butterfly balls?

When I change the rubbers of my fastest blades I will measure them too, but as I've alredy mentioned, one of them is sounding as low as a hollow.

So I absolutely don't trust such measurements.

 

[UpSideDownCarl]

Since I am new to this site I'might not allowed to post links to other sites, but the thoughtsontabletennis blog has an article on blade design, that answers the question.

When you have 5 or more posts, then you can post links.

Welcome to the forum.


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[langel]

USD, I think that your personal point of view would be very well apreciated on this thread. It's absolutely yours teritory.
Please don't mind the goons and answer the matterial problem

 

[UpSideDownCarl]

USD, I think that your personal point of view would be very well apreciated on this thread. It's absolutely yours teritory.
Please don't mind the goons and answer the matterial problem

I think you are referring to me and not the US Currency.

I already answered. I personally think that what you feel when the blade is in your hand with rubbers on and you get to put the setup through its paces is much more valuable. The big crunch of an OSP Virtuoso+ compared to the crisp snap of a Stiga Clipper Classic, compared to the deep thud/poc of a Butterfly Primorac Off-, compared to the clean, crisp pop of a Butterfly Viscaria is not really something you are going to appreciate and understand from bouncing a ball on a naked blade.

At least, that is my opinion on the subject.

I can play with any of the blades I mentioned. They will all work for me. But I will prefer the deeper, darker crunch tones of the slower Limba-Limba-Ayous blades I mentioned (V+ & Primorac). Something about the deeper tones makes me happy. And you won't feel that without full impact and seeing how the setup responds when you do touch shots and power shots.

 

[BeGo]

Can someone please tell me how to understand the characterisitcs of a blade through the sound of bouncing a ball on it. I only have some knowledge about it so can someone please explain it to me

If i feel vibration what does it mean? Also i have a allwood blade but the sound is quite high pitch? Does high pitch mean it has good dwell time etc

I did it regularly, to check several think

Hardness, harder blade give higher freqs / note

Where the COG by balancing on ball

Is the bounce equal for whole blade face, by, err, bouncing the ball on whole blade face [emoji23] . Also catch the sweet spot

How "communicative" the blade is. What we feel in hand is not the freqs, but the amplitude. [emoji6]






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[langel]

But I will prefer the deeper, darker crunch tones of the slower Limba-Limba-Ayous blades I mentioned (V+ & Primorac). Something about the deeper tones makes me happy. And you won't feel that without full impact and seeing how the setup responds when you do touch shots and power shots.

Yes, that it is!
Rich and fine music with well defined pleasant reverberations!
Harmony is everything!
In TT harmony is well explained with synergy.
Synergybeween blade and rubbers, and synergy between the blade-rubbers system and the player himself.
After that comes all other.
Measuring just one characteristic with non-calibrated equipment, with methods for a single material, but not for a complex system of differnet materials, in an uncontrolled envirenment, measured with uncalibrated instruments and the most importent:
- don't having in mind the hundreds of other dependences,

will give you nothing.

Critical reading, Critical thinking, combining producers info, forum's info and most of all - personal experiance === there is the answer.

 

[UpSideDownCarl]

Yes, that it is!
Rich and fine music with well defined pleasant reverberations!
Harmony is everything!
In TT harmony is well explained with synergy.
Synergybeween blade and rubbers, and synergy between the blade-rubbers system and the player himself.
After that comes all other.
Measuring just one characteristic with non-calibrated equipment, with methods for a single material, but not for a complex system of differnet materials, in an uncontrolled envirenment, measured with uncalibrated instruments and the most importent:
- don't having in mind the hundreds of other dependences,

will give you nothing.

Critical reading, Critical thinking, combining producers info, forum's info and most of all - personal experiance === there is the answer.

Now I think you have convinced me of the benefits of bouncing a ball on a naked blade by overstating the downsides and adding some stuff that is a bit over the top like the tools for measuring the sound and the uncontrolled environment.

They do have an app that will tell you the pitch and decibel level. And you can make the bounce test fairly controlled in spite of there being many variables.


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[UpSideDownCarl]

A detail. I don't really read pulses. But I will "read" people's pulses in the work I do and get a sense of what is going on for them.

It is totally not scientific. There is nothing I can say that would support my intuitions when I feel someone's pulse.

Two weeks ago I was with a friend who was not feeling well. I felt her pulse and said, "your heart rate is slow but the intensity is strong."

Later that day she was taken to the hospital and her blood pressure was high and her heart rate was slow.

In my work, I am often feeling people's pulses when they seem more stressed than normal from a series of exercises. So I have a sense of what I am feeling. And maybe the people who do the bounce test on the blades when they are naked can tell more than I thought.

I will continue to like my method of putting a racket through its paces. But, maybe people can tell more than I was considering.


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[langel]

Ok, Carl, what I meant was that 'even if we agree with the sense of the test we could not perform it in a trusted way".
We don't have a calibrated ball we could use for the test allover the world. Even balls from one pack may give different results.
We don't measure humidity and I.m sure that even 20% deviation of humidity will give different results.

But, after all, I would agree tha this test may be usable to compare several pieces of one and the same model in one place with one ball.

 

[UpSideDownCarl]

Hopefully you know I was playing around.

But I am not going to try and derail other people's rituals too badly.

When I was a professional inline skater, I would always put on my left skate first before skating a ramp. If I ever started to put the right skate on first, I would take it off, get off the ramp, and then go back up to put the skates on left foot first.


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[langel]

Yes, Rafael Nadal is symbolic in that.