Wow, Flutter, W&F, weighted and unweighted, JIS/DIN/CCIR and NAB. Help me!

[restorer-john]

OK, you know me. Standards are important, as is measuring to them.

Until recently, I have just trusted my Wow and Flutter meter, although I always wondered how accurate it was and particularly the application of the weightings to the various standards.

Enter the National Association of Broadcasters flutter meter calibration files I have uploaded here:

https://drive.google.com/drive/folders/1Gc6fW5l_sdhvBK6bhiaHzcHx_VW8Xa_7?usp=sharing

The DIN files are DIN 3.15KHz standard frequency modulated to give 0.1, 0.3 and 1.0% when set to measure DIN weighted peak flutter on a properly calibrated flutter meter.

The NAB files are NAB 3KHz standard, frequency modulated to give 0.1, 0.3 and 1.0% when set to measure NAB average weighted flutter on a properly calibrated flutter meter.

I called them NAB/JIS simply because the JIS standard also uses 3KHz and the WRMS (weighted RMS) on Japanese specs. This was incorrect of me it would seem as the NAB standard is different. In exactly what, I don't know. @Frank Dernie , Can you clarify this? Is it the same except RMS vs MEAN? And do you have a W&F meter?

So, whoever has a proper wow and flutter meter can download and check the flutter functionality of the meter's calibration according to NAB standards and report back with their findings. Perhaps @amirm or @SIY can employ their AP's W&F utility and give some comparitive numbers- particularly the weighted/peak/average?

 

[restorer-john]

Here are the 6 tracks tested on the Kenwood FL-140 W&F meter.

First three in sequence

Second three in sequence

Clearly, it doesn't need any calibration (not that you could find anyone these days to do it..)

What I don't quite understand is the readings are absolutely spot on on all ranges and the two standards in the W&F position, but the flutter position gives readings well under the W&F readings...

 

[SIY]

So, whoever has a proper wow and flutter meter can download and check the flutter functionality of the meter's calibration according to NAB standards and report back with their findings. Perhaps @amirm or @SIY can employ their AP's W&F utility and give some comparitive numbers- particularly the weighted/peak/average?

I'll try this two ways...

 

[SIY]

OK, you know me. Standards are important, as is measuring to them.

Until recently, I have just trusted my Wow and Flutter meter, although I always wondered how accurate it was and particularly the application of the weightings to the various standards.

Enter the National Association of Broadcasters flutter meter calibration files I have uploaded here:

https://drive.google.com/drive/folders/1Gc6fW5l_sdhvBK6bhiaHzcHx_VW8Xa_7?usp=sharing

The DIN files are DIN 3.15KHz standard frequency modulated to give 0.1, 0.3 and 1.0% when set to measure DIN weighted peak flutter on a properly calibrated flutter meter.

The NAB files are NAB 3KHz standard, frequency modulated to give 0.1, 0.3 and 1.0% when set to measure NAB average weighted flutter on a properly calibrated flutter meter.

I called them NAB/JIS simply because the JIS standard also uses 3KHz and the WRMS (weighted RMS) on Japanese specs. This was incorrect of me it would seem as the NAB standard is different. In exactly what, I don't know. @Frank Dernie , Can you clarify this? Is it the same except RMS vs MEAN? And do you have a W&F meter?

So, whoever has a proper wow and flutter meter can download and check the flutter functionality of the meter's calibration according to NAB standards and report back with their findings. Perhaps @amirm or @SIY can employ their AP's W&F utility and give some comparitive numbers- particularly the weighted/peak/average?

Disclaimer: this is the first time I've run the AP W&F. I have a different method that I'll also use to see if this is repeatable or just error on my part. In any case, I ran the 1% files with DIN and JIS, weighted and unweighted. Here's screenshots of the results:

So significant difference between DIN and JIS, but not much between weighted and unweighted. And to repeat, this is my first time using this utility and any errors could be mine.

 

[Frank Dernie]

I don't know. @Frank Dernie , Can you clarify this? Is it the same except RMS vs MEAN? And do you have a W&F meter?

Sorry, can't add anything. All the instrumentation I used belonged to Garrard. I also left there to go full time F1 motor racing in 1976 and went back to being a hobbyist again.
I would like to know how my rebuilds of my turntables effect the W&F but I only do it every 5 years or so and only for myself. I don't play records a lot so not worth sourcing a meter.
If I am honest I don't remember W&F measurements as much as rumble, probably because the method used gave data without much effort whereas separating environmental effects from real data was a challenge for W&F.

 

[restorer-john]

Disclaimer: this is the first time I've run the AP W&F. I have a different method that I'll also use to see if this is repeatable or just error on my part. In any case, I ran the 1% files with DIN and JIS, weighted and unweighted. Here's screenshots of the results:

That's really interesting. Thanks so much for doing this.

I had thrown out my unweighted results as they didn't make sense to me. I figured the weighted numbers hit each mark perfectly on each standard so the meter was accurate. The trouble is, all these years I've misinterpreted the usefulness (or lack thereof) of the separate wow and flutter functions on these Kenwood meters. My Leader always gave the same readings, so I figured they were both right. (when you don't have access to calibration and certification, my solution was multiples to compare to each other- flawed I know, but...)

It seems that the FM modulation in these NAB calibration test samples affects the wow and the flutter not just flutter, as my individual flutter function seemed inconclusive on these cal samples. Are these demodulated sidebands affecting wow and flutter and separating them for this purpose is pointless? Quadrature FM demodulation and Hilbert transforms etc, were never my thing...

Here's the spec of my meter:

It easily resolves to 0.002% on the 0.03% FSD scale.

 

[restorer-john]

I would like to know how my rebuilds of my turntables effect the W&F but I only do it every 5 years or so and only for myself.

Thanks Frank.

You can post a W&F track anytime on ASR and we can analyze it for you. @JPJ has his polar plot which I think Scott W had a hand in developing.

 

[JP]

That was all Scott.

 

[JP]

I have a different method that I'll also use to see if this is repeatable or just error on my part.

MI?

 

[SIY]

MI?

Yes. I have the latest version.

 

[JP]

Played with that but wasn't sure if I was getting sane numbers. Also seems record and cutting eccentricities are easier to weed out with an analog meter, or polar plot.

 

[SIY]

Played with that but wasn't sure if I was getting sane numbers. Also seems record and cutting eccentricities are easier to weed out with an analog meter, or polar plot.

The nice thing about both the AP and MI is that you can get a spectrum so these issues can be sorted out.

 

[JP]

Alright, I'll play with it and see if I can learn something.

 

[SIY]

Played with that but wasn't sure if I was getting sane numbers. Also seems record and cutting eccentricities are easier to weed out with an analog meter, or polar plot.

First try with the JIS 3kHz track, I got 1.4% unweighted from MI. Not exactly the same, but reasonably close.

 

[JP]

This weekend - left the license dongle at the house and leaving for Vegas in the morning.

 

[SIY]

You know we're only a 5 hour drive or a 45 minute flight from Vegas... just saying.

 

[JP]

I did consider that. Timing for this one wouldn’t have worked.

 

[SIY]

Damn your eyes!

 

[restorer-john]

First try with the JIS 3kHz track, I got 1.4% unweighted from MI. Not exactly the same, but reasonably close.

But miles away from the 1%. Have you tried the other tracks, the 0.1% and 0.3%?

When running the AP's W&F utility, do the analyzer settings (on the dashboard) come into operation on a direct file playback or are they bypassed by the utility?

Can you play the files on a D/A and send the analog input to the AP and compare?

I've always been curious to know if the software based W&F analysis gave the same figures as properly calibrated instruments but never had an official way of checking either my meters' accuracy or anyone else's. So far, it's not looking good as far as correlation. For the record, my meter has never been touched since new, and yet it indicates the exact numbers on these 6 cal files...

 

[SIY]

But miles away from the 1%. Have you tried the other tracks, the 0.1% and 0.3%?

Not yet. During the week, I only have a few minutes now and then at the bench. Having to work for a living really gets in the way of fun stuff.

When running the AP's W&F utility, do the analyzer settings (on the dashboard) come into operation on a direct file playback or are they bypassed?

They are active.

Can you play the files on a D/A and send the analog input to the AP and compare?

Sure, I could try that. I may or may not be able to pull that off with their utility.