Stringway Stringlab 2 vs ERT300

[TennisJrDad]

Was curious to see who here has some recent experience with both the new ERT300 and the Stringway Stringlab 2.

In my OCD quest for accuracy and precision in measuring string bed stiffness to track poly string lifespan, I have acquired and have been testing both the ERT300 and the Stringway Stringlab 2. First off, both machines are fantastic and provide consistent and what I consider to be valuable information.

Something I am seeing, which I find interesting, is that the two devices begin to diverge as the string ages and is used. I am curious if this is because one measures actual string bed deflection (the ST2) and the other uses an acoustic vibrational model (the ERT).

For Example:

Reading	ERT300	ST-2
4/26/2023	34	35.03
4/27/2023	32	34.91
4/30/2023	31	34.31

Are there any members here who have tracked results with both? Would love to hear your feedback and observations.

Thanks.

 

[Trip]

I've always just used the app Tennis Tension, which approximate string bed tension (which is different than string bed stiffness, aka dynamic tension) based on a microphone sample that used in conjunction with user-entered head size, string pattern, gauge and material of mains and crosses.

I'd be highly interested to know how much better the ERT300 and/or the StringLab 2 are at giving a more accurate, more easily-repeatable reading. I know the main appeal of the ERT300 is the simplicity and repeatability. Still, without an ability to factor in the additional vectors like you can with Tennis Tension, how accurate can the ERT300 possibly be? Would that make the Stringlab 2 the better buy, as it's actually measuring real, physical string bed stiffness? Or otherwise?

Honestly curious to know as well.

 

[TennisJrDad]

The ERT300 has been very consistent, which I appreciate and value. My only gripe (and it is a minor one) is the display is zero places of precision. Rounding error could cause some variance in readings. It also uses the vibrational acoustic model, which by its very nature is only an approximation of stringbed stiffness. The ST2 actually applies pressure to the string and deflects it and measures the tension. I feel that this should be the most accurate of all measurement methods. I see the same trend in tension measurement between the ERT and the ST2. Right off the stringer, they are almost identical (ERT = 38 ST2 = 37.92). Over time, the delta between the two increases. I am thinking this has to do with the properties of the poly string changing over time and with use which affects their vibrational frequency to a larger degree than their actual stiffness.

Again, would love to hear other peoples experiences and/or opinions on this.

 

[Trip]

As you see a divergence over time, I presume the SL2 will be measuring the more accurate of the two DT values, for, regardless of how string deformation and/or notching may misguide an acoustic sample, a physical depression measurement is much harder to mislead. From your findings, would you be apt to agree?

 

[TennisJrDad]

That is how I am interpreting the results so far.

As you see a divergence over time, I presume the SL2 will be measuring the more accurate of the two DT values, for, regardless of how string deformation and/or notching may misguide an acoustic sample, a physical depression measurement is much harder to mislead. From your findings, would you be apt to agree?

 

[Trip]

Well, I'm kind of glad I've held off on the ERT300 up until now, because, portability issues aside, the StringLab 2 (plus the racquet stiffness add-on) appears to be the better buy.

 

[TennisJrDad]

I like the ERT and think it has its place. It is nice to be able to take when traveling and I find it to be much more stable and consistent than the few different apps I have used. It is also nice as it is pretty hassle free, you just attach it to the strings and get a pretty repeatable value without having to input any other variables. I do think the ST2 is more precise and accurate in the long run through. For my shop, it is becoming the go to device.

Well, I'm kind of glad I've held off on the ERT300 up until now, because, portability issues aside, the StringLab 2 (plus the racquet stiffness add-on) appears to be the better buy.

 

[Trip]

I like the ERT and think it has its place. It is nice to be able to take when traveling and I find it to be much more stable and consistent than the few different apps I have used. It is also nice as it is pretty hassle free, you just attach it to the strings and get a pretty repeatable value without having to input any other variables. I do think the ST2 is more precise and accurate in the long run through. For my shop, it is becoming the go to device.

Bingo. I think that's the best viewpoint of both devices. ERT300 for portability and quick ease-of-use; SL2 as the more stationary, more accurate, in-shop measuring device.

 

[TennisJrDad]

Any other members out here who have experience with both? Would love to hear your point of view and experience.

 

[jmnk]

there's entire thread on ERT device. The principle of its operation is, at best, questionable. Please see this https://tt.tennis-warehouse.com/index.php?threads/ert-300-tennis-computer.725582/post-16765808 and following posts.

 

[Kevo]

Over time as the strings wear material is being removed from the strings through notching and abrasion. It would make sense that it would effect the vibration frequency to some degree. How substantial it is I don't know. I tend to just trust the feel of the strings. I've tried so many over time and especially with polys it seems pretty easy to tell when the start to relax too much and it's affecting your shots. Anytime I can't feel a poly string changing over time from outing to outing, that's a string I consider a contender for regular use.

 

[Trip]

@jmnk - Thanks for that link. That thread is a great read. After dissecting it, I come away with the conclusion that of course no tool, unless that tool is actually pressing a real tennis ball (at newly-inflated 14 PSI pressure) exactly 1cm into a string bed and accurately taking the N/mm / kg/cm measurement, will be perfectly accurate, but that being said, unless I've been lead astray, it seems like the StringLab 2 is the most accurate of all of the devices in question, because even if it is just using a small disk and depressing much less distance than 1 full centimeter, it's at least taking a real, physical depression measurement, as opposed to just taking in an acoustic sample, with optionally-added parameters (such as what you do with Tennis Tension, RacquetTune, etc.), and thus should be able to get closer to a real DT measurement (albeit it's still making an extrapolated calculation, be it logarithmic or what-have-you), both straight off the stringer and as the string bed ages, compared to anything else out there. Would that be a fairly valid take-away? Or are all these machines just about equally worthless in your eyes?

@Kevo - Good points as well.

 

[TennisJrDad]

I think that is pretty accurate. The ST2 is very consistent and repeatable. It is actually depressing the string and measuring force required to move it a set distance. I have found it to be extremely accurate. That bring said the ERT is pretty accurate right off the stringer. Where the variance comes into play is over time it's DT values decrease at a greater velocity than the ST2

@jmnk - Thanks for that link. That thread is a great read. After dissecting it, I come away with the conclusion that of course no tool, unless that tool is actually pressing a real tennis ball (at newly-inflated 14 PSI pressure) exactly 1cm into a string bed and accurately taking the N/mm / kg/cm measurement, will be perfectly accurate, but that being said, unless I've been lead astray, it seems like the StringLab 2 is the most accurate of all of the devices in question, because even if it is just using a small disk and depressing much less distance than 1 full centimeter, it's at least taking a real, physical depression measurement, as opposed to just taking in an acoustic sample, with optionally-added parameters (such as what you do with Tennis Tension, RacquetTune, etc.), and thus should be able to get closer to a real DT measurement (albeit it's still making an extrapolated calculation, be it logarithmic or what-have-you), both straight off the stringer and as the string bed ages, compared to anything else out there. Would that be a fairly valid take-away? Or are all these machines just about equally worthless in your eyes?

@Kevo - Good points as well.

 

[TennisJrDad]

Thanks for the link, interesting reading. Having used the ERT, ST2, and most all of the apps, I have a different take than that thread. I do not think the ERT is flawed in how it arrives at its conclusion. I am pretty amazed how close the values from the ERT and the ST2 are immediately off the stringer. To me that indicates the is validity to the methodology / algorithm that they are employing. The values of the ERT and ST2 diverge in amplitude over time, which I suppose should be expected as one is an actual measurement of string deflection while the other is an approximation via a different process.

there's entire thread on ERT device. The principle of its operation is, at best, questionable. Please see this https://tt.tennis-warehouse.com/index.php?threads/ert-300-tennis-computer.725582/post-16765808 and following posts.

 

[Deleted member 775108]

Was curious to see who here has some recent experience with both the new ERT300 and the Stringway Stringlab 2.

In my OCD quest for accuracy and precision in measuring string bed stiffness to track poly string lifespan, I have acquired and have been testing both the ERT300 and the Stringway Stringlab 2. First off, both machines are fantastic and provide consistent and what I consider to be valuable information.

Something I am seeing, which I find interesting, is that the two devices begin to diverge as the string ages and is used. I am curious if this is because one measures actual string bed deflection (the ST2) and the other uses an acoustic vibrational model (the ERT).

For Example:

Reading	ERT300	ST-2
4/26/2023	34	35.03
4/27/2023	32	34.91
4/30/2023	31	34.31

Are there any members here who have tracked results with both? Would love to hear your feedback and observations.

Thanks.

Hi

Sorry for the misdirection but I thought you wouldnt mind too much.

Have you used the Stringlab to test racquet stiffness? How does it relate to TTW RA readings and your real world feel?

 

[TennisJrDad]

@gold325 I did not get the racquet stiffness testing capability, but again would love to hear from others who did.

Hi @Trip

Sorry for the misdirection but I thought you wouldnt mind too much.

Have you used the Stringlab to test racquet stiffness? How does it relate to TTW RA readings and your real world feel?

 

[Deleted member 775108]

@gold325 I did not get the racquet stiffness testing capability, but again would love to hear from others who did.

Seems like it is only $70 extra - Maybe you will decide it is worth it at some point

 

[TennisJrDad]

Perhaps ... But from my perspective I have very little I can do to change the RA of a racquet, other than replacing it, while it is a much easier and less expensive to replace strings once they have died.

Seems like it is only $70 extra - Maybe you will decide it is worth it at some point

 

[Kevo]

Perhaps ... But from my perspective I have very little I can do to change the RA of a racquet, other than replacing it, while it is a much easier and less expensive to replace strings once they have died.

If I were playing tournaments I would probably pay for it if I were to get a String Lab. I think it would be interesting to know which of my frames are closest to each other in all specs just to have them match as much as possible. It would also be nice to know if a particular frame is wearing out or showing signs of structural damage. For me since I play almost exclusively with old frames I have to source used it would help weed out the bad ones potentially as well.

Of course since I'm not playing tournaments at all any more and often don't even keep all my frames strung with the same string it's kind of a moot point for me.