Racquettune.

Irvin

Talk Tennis Guru
Right, it is a question related to the application and how it functions. For RT to determine the tension the only factors driving the performance of RT are the String Factor (That had better be accurate) and the area of the racquet face (which should be accurate from the racquet specification) and not the number of mains/crosses (which appears to be used to calculate the stiffness). If one questions this it is pretty easy to confirm and reproduce this test.
WRONG! If the actual number of strings change the ping sound changes. If you do nothing but change a parameter in RT that is not used nothing happens.

One very important parameter RT uses to determine any output is the ping sound, and ANYTHING that can change the ping sound is included.
 
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LOBALOT

Professional
Irvin I don't think you are following. We are not talking the racquet we are talking the application.

The point is the application could care less if you typed that there is 1 main or 7000 mains and all one needs to do is to try it out and confirm like I did. The application does not care what is entered for the string parameters in order to determine the tension.
 

Irvin

Talk Tennis Guru
Irvin I don't think you are following. We are not talking the racquet we are talking the application.

The point is the application could care less if you typed that there is 1 main or 7000 mains and all one needs to do is to try it out and confirm like I did. The application does not care what is entered for the string parameters in order to determine the tension.
If you are not talking about how RacquetTune works maybe you're in the wrong thread.
 

LOBALOT

Professional
Reproducing this is not difficult.

1. Grab Any Racquet you want.
2. Set up a racquet called "Test 1" in RT using the actual number of mains, crosses, and area for the racquet
3. Assign the appropriate string to "Test 1"
4. Ping the racquet you grabbed in step 1 as many times as you would like and write down the tension.
5. Set up a racquet called "Test 2" in RT using a different number of mains and crosses than what you entered in Step 2 but use the same area as you entered in Step 2.
6. Assign the same string to "Test 2"
7. Ping the racquet you grabbed in Step 1 as many times you like and write down the number.

One will observe the tensions produced will match in RT which tells us that RT doesn't care how many mains/crosses are entered in the app.
 

brady1212

New User
what do you think RT uses to determine tension
Seems like based on what he is saying it uses 3 methods to determine its value. 1) String Factor value 2) The frequency the string bed makes when you hit it 3) The head size of the racket.

If these 3 values mentioned above stay the same, the output of racquettune will always be the same regardless if you put 16 x19 or 18 x20 or 54 x50 for the string pattern. Now I haven't verified this myself, but seems pretty clear to me what he is saying.
 

Irvin

Talk Tennis Guru
Seems like based on what he is saying it uses 3 methods to determine its value. 1) String Factor value 2) The frequency the string bed makes when you hit it 3) The head size of the racket.

If these 3 values mentioned above stay the same, the output of racquettune will always be the same regardless if you put 16 x19 or 18 x20 or 54 x50 for the string pattern. Now I haven't verified this myself, but seems pretty clear to me what he is saying.
Every time you use RacquetTune there are 4 outputs. Tension in kg, tension in lbs, stiffness in N/mm, and frequency in Hz. Garbage in garbage out.
 

Karma Tennis

Hall of Fame
The Android version I use does not label them "String 1" and "String 2".

It simply has two sets of input fields both labelled "String". I've always associated the first set of fields with the Mains and the second set with the Crosses. Perhaps I will switch the values around but I don't think it will make any difference.

Anyway, does it really matter. All said and done, you string a racquet at a certain tension or DT. You want that reading off the stringing machine. So if you have to manipulate the input values to product the correct reading when testing the racquet, you do that. You still have to strike the physical string bed to get the reading. And from that point onwards, you strike the same stringbed to take further readings until it is time to restring that racquet.

So while the input values could actually be "Garbage In" as @Irvin puts it, it will produce a "Garbage Out" result without aligning the input data to a real tennis racquet with a real string bed that produces a real sound when struck by a real object.

So that means RT uses ONE thing to measure the physical stringbed ... and that ONE thing is .... the Frequency of the sound produced when the stringbed is struck.

(As an aside, I'm thinking about a 24 x 24 string pattern. How about a very thin Poly string (say 22 Gauge). Uber control with plenty of spin potential.)
 
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Rabbit

G.O.A.T.
@LOBALOT - I am a programmer by training and profession. Let me clarify. Garbage In Garbage Out (GIGO) was an old adage used in textbooks and it became popular like "bug". However, what GIGO really meant was to warn programmers to edit their input. If they didn't, then a) the program would abnormally end (ABEND) or b) you would get "unpredictable results", i.e. garbage.

What you're saying, if I've read correctly, is that the input fields mentioned are not critical to the process used in racquettune. And, truth be told, they may not be used in the calculation at all. They may simply be used to produce the string database kept by the application. So, in short, you and the others are right. If you change the field level input----mains and crosses----and nothing else then there is the greatest probability that mains and crosses are not used in the determination of dynamic tension. They are simply used as document fields for a database being maintained by the application. Just like borrower name and SSN have no bearing on a loan payment calculation. The fields that do are interest rate, term and principal.

I hope this helps in some small way, but I don't think it will to some.
 

LOBALOT

Professional
Hi Rabbit, I think we discussed in the past that I am an old programmer too. I am very familiar ABEND although being a UNIX programmer in the past encountered more core dumps than I would have liked ;).

What I am saying is that Irvin's GIGO response is also incorrect. In this case it is not garbage in garbage out. From what I am seeing (and anyone with the app can confirm), the number of mains and crosses is irrelevant to the tension reading RT produces. It is not garbage, it simply doesn't mater to the tension reading.

It is kind of like if you asked me what is it like outside and I respond. "It is 90 degrees, the sun is out, I am driving a blue car." The fact that I am driving a blue car doesn't mater to an understanding of what it is like outside.
 
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Rabbit

G.O.A.T.
@LOBALOT - exactly right, you and I are simpatico. My loan amount example was exactly like yours. The fields mains/crosses are descriptors for later use by a human, not the application.

And I had forgotten you were a programmer..my bad! I am currently working iSeries and having to do stuff with UNIX (yuck!). I have also picked up Python of late and am in geek love. :)
 

Karma Tennis

Hall of Fame
It is kind of like if you asked me what is it like outside and I respond. "It is 90 degrees, the sun is out, I am driving a blue car." The fact that I am driving a blue car doesn't mater to an understanding of what it is like outside.
Doesn't sound like you guys are Australian.

In your example, the colour of the car matters a great deal if you are tying to impress your boss or a prospective romantic interest.
 

LOBALOT

Professional
@LOBALOT - exactly right, you and I are simpatico. My loan amount example was exactly like yours. The fields mains/crosses are descriptors for later use by a human, not the application.

And I had forgotten you were a programmer..my bad! I am currently working iSeries and having to do stuff with UNIX (yuck!). I have also picked up Python of late and am in geek love. :)
UNIX is awesome actually once you get going at it. Seriously, you can do so much with it. I have been a PM for 25 years now so miss it but still dabble in VB Script when I have the opportunity to clean up some data as I can't get too far from my roots. My undergrad and grad is actually electrical and computer engineering.

Anyway, I think RT captures the mains/crosses because it uses that along with the string tension and the area of the racquet face for the stiffness measure but do not have a basis for this statement. What I was able to see for myself is that it does not use the # of strings to calculate the tension from the tone.
 

esm

Hall of Fame
Doesn't sound like you guys are Australian.

In your example, the colour of the car matters a great deal if you are tying to impress your boss or a prospective romantic interest.
That is probably because Oz is so far away from the rest of the world and not much else happening in the land of down under. Lol
 

Rabbit

G.O.A.T.
@LOBALOT I’ll take your word on UNIX. I’m an IBM mainframe guy— z/VSE & z/OS now winding things down doing conversions from MF to the iSeries and loving it.
 

Karma Tennis

Hall of Fame
That is probably because Oz is so far away from the rest of the world and not much else happening in the land of down under. Lol
What? So are you saying that people in America and Europe don't care what colour their cars are?

That would explain why so many European and American cars in Australia are either White, Black, Grey or Silver ! A lot tennis PJs seem to be going the same way too.
 

Irvin

Talk Tennis Guru
What? So are you saying that people in America and Europe don't care what colour their cars are?
White or black cars make a big difference when they sit in the sun when it’s hot outside. Just like heated and air cooled seats.
 

esm

Hall of Fame
What? So are you saying that people in America and Europe don't care what colour their cars are?

That would explain why so many European and American cars in Australia are either White, Black, Grey or Silver ! A lot tennis PJs seem to be going the same way too.
i'd say the colour of the car is rather personal, but not at a great deal as you called it.
i don't remember the colour of the car was such a great deal when i was growing up in/buying cars Oz though....
i think the colour white is making a big come back on the cars though, lol
anyway, back to topic - when i string up a racquet next time, i will play around with the number of mains and crosses in RT and see what the readouts are 8-B
 

esm

Hall of Fame
@esm - no care package from @uk_skippy -- day 39.

I used to be of the Henry Ford school. I buy any color car as long as it's black. My next one will be white though.
oh no, day 39 already - i was going to ask you about that, but didn't want to put too much pressure... lol
will, i think white is the new black, i am sure Mr. Ford wouldn't mind.
 

jim e

Legend
@esm -

I used to be of the Henry Ford school. I buy any color car as long as it's black. My next one will be white though.
One of my older cars is black, an old Dodge Challenger. A black car looks great when all cleaned up, but it it difficult to keep it that way. I don't think I will ever get another black one again, as I go for colors that are easy not to show the dirt so much.
 

esm

Hall of Fame
One of my older cars is black, an old Dodge Challenger. A black car looks great when all cleaned up, but it it difficult to keep it that way. I don't think I will ever get another black one again, as I go for colors that are easy not to show the dirt so much.
my previous and current cars are black. you are right, it looks great when clean/polished... but shows dust/dirty super quickly.
my fave colour is orange and i have had some or my cars resprayed in orange colour when i was young and "stupid"... lol
i think i'd go for a lighter colour for the next one.... either the classic silver or metallic white.... or whichever has the best spec and best discount :laughing:
 

Rabbit

G.O.A.T.
One of my older cars is black, an old Dodge Challenger. A black car looks great when all cleaned up, but it it difficult to keep it that way. I don't think I will ever get another black one again, as I go for colors that are easy not to show the dirt so much.
Yeah...I started this obsession with a '89 Mustang GT 5.0 Convertible in black, then an '04 Inifiniti G35 6 speed in black and now a '13 Lexus GS350 in black. The Lexus has the best paint job ever, and it looks great when clean. What year is your Challenger? I wanted one ever since I saw Vanishing Point back in the day -- in Kowolski white! I test drove one with a 5.8L V-8 and it didn't seem as peppy as my Inifiniti....I was a bit disappointed. The Lexus doesn't handle as nimbly as the G35, but it hauls ass in Sport Mode.
 

jim e

Legend
My Challenger is a 1974, rallye model, the last year of that model. Got the car in 1974, as it was a Chrysler executive car, and as such I was the original titled owner. My college car, and kept it .
 

Karma Tennis

Hall of Fame
White or black cars make a big difference when they sit in the sun when it’s hot outside.
@Irvin, Australia is in the Southern Hemisphere. So Black coloured cars are much cooler here than White ones are.

We also drive on the right (LEFT!) side of the roads here, so that enhances the effect. When we stand by the roadside, the cars passing closest to us come into our field of view from the right and pass to the left ... just like reading a book!

It's like stringing tennis racquets here ... we always sting the crosses first starting at the throat and working our way up to the top. Mains are then strung from the outside to the middle.

And we use the European version of Racquettune rather than the US one. Priority is given to Kgs rather than lbs. (Interestingly though you guys still call it Racquettune rather than Rackettune even though the measurements are achieved by making a racket with the racquet!)
 

esm

Hall of Fame
My Challenger is a 1974, rallye model, the last year of that model. Got the car in 1974, as it was a Chrysler executive car, and as such I was the original titled owner. My college car, and kept it .
Looked that car up and that is so cool.
I think it’d look good in any colour.
 

Rabbit

G.O.A.T.
My Challenger is a 1974, rallye model, the last year of that model. Got the car in 1974, as it was a Chrysler executive car, and as such I was the original titled owner. My college car, and kept it .

I am GREEN with envy. The Challenger was the car I always wanted (still do actually). You have a Challenger, live on a lake -- you may be my hero!
 

Karma Tennis

Hall of Fame
The Challenger was the car I always wanted (still do actually).
Dodge had plans to import Challengers to Australia as a competitor to the Mustang from this year but it has been scotched due to COVID.

The SRP was going to be at least TWICE the SRP (IN USD !!!!) of the equivalent model in the USA. (Costs a lot of money to convert from LHD to RHD and conform to Australian Standards. Also add freight costs, import duties, and add Sales Margins.)

There is one for sale in Australia atm. A 2019 Hellcat SRT model that has been properly converted. The asking price is around $220K AUD (approx $160,000 USD at current exchange rates.) Should I make an offer? :unsure:;) (For comparison purposes, the full spec. Mustang is nearly half the price.)

Except for a very brief period about a decade ago when the AUD and USD were parity, Australia always gets shafted when it comes to the pricing of anything including cars and tennis gear :(
 

Karma Tennis

Hall of Fame
@Karma Tennis the Mustang is pretty bad ass. I’d probably opt for it.
Where I come from an "ass" is another word for "donkey".

But these are bad ARSE ! ...




The most famous Pony Car in Australia is this one ...


I don't know what any of his has to do with Racquettune though.
 

RayPS97

New User
The String Material is inherent in the String Factor. Yes, they have us enter the mains and crosses but it is not used to calculate the tension. It is used to calculate the stiffness.

As an experiment one can test a tension with 16x19 and then 18x19 and then 18x20, etc. and see the tension does not change for a given racquet.

Note, the number of mains and crosses at a given tension across a specific area of the racquet face is related to stiffness. I suspect that is why the number of mains and crosses along with the area are being requested.
Back to the farm where us curmudgeons roam ... :rolleyes:

There is a white paper published in by Rod Cross in 2001on which RacquetTune is based. The linear density of strings (i. e. the weight per length), area and resultant frequency give a simple equation for the tension.

The author of RT originally posted info, here, about new releases and mentioned adding the capability to estimate the SBS (stringbed stiffnessI or pounds to depress an inch) to RT.

I ran a test today where I took a recording of a 16x19 string bed being struck and put it in a loop. Rt measured 47.6 pounds (599 Hz). I duplicated the setup but doubled both mains to 32x38. Tension reported was, no surprise, identical in both setups. However, the SBS went from 33.7 pound/inch to 45.5. A 35‰ increase at the same tension.
 
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Irvin

Talk Tennis Guru
I ran a test today where I took a recording of a 16x19 string bed being struck and put it in a loop. Rt measured 47.6 pounds (599 Hz). I duplicated the setup but doubled both mains to 32x38. Tension reported was, no surprise, identical in both setups. However, the SBS went from 33.7 pound/inch to 45.5. A 35‰ increase at the same tension.
What you’re saying is true. Changing patter as long as you keep the area the same in theory should result in the correct tension but the wrong stiffness. OTOH changing the area and maintaining the same string patter will do the opposite. The problem is putting bad data in RT accomplishes nothing so there is no advantage to to do it. Inputting the wrong pattern or string bed area could result in RT not recognizing a good quality reading or discarding the reading and not giving you an output at all. Inputting bad data also pretty much makes the share function useless. GIGO
 

Karma Tennis

Hall of Fame
correct tension but the wrong stiffness
Don't you mean "same tension and different stiffness"?

When I string, I always aim for the same DT reading off the stringing machine. I would think that "stiffness" is a much better indication of the racquet's playability than tension is!

As an example, I strung three different types of racquets (95 16x20, 97 16x19, 100 16x19) with the same string at the same tension. As expected, the DT values off the stringing machine were all different. The player noticed the difference between the racquets at ball impact.

Then I experimented and adjusted the Ref tensions when stringing each racquet to produce the same DT off the stringing machine. The player noticed much less of a difference between the racquets at ball impact.

It was also more valuable to track the reduction in DT values over time for each different racquet.

So in this case, the Ref tensions were only important in that they are the guide to producing a repeatable DT value for each racquet.
 

Irvin

Talk Tennis Guru
Don't you mean "same tension and different stiffness"?
No I meant wrong stiffness, assuming you put in the wrong string pattern. If you change the pattern from 16x19 to 30x30 it will result in the wrong stiffness not just a little different. GIGO
 
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Karma Tennis

Hall of Fame
No I meant wrong stiffness, assuming you put in the wrong string pattern. If you change the pattern from 16x19 to 30x30 it will result in the wrong stiffness not just a little different. GIGO
I don't understand what you mean.

Afaik, a DT of 36 is a DT of 36 is a DT of 36 .... the string pattern is irrelevant if one is aiming for a particular DT

IE ... I want a DT of 36 ... I know that my particular racquet and string will achieve that if I string it at 23kgs. (If I string a different racquet, I might have to use a different Ref. Tension to achieve a DT of 36.)

RT caculates the DT based on the freq. of the sound produced when the string bed is struck.
 

Irvin

Talk Tennis Guru
@Karma Tennis you are correct. But when you set up a racket in RT you enter the head size and pattern and RT uses those inputs and sound to determine the tension, stiffness, and DT. Why would anyone want to put in bad pattern or head size data? If I string 2 630 cm^2 rackets one being a 16x19 racket and the other an 18x20 at 55#, I would expect the the tensions to be different and the DTs to be different.

OTOH if I input the 16x19 racket as a 30x30 racket RT is not going to give me a correct output because the input was wrong. Same thing with the head size. Bad input result in bad outputs if that data is being used to calculate the output.

There is no good reason to put bad data in RT for a racket.
 

Irvin

Talk Tennis Guru
@LOBALOT what you’re saying is true, but not practical. If I create a 24x24 fictitious racket there is no way to test it because it doesn’t exist. So I would have to measure the tension is what I tell RT is a 24x24 racket with a 16x19 racket. RT uses head size and sound to determine tension (Reference - see RT guide Racquet section.) The sound is determined by pattern and ref tension. Therefore no matter what you tell RT the string pattern is the only parameters used to determine tension is sound and head size. For example, in the 2 rackets I strung yesterday the both had the same head size 630 cm^2 but different patterns. The tensions used to string them were fairly close. I just measured the frequency of both string beds and found a 33 Hz difference. That sound is used to measure tension and stiffness. Putting erroneous data that isn’t used into RT does not change anything.

Big difference though if you’re talking about stiffness. For stiffness RT uses the pattern and sound and not head size.

Most people have issues with RT because they cant understand it. It is normal that the tension you get from RT is NOT the same as reference tension. They see a different reading and automatically assume it just can’t be right. That’s why more often than not I suggest people just use the frequency rather than tension. I think tension in a strung racket is very misleading because most users do not understand it.

it is impossible to measure the forces applying tension on a single string by tapping a string bed with multiple mains and crosses interwoven together.
There is no good reason to put bad data in RT for a racket.
Sure there is, to determine if those inputs have any effect on the final outcome which is exactly what everyone has been trying to explain to you.
There is no reason to create a racket that does not exist and test a 16x19 over and over. The sound from the 16x19 will remain the same except for any tension loss over time. If the guide tells you the only thing that matters is head size and sound I would believe it. Unless you a tester trying to brake the app why put in bad data?
 

Rabbit

G.O.A.T.
There is no reason to create a racket that does not exist and test a 16x19 over and over. The sound from the 16x19 will remain the same except for any tension loss over time. If the guide tells you the only thing that matters is head size and sound I would believe it. Unless you a tester trying to brake the app why put in bad data?
If you are trying to determine if head size and string pattern have any effect on the dynamic tension in the application, sure there is. If you change them and the output doesn't change, then they do not have any effect, plain and simple. That's all @LOBALOT was trying to do. Both @LOBALOT and I are in IT. We test computer applications for a living. This is how you test. It could not be simpler. You have have assumed that everything is considered which based on @LOBALOT 's test isn't true.

Why have the two fields then? Because those two, combined with main & cross string and diameter help build a database of strings the user can reference. As per my example: when you take out a loan, they ask for your name and address. Neither of these data items have any consideration in your payment amount, ergo they are not used.
 
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