Wow and flutter measurements

[Addicted to music]

Just reading this article and realised you can make these measurements on a phone App….

Not sure on an Android but definitely on an iPhone that has 2 Apps available.  
 

https://www.headphonesty.com/2025/04/vinyl-fans-smartphone-apps-shame-turntables/

 

Then this is followed up by where else but here:

 

https://www.audiosciencereview.com/forum/index.php?threads/wow-and-flutter-measurements-like-youve-never-seen-before-maybe.54866/
 

Anyone done this?  Just for a bit of fun it be interesting which phone App you used and what the results are on what TT you have.   

 

[aussievintage]

I use this one

 

https://play.google.com/store/apps/details?id=com.AM.AM.RPMSpeed&hl=en-US

 

Edited April 5 by aussievintage

[SonicArt]

I have that app and "turntable speed" which has more resolution, or appears that way  

I regularly see 0.03% on the Oracle, have seen 0.02% on one I rebuilt a while ago, I save the readings in the app.

I have even gotten a Rega P3 down to 0.07% and a P6 down to 0.05%. My custom made TT with rim belt and Origin Live motor, rebuilt early model OL controller with different chips has gotten down to 0.02%.

[marcusD]

I find the phone apps to be variable in their results compared to a fully calibrated unit like a shaknspin. The rpm app does have a graph that is useful for looking at bearing performance, but the W&F readings and speed accuracy are questionable 

[aussievintage]

2 hours ago, marcusD said:

I find the phone apps to be variable in their results compared to a fully calibrated unit like a shaknspin. The rpm app does have a graph that is useful for looking at bearing performance, but the W&F readings and speed accuracy are questionable 

 

Might depend on the phone, but I find my speed measurement agrees with a strobe disc and with a handheld optical device that measures RPM.  RPM is a averaged timing thing, so even an inaccurate magnetomoter in the phone will still be able to measure speed, as it's the timing, not the strength that matters.

 

edit:  actually, the wow and flutter is similarly based on speed (variation), so again, the accuracy of the magnetomoter chip doesn't matter.  It's more about the timing measurements.  I winder if they use the clock chip, or just do it programmatically.  If the latter, then close all other apps etc, maybe put the phone in flight mode to improve accuracy.

Edited April 5 by aussievintage

[cafe latte]

44 minutes ago, aussievintage said:

 

Might depend on the phone, but I find my speed measurement agrees with a strobe disc and with a handheld optical device that measures RPM.  RPM is a averaged timing thing, so even an inaccurate magnetomoter in the phone will still be able to measure speed, as it's the timing, not the strength that matters.

 

edit:  actually, the wow and flutter is similarly based on speed (variation), so again, the accuracy of the magnetomoter chip doesn't matter.  It's more about the timing measurements.  I winder if they use the clock chip, or just do it programmatically.  If the latter, then close all other apps etc, maybe put the phone in flight mode to improve accuracy.

Phones are not calibrated, but Shaknspin are, every time it is used.

I have tested several phones against Shaknspin and for speed or wow and flutter they never agree with the Shaknspin. Also speed wise the Shaknspin shows my Sl1200g and my SP10MK2s to be correct but the phone shows them as slightly wrong.

Another issue with phones is they put the platter out of balance which messes with the wow and flutter, a Shaknspin does not.

A phone app is a bit of fun, a Shaknspin is a real tool you can accurately measure what your turntable is doing 

Chris

[aussievintage]

29 minutes ago, cafe latte said:

Another issue with phones is they put the platter out of balance

 

Agree, except for this.  I put mine balanced on the flat top of a record clamp/weight right in the centre.

[aussievintage]

On another note,  if you find the reading on a phone to be consistent - i.e. it reads the same, or close, every time you take a measurement without changing anything else, then it is still a very useful tool for you to use to verify any tweaks you may make to the turntable.

[SonicArt]

Put it on a puck or similar, pointless to put the phone on one side of the platter. I sit it on an OL Gravity puck, dead centre. The speed may not be absolutely spot on, but once you compare to a strobe and know what the phone reads it translates across any table you measure with the same phone. Use a puck high enough so you can play the record while checking speed to see if you have any variation.

 

Oh and to be clear, I see this discussion as for the average user/reader here, not everyone is going to spend $500 on a tool to measure their TT speed, some might have less than that invested in their TT, so while I agree purpose built tools are the most accurate best way to go, lets not end up belittling people about using phone apps or any other method...

Edited April 5 by SonicArt

[aussievintage]

 

Interesting reading on the net about accuracy of a phone in timing applications.  Seems they can in fact be quite accurate. for example  https://pmc.ncbi.nlm.nih.gov/articles/PMC8498103/

 

So I guess it's down to the programming of the particular app used.

[marcusD]

1 hour ago, SonicArt said:

Put it on a puck or similar, pointless to put the phone on one side of the platter. I sit it on an OL Gravity puck, dead centre. The speed may not be absolutely spot on, but once you compare to a strobe and know what the phone reads it translates across any table you measure with the same phone. Use a puck high enough so you can play the record while checking speed to see if you have any variation.

 

Oh and to be clear, I see this discussion as for the average user/reader here, not everyone is going to spend $500 on a tool to measure their TT speed, some might have less than that invested in their TT, so while I agree purpose built tools are the most accurate best way to go, lets not end up belittling people about using phone apps or any other method...

Wasn’t trying to belittle people for using phones, just pointing out their limitations as an accurate device. I make a lot of TT components so the calibrated accuracy has some value to me

[marcusD]

13 hours ago, SonicArt said:

I have that app and "turntable speed" which has more resolution, or appears that way  

I regularly see 0.03% on the Oracle, have seen 0.02% on one I rebuilt a while ago, I save the readings in the app.

I have even gotten a Rega P3 down to 0.07% and a P6 down to 0.05%. My custom made TT with rim belt and Origin Live motor, rebuilt early model OL controller with different chips has gotten down to 0.02%.

here is a dirty old Commonwealth 12d4 I just serviced for a client 

[SonicArt]

6 hours ago, marcusD said:

Wasn’t trying to belittle people for using phones

wasn't aimed at you or anyone in particular, simply putting it out there before the thread potentially got heated.

I too fabricate a lot of TT parts.

[cafe latte]

2 hours ago, SonicArt said:

wasn't aimed at you or anyone in particular, simply putting it out there before the thread potentially got heated.

I too fabricate a lot of TT parts.

If you fabricate turntable parts and you want to really know what is going on a phone is not going to cut it.

Chris

[Warren Jones]

I also use a Shake n Spin which is has the facility to download the data to a spreadsheet and graph stability and speed variation. This functionality is particularly useful for anyone repairing/modifying turntables.

 

The benefit to using a device on the platter is it not only measures W&F but total platter stability.

 

I have used a couple of phone apps (Android) and they IMO are not up to the task I need, all Android version only measure WOW not W&F.  These phone apps are fine for anyone looking at a quick verification totally useless for me building my own TT's and bearings.

[Warren Jones]

Here are a couple of measurements. Level of detailed information is invaluable to improving the bearing on my highly modified inverted bearing SP10. Look how stable the speed vs time plot is. W&F WRMS = 0.000, but more importantly I see PEAK W&F has decreased indicating a much more stable platter.

 

Standard Technics SP10

 

 

 

Modified Inverted Bearing SP10 the next 2 

[marcusD]

5 hours ago, Warren Jones said:

Here are a couple of measurements. Level of detailed information is invaluable to improving the bearing on my highly modified inverted bearing SP10. Look how stable the speed vs time plot is. W&F WRMS = 0.000, but more importantly I see PEAK W&F has decreased indicating a much more stable platter.

 

Standard Technics SP10

 

 

 

Modified Inverted Bearing SP10 the next 2 

Nice one @Warren Jones, looks like you have got that humming along real well

[cafe latte]

On 06/04/2025 at 9:02 AM, aussievintage said:

 

Agree, except for this.  I put mine balanced on the flat top of a record clamp/weight right in the centre.

I have tried doing this ages ago ie balancing a phone on some sort of puck. It works but only to an extent as the phone is not round and one end is not the same weight as the other.

When I was doing this I found it a very frustrating exercise, moving thr phone mms and trying again with changing readings.

The Shaknspin is the same time and time again.

Chris

[e83cc]

On 8/4/2025 at 3:37 PM, Warren Jones said:

Here are a couple of measurements. Level of detailed information is invaluable to improving the bearing on my highly modified inverted bearing SP10. Look how stable the speed vs time plot is. W&F WRMS = 0.000, but more importantly I see PEAK W&F has decreased indicating a much more stable platter.

 

Standard Technics SP10

 

 

 

Modified Inverted Bearing SP10 the next 2 

Can you please advise are these measurements taken whilst a record is playing or are they taken with no load ( stylus drag ) ?

[Warren Jones]

On 09/04/2025 at 4:05 PM, e83cc said:

Can you please advise are these measurements taken whilst a record is playing or are they taken with no load ( stylus drag ) ?

 

Those measurements are no load.

 

These measurements were taken on my previous version directly from the motor feedback FG both no load and playing Pink Floyd Eclipse. The loaded difference is extremely small 0.008WRMS

 

No load

 

Playing Pink Floyd Eclipse.

[Gieseler Audio]

Still got this stashed away somewhere