Dwell time

[NextLevel]

I don't want to argue about it because I fundamentally agree that sound affects the way we play, but the fact is that I am using the most precise possible language to describe this, and if you decide you don't want to understand...????? Well Ok. But that is pretty much exactly what I said.

To reiterate: Sound is vibrations carried as pressure waves through the air. It is detected by our auditory system normally, except if it is really loud and low enough frequency you can feel it in other parts of your body. The question is whether the normal sense of hearing is actually the thing that makes us say, for example, that one setup is different from another has been raised. I personally don't think it is a major contributor, but I have not done the thing experiment that would determine for sure. We all know that it sounds different when you drive the ball with an open racket angle as opposed to brushing it. Sound narrowly defined may tell us more than we think about what just happened on a shot and determine how we play.

Still, it is obvious that other organ systems in our body can detect when we hit the ball (and also how we know what racket angle we used and even how hard we hit). I personally think the MULTIPLE sensory systems that allow us do to this are a lot more important to our "feel" than sound. And they are not vibrations that are carried as waves through the atmosphere (which is why sound does not exist in space and is different underwater). Those vibrations are instead carried through the medium of the rubber/blade/handle and from there to your hands and from there to your wrist, arm, etc. (and also to the atmosphere). Those vibrations within the handle are by definition NOT SOUND. And those vibrations are detected by a set of completely different organs not found in your ears and which deaf people certainly have. Deaf people would not need functional auditory system to know when they hit the ball.

No wonder you felt that iacas was being extreme. This is clearly not what he meant and not what I mean. In Physics, which is about as precise as anything, sound waves are simply created by vibrations. Language is generally imprecise so it's more important to understand what someone is saying that to force a precision onto something that requires its fluidity to grow - make it only as precise as absolutely necessary. Of course, someone would define "sound" as being "vibrations that you can hear" then when asked why "ultrasound" is a kind of sound, will start to look like an idiot unless he is is trying to understand what other people are saying and not trying to win arguments purely on definitions.

Sound does not exist underwater or people can't hear certain sounds underwater? In any case, we now can see the source of the flame war. IT's clear that everyone understands. But in this case, you are using language to accuse people of not understanding.

 

[Der_Echte]

There was a J Pen player in Korea easily 2000 who was deaf and got by with sight.

Sent from my SM-T350 using Tapatalk

 

[NextLevel]

Okay, feeling is ACOUSTIC in nature. Does that solve the problem?

 

[UpSideDownCarl]

There was a J Pen player in Korea easily 2000 who was deaf and got by with sight.

This idea of the connection of sound and feeling is kind of cool. Now I have another story. Hahahahaha.

At Spin where I used to play a lot and now play occasionally, they always have music playing at varying volumes. During the day it is usually not that loud. Sometimes at night it is so loud you can't hear yourself shout and you can feel the sound vibrate through your body and feel it shake the roots of your hair. [emoji2]

One comical Sunday evening Der_Echte, PPHolic and I were unfortunate enough to be playing on a night where they had what they were calling "Showtune Sunday"!!!!

Thankfully this disaster of an idea only lasted for 4 weeks at which point the guy who was DJing Showtune Sunday had an argument with my favorite Spin owner and was abruptly fired.

The gist of the argument was basically summed up like this:

DJ: "How dare you try to watch the US Open tennis final while I am playing songs with Liza Minnelli talk-yelling out of tune!!!!"

Spin Owner: "Are you crazy? Or just an idiot!"

The good news is that one week after Der_Echte's ears were assaulted by some of the worst sounds the universe has ever been exposed to, the threat to our collective auditory system came to an abrupt end.

The only thing that Showtune Sunday accomplished aside from permanent ear damage for Der, PPH and OCDCarl was to bring a fairly large crowd of balding men with handlebar mustachios hoping to get their chance to be Liza Minnelli or to play her at a low budget Off Broadway theatre.

Anyway, what do Liza Minnelli and the happy men who want to be her, talk-yelling horrible songs have to do with this conversation???

Well, I must have got carried away, lost my chain of thought. I can't remember. So I guess I will change the subject and pretend it didn't happen.

At SPiN, I have played many times where you absolutely cannot hear if someone dropped an anvil next to you. And I can tell you from experience that you can still feel the ball. It's not ear plugs but I think it may block more sound than ear plugs.

By the way, here is a side story: I'll try to be short. Hehe.

When Spin had the real version of what they call "The Dirty Dozen" and winning the tournament meant you won $500.00, many people wondered why Ernesto Eubuen did so well and beat so many people who were much higher rated than he was. The thing that was unfair in the match was, he was often playing guys who were 2700+ who had never played with the light that messed up and the music that loud. Sort of like a double whammy. Whereas, at the time, Ernesto was playing in that environment on a daily basis. Did it make him play better in that environment? NO. He still played much better in a standard tournament setting than he did at the Dirty Dozen. Did playing with that kind of sensory deprivation help him play better in a regular environment. No. it didn't. His level was unchanged.

But he played less worse (I love my grammar) than the 2700+ guys he beat because he was more used to playing with SPiN's specific recipe of sensory deprivation.

What a wacky scenario!

If you don't understand what I've just said, I just want you to understand that these are the delusional rantings of some lunatic, and I have no idea who he is. [emoji2]


Sent from the Subterranean Workshop by Telepathy

 

[Der_Echte]

That Sunday really sucked to play, the weird dudes howling at the moon really did it in. Before then we were putting on a show just with or training shot sequences.

Sent from my SM-SecretSub using WhaddaYaSaytalk

 

[NextLevel]

This idea of the connection of sound and feeling is kind of cool. Now I have another story. Hahahahaha.

At Spin where I used to play a lot and now play occasionally, they always have music playing at varying volumes. During the day it is usually not that loud. Sometimes at night it is so loud you can't hear yourself shout and you can feel the sound vibrate through your body and feel it shake the roots of your hair. [emoji2]

One comical Sunday evening Der_Echte, PPHolic and I were unfortunate enough to be playing on a night where they had what they were calling "Showtune Sunday"!!!!

Thankfully this disaster of an idea only lasted for 4 weeks at which point the guy who was DJing Showtune Sunday had an argument with my favorite Spin owner and was abruptly fired.

The gist of the argument was basically summed up like this:

DJ: "How dare you try to watch the US Open tennis final while I am playing songs with Liza Minnelli talk-yelling out of tune!!!!"

Spin Owner: "Are you crazy? Or just an idiot!"

The good news is that one week after Der_Echte's ears were assaulted by some of the worst sounds the universe has ever been exposed to, the threat to our collective auditory system came to an abrupt end.

The only thing that Showtune Sunday accomplished aside from permanent ear damage for Der, PPH and OCDCarl was to bring a fairly large crowd of balding men with handlebar mustachios hoping to get their chance to be Liza Minnelli or to play her at a low budget Off Broadway theatre.

Anyway, what do Liza Minnelli and the happy men who want to be her, talk-yelling horrible songs have to do with this conversation???

Well, I must have got carried away, lost my chain of thought. I can't remember. So I guess I will change the subject and pretend it didn't happen.

At SPiN, I have played many times where you absolutely cannot hear if someone dropped an anvil next to you. And I can tell you from experience that you can still feel the ball. It's not ear plugs but I think it may block more sound than ear plugs.

By the way, here is a side story: I'll try to be short. Hehe.

When Spin had the real version of what they call "The Dirty Dozen" and winning the tournament meant you won $500.00, many people wondered why Ernesto Eubuen did so well and beat so many people who were much higher rated than he was. The thing that was unfair in the match was, he was often playing guys who were 2700+ who had never played with the light that messed up and the music that loud. Sort of like a double whammy. Whereas, at the time, Ernesto was playing in that environment on a daily basis. Did it make him play better in that environment? NO. He still played much better in a standard tournament setting than he did at the Dirty Dozen. Did playing with that kind of sensory deprivation help him play better in a regular environment. No. it didn't. His level was unchanged.

But he played less worse (I love my grammar) than the 2700+ guys he beat because he was more used to playing with SPiN's specific recipe of sensory deprivation.

What a wacky scenario!

If you don't understand what I've just said, I just want you to understand that these are the delusional rantings of some lunatic, and I have no idea who he is. [emoji2]


Sent from the Subterranean Workshop by Telepathy

You don't know what you really SOUND like... and since you aren't speaking, I must be an idiot to write that, right?

 

[Baal]

The very first post on this thread closed with this: "What is the actual cause for the sensation of more dwell?"

One of the first questions therefore entails sensory physiology. Since actual dwell times vary over some range around 1 millisecond or less, we know immediately that the receptors in our hands won't detect THAT. Clearly the vibrations in the blade set up by ball impact last a lot longer than the dwell time because we certainly feel the ball hit the blade with our hands. So the blade goes BOOOOIIIIIINNNNGGGG! when the ball strikes it and I would guess that the duration of that vibration is mainly how we feel dwell (assuming we really do feel something related to actual dwell, which may or may not be true). That vibration may be impacted by where on the blade the ball hits, the angle of the blade relative to the ball, how hard the impact is and lots of other things.

In answer to someone's question, I personally have no idea how blade composition affects that. Low frequency vibrations are going to be felt as flex, presumably greater with thinner softer wood. It seems like some materials like ALC tend to reduce the high frequency vibrations. I wonder if they also reduce flex in one of the dimensions across the blade so as to give a feeling of larger sweet spot? I am just guessing there. Blade engineers would know. I am sure head shape and size affects that in a big way. Xiom used to make egg-shaped heads claiming it would give better performance. With lots of plies and different types of woods, and all sorts of new composite layers, and also different rubbers -- really really complex.

We definitely hear the ball coming off our opponent's blade, and then we hear it bouncing off the table, and we hear it striking our own blade (unless one is deaf or playing at Spin). I am sure we make a lot of use of that auditory information in various ways, especially for timing, as we play. I am sure it also tells us something about how we just hit the ball, which we can interpret with experience.

I was noticing last night that if I watch a table tennis video with the sound off, it bothers me. I feel like it is harder to grasp all that is happening. I am just guessing, but I don't think that is how we sense dwell. I could be wrong.

Sound is carried through the medium of the air, and we detect it with a specialized organ system that is different from the one we use when our hand feels the ball hit the blade (where the vibration is through the medium of blade itself). From that alone, human sensory physiology is very relevant to the OP's first question. In sensory physiology, the terms hearing, cutaneous mechanoreception and proprioception have very defined meanings. Ultrasound is a vibration through the medium of the air that is at a frequency that exceeds the ability of our auditory system to detect it. It is defined purely in terms of a sensory capability. What is ultrasonic would not be the same for dogs and people and fruitflys. A physicist would just say it is a moving air pressure wave with some mix of frequencies, which are fundamentally the same regardless of what those frequencies are. But to us as sentient beings the frequencies matter because of our physiological limits, which I point out again, is the subject here. Ultrasound is a vibration but not one that matters for the point of view of what we are talking about here because it doesn't come into play in table tennis (because humans can't detect it). I have used those physiological meanings of these terms in all of my comments. I seriously can't see how anyone would have a problem understanding what I have been saying.

 

[Baal]

On another subject, I always thought that a smaller head size makes a blade faster, and the Soulspin web pages also says that.

Is that actually true?

 

[James Livesey]

The very first post on this thread closed with this: "What is the actual cause for the sensation of more dwell?"

One of the first questions therefore entails sensory physiology. Since actual dwell times vary over some range around 1 millisecond or less, we know immediately that the receptors in our hands won't detect THAT. Clearly the vibrations in the blade set up by ball impact last a lot longer than the dwell time because we certainly feel the ball hit the blade with our hands. So the blade goes BOOOOIIIIIINNNNGGGG! when the ball strikes it and I would guess that the duration of that vibration is mainly how we feel dwell (assuming we really do feel something related to actual dwell, which may or may not be true). That vibration may be impacted by where on the blade the ball hits, the angle of the blade relative to the ball, how hard the impact is and lots of other things.

In answer to someone's question, I personally have no idea how blade composition affects that. Low frequency vibrations are going to be felt as flex, presumably greater with thinner softer wood. It seems like some materials like ALC tend to reduce the high frequency vibrations. I wonder if they also reduce flex in one of the dimensions across the blade so as to give a feeling of larger sweet spot? I am just guessing there. Blade engineers would know. I am sure head shape and size affects that in a big way. Xiom used to make egg-shaped heads claiming it would give better performance. With lots of plies and different types of woods, and all sorts of new composite layers, and also different rubbers -- really really complex.

We definitely hear the ball coming off our opponent's blade, and then we hear it bouncing off the table, and we hear it striking our own blade (unless one is deaf or playing at Spin). I am sure we make a lot of use of that auditory information in various ways, especially for timing, as we play. I am sure it also tells us something about how we just hit the ball, which we can interpret with experience.

I was noticing last night that if I watch a table tennis video with the sound off, it bothers me. I feel like it is harder to grasp all that is happening. I am just guessing, but I don't think that is how we sense dwell. I could be wrong.

Sound is carried through the medium of the air, and we detect it with a specialized organ system that is different from the one we use when our hand feels the ball hit the blade (where the vibration is through the medium of blade itself). From that alone, human sensory physiology is very relevant to the OP's first question. In sensory physiology, the terms hearing, cutaneous mechanoreception and proprioception have very defined meanings. Ultrasound is a vibration through the medium of the air that is at a frequency that exceeds the ability of our auditory system to detect it. It is defined purely in terms of a sensory capability. What is ultrasonic would not be the same for dogs and people and fruitflys. A physicist would just say it is a moving air pressure wave with some mix of frequencies, which are fundamentally the same regardless of what those frequencies are. But to us as sentient beings the frequencies matter because of our physiological limits, which I point out again, is the subject here. Ultrasound is a vibration but not one that matters for the point of view of what we are talking about here because it doesn't come into play in table tennis (because humans can't detect it). I have used those physiological meanings of these terms in all of my comments. I seriously can't see how anyone would have a problem understanding what I have been saying.

I would hope that clears it up. case closed? As for smaller head size, I'd say there were three factors: flex, mass, and air resistance. A smaller head size would be more rigid be weigh less. Rigid = faster. less mass = slower. I would have thought that considering both can be controlled with the material make-up, going with a larger head is better because it increases sweet spot. However, there's also air resistance to consider, and i'm not sure how much that affects blade speed and therefore energy output.

 

[ttpshot]

On another subject, I always thought that a smaller head size makes a blade faster, and the Soulspin web pages also says that.

Is that actually true?

If all other factors are equal, I'm not sure.
All I know is that the smaller head size makes a blade lighter which gives faster swing speed thus making it faster looping blade. As James said, larger head size does give larger sweet spot which is the reason it's loved by defensive players but you'd know that already.

 

[Baal]

I am curious if a change in head size would affect that feeling we have of dwell (which may or may not be related to the actual dwell)? Because all things being equal, a smaller racket should flex and vibrate differently after impact with the ball. I am not a mechanical engineer, but shouldn't its resonant frequency be higher (and therefore also any higher harmonics)?

 

[ttpshot]

I am curious if a change in head size would affect that feeling we have of dwell (which may or may not be related to the actual dwell)? Because all things being equal, a smaller racket should flex and vibrate differently after impact with the ball. I am not a mechanical engineer, but shouldn't its resonant frequency be higher (and therefore also any higher harmonics)?

I agree that the resonant frequency would definitely change.
The vibration would also last longer because of less mass thus giving the impression of more dwell?
I'll ask my club mate who works for Butterfy if their R&D records such a data although I'd guess they'd listen to the top players' impression more than data.

 

[Der_Echte]

I am curious if a change in head size would affect that feeling we have of dwell (which may or may not be related to the actual dwell)? Because all things being equal, a smaller racket should flex and vibrate differently after impact with the ball. I am not a mechanical engineer, but shouldn't its resonant frequency be higher (and therefore also any higher harmonics)?

I would tend to agree with Baal on this one. One reason the ALL+ish speed Lissom Oversize has been our best requested special order is the flex on an already great spinner is more with a bigger face, Allround Offensive players like this one.

For similar reasons, I find the BTY Joo S H blade a consistent topspinner no matter what the ball.

 

[Der_Echte]

Hedgehog used to post on OOAK many years ago, he is a Korean blade designer and runs Korea's largest TT forum for over a decade. He designed blades for years, of late I think Adidas and ITC.

He has a company with the expensive frequency analyzing setup to do complicated analysis.

He does reviews mostly in Korean, but a few in English.

I will try to find a few links and post, his insight is very detailed and valuable.

Nexy Korea president also often discusses wood/blade properties on his MyTT/OOAK Diary page.

Oh Crap, Hedgehog is handing over the site to someone in a couple weeks !! He ran that site forever !!

 

[Der_Echte]

It is because 5 ply construction can easily reach the optimum performance.
We may think that 7 ply blades are stiffer than 5 ply blades. But it is not truth.
Of course 7 ply blade gives you stiffer feeling. But it is just the matter of feeling. If the thicknesses of two blades - 5 ply and 7 ply - are the same and the materials are almost the same, 5 ply blade shows higher bending stiffness. But the factor that is concerned with "feeling in hand" is higher in 7 ply blade. :shock:

I am a developer of table tennis blade. I always feel difficulty whenever I am trying to optimize the performance of 7 ply blades. Optimization of 5 ply blade is much easier than that of 7 ply blade. 9 or more ply blades are much harder to be designed.

When we design a blade, we select some typical woods. The main issue is the construction of blade. The orientation of wood fiber is very important. If the orientation is lateral, it affects less on bending stiffness which is the main character of a blade. If will affect the other character that is concerned with feeling. 8)

7-ply blades have too many variables to be controlled, and 3-ply blades have too few variables. But, 5-ply blades can be easily tuned by adjusting the thicknesses of plies and the kinds of woods. :shock:

Of course we can design good 3-ply or 7-ply blades. But, it takes too much time and effort.

1-ply? There is no room to control this construction. If the thickness of 1-ply blade is less than 8mm, it is structurally too weak, and it is too vibrant. Of course we can solve this problem using wood material other than Hinoki. But, we cannot get good feeling and optimal weight from 1-ply blades made of non-Hinoki wood.


Many people think that 5-ply blades are soft and aren't very fast. But, this is just because the majority of 5-ply blades are soft and medium-fast. If we want to make very fast and stiff 5-ply blade, we can. It is even easier than creating fast 7-ply blade. I think there is infinite possibility in designing 5-ply blade.

This is one except from a post he made on OOAK in 2007. He is covering a few issues with blade design, I really wish he would post in the international forums more, his knowledge and experience are exceptional top rate.

He changed all his links on hos site and the old reviews with the diagrams of frequency analysis are gone, but I can tell you he was very detailed.

 

[Der_Echte]

Many people think that soft rubber or soft blade will give more spin, but this is not truth. In general, harder rubbers have more capability of spin. Though the harder rubbers need higher range of average swing speed, even hobby players - not professionals - can get more spin if they try to swing faster.

Sometimes softer rubbers lose more energy than harder rubbers. People think that softer rubbers catch and drag ball well but harder rubbers don't. This is not truth. The catching feeling is just feeling. The real performance is much higher in harder rubbers.

Then why people uses softer rubbers? This is also concerned with feeling.
(I won't tell anything concerned with speed glue because it will be banned soon.)
More important thing is initial speed of rebound. The initial speed of ball leaving rubber surface is slower in softer rubbers. Of course this is the result of loss of energy. But, it gives more control. This enables you to play more aggresive close to table with slower swing speed. The drawback is insufficient spin that you expected.

Another good nugget from Hedgehog from back in the day on OOAK.

 

[UpSideDownCarl]

Here is the experience I have had with Oversized blades. I actually wrote this the other day in a different thread. Here is the same basic info.

I have hit with 2 different oversized blades. One was a Stiga Allround Oversized. And one was a Stiga Clipper Oversize.

Now the nice thing is, the Allround Oversize is the same exact wood as the Allround Classic except the head is 153x161mm as opposed to 150x157mm for the Allround Classic.

The same can be said for the Oversized Clipper vs the Clipper. The wood is the same. The head sizes are the same variance. The Classic Clipper is 150x157mm and the Oversized Clipper is 153x161mm.

The dimensions are from memory from years ago so I hope I have the Oversized numbers correct. But the important detail is both Classic blades have the same head size and both Oversized blades have the same head size. And the wood from Classic to Oversized is the same for each kind.

The Oversized for both of these blades had AMAZING feel. The Classics have very good feel. But the Oversized, the feel was a much BIGGER wood feel and a REALLY good wood feel. Part of me wishes I had one, the feeling was sooooooooo goooooood.

The Oversized version was also noticeably faster, more powerful. Like the Allround Oversized was at least the high end of Off- if not straight up OFF. The effect with the Clipper was similar but not as, "wow, I like this." The two reasons were, the Clipper Oversize was much faster than was fun for me to play with. And the Clipper already starts out as heavy and head heavy. So that Giant Clipper head with a hollow WRB handle was Der_Echte's worst nightmare. [emoji2]

But it still had bigger and deeper feel than the Classic and felt really nice.

The downside to both was the weight and crazy head heaviness. And these things are possibly what caused Stiga to stop making them in spite of how good the Allround Oversized was.

My friend Dave (not a forum member) who came to the goon squad mission at Lily Yip's TTC on New Years 2016, he still has an Allround Oversized in his closet. The reason he stopped using it is his coach said: "Nope, you can't use that blade! It is too heavy for you. Look how slow your recovery time is!" He uses a Butterfly IF ZLF on my recommendation and I don't think there is a better blade for him.

So, from my experience, a bigger head = faster and bigger, deeper wood feel (for a wood blade) but it also = HEAD-HEAVY.


Sent from the Subterranean Workshop by Telepathy

 

[Der_Echte]

My first real blade was a Joola T-Hold White Spot, the largest blade ever made and the softest, slowest thing out there... negative speed rating.

I could topspin with it, even if my head was stuck into my tail crack in terms of technique back then.

 

[ttpshot]

Another good nugget from Hedgehog from back in the day on OOAK.

Very nice!
Has he said anything about balde hardness and spin too? Does the same principle apply to harder blades?

 

[Archosaurus]

@Der_Echte

Your translations of KJH's stuff and now providing us this is just too much.

You're the hero we all want but probably don't deserve. Do keep doing what you're doing.