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

[SIY]

Awesome, thanks! Where do I find the DDPs for RMS drift, wow, and flutter?

They're in the dropdown menu.

 

[JP]

Not in mine. Let me make sure I'm on the latest 3.9.whatever.

 

[JP]

Yup. 3.9.1 -> 3.9.3 fixed that.

 

[JP]

Now I have a new way to obsess

 

[JP]

These polar plots represent 1.8s/rev, 2 revs. I did polar plots at several points along the capture and they all look pretty much the same, so I don't think there is any meaningful variability in what's being sampled. Below each polar is the corresponding numbers from MI. The plot where there's something clearly wrong with the motor gets a much better overall number.

 

[Balle Clorin]

You can also try this WFGUI
A.N.T. Audio :: Welcome :: Library (ant-audio.co.uk)

or WowFlutter Addin in Audacity , and analyse the variations in Rightmark Audio


WFGUI data plotted in excel. %speed deviation vs seconds running a 3150Hz tone form Clearaudio test record. Data form my turntable

 

[Balle Clorin]

A Python script reading a 4 sec .wav file. The Anaconda Python install runs it turnkey, some Python distributions require the advanced math libs to be hand installed. The script is posted a few posts above.

Thanks , but this is all Greek to me. Installed Anaconda and Python, but then I am lost

 

[Balle Clorin]

This is how the "Reference files" from post 1. 0.1% DIN wow flutter looks like when analysed main component at 4vhz and a lot of hash above .
First the 3150Hz tone, then demodulated in Audacity and Rightmark to see the speed fluctuations

And then analysed in WFGUI Wow&flutter free software

 

[edwyun]

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

Thank you. These have helped to calibrate my W&F meter. Does anyone know if there are any similar calibration files in the 0.01% to 0.05% range or lower for weighted/average peak?

 

[VIRTINS]

3150HzModulatedBy4HzAt0.00997Percent0.315Hz.wav

The above one is generated using a carrier frequency 3150 Hz, a modulating frequency 4 Hz, and a max. frequency deviation 0.315 Hz. Its unweighted and weighted peak wow & flutter values are thus: 0.315 / 3150 × sin(0.95×90°) = 0.00997%. Its unweighted and weighted RMS wow & flutter values are thus: 0.315 / 3150 × 0.707 = 0.00707%. It was generated using the signal generator of Multi-Instrument as follows. Calibration files with other wow and flutter values can be generated in a similar way.

 

[edwyun]

3150HzModulatedBy4HzAt0.00997Percent0.315Hz.wav

The above one is generated using a carrier frequency 3150 Hz, a modulating frequency 4 Hz, and a max. frequency deviation 0.315 Hz. Its unweighted and weighted peak wow & flutter values are thus: 0.315 / 3150 × sin(0.95×90°) = 0.00997%. Its unweighted and weighted RMS wow & flutter values are thus: 0.315 / 3150 × 0.707 = 0.00707%. It was generated using the signal generator of Multi-Instrument as follows. Calibration files with other wow and flutter values can be generated in a similar way.

Wow, thank you for this. I was able to create the other calibration wav files. Excellent software tool.

 

[Thomas_A]

Yes, a good TT does not deviate much so it's usually a nice circle. You're welcome to it, JPJ changed the cosmetics at little. You would have to change a few things for large deviations if the distortion gets too great. I also added a text tag for mean speed, don't know if that helps here because the mean is computed over one LP rev. Not sure what OS you use, a free Python distribution like Anaconda has all the libraries you need pre-installed.

Just when I managed to fix the frequency response script I tried the polar plot, but got this error (MacOS, IDLE). Have no clue what the error is.

============ RESTART: /Users/Thomas/Documents/polar plots/Polar plot script.py ============
Tacet.wav
Traceback (most recent call last):
File "/Users/Thomas/Documents/polar plots/Polar plot script.py", line 34, in <module>
y = read(HOME + _FILE)
File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/scipy/io/wavfile.py", line 647, in read
fid = open(filename, 'rb')
IsADirectoryError: [Errno 21] Is a directory: '/Users/Thomas/Documents/polar plots/'

 

[JP]

Just when I managed to fix the frequency response script I tried the polar plot, but got this error (MacOS, IDLE). Have no clue what the error is.

============ RESTART: /Users/Thomas/Documents/polar plots/Polar plot script.py ============
Tacet.wav
Traceback (most recent call last):
File "/Users/Thomas/Documents/polar plots/Polar plot script.py", line 34, in <module>
y = read(HOME + _FILE)
File "/Library/Frameworks/Python.framework/Versions/3.10/lib/python3.10/site-packages/scipy/io/wavfile.py", line 647, in read
fid = open(filename, 'rb')
IsADirectoryError: [Errno 21] Is a directory: '/Users/Thomas/Documents/polar plots/'

Not sure what you've entered but it's trying to open a directory as if it were a file.

This one is setup such that it requires HOME and _FILE:

#edit here to add a HOME directory, etc.
HOME = '/Users/jjones/Documents/polar/'

_FILE = 'FM_WF_SONY.wav'

The IDLE shell retains the environment from the run, so you can interact with it to see what went wrong. In this case we can print the variable to screen and see if it makes sense. Using the config above:

print(HOME + _FILE)
                        
/Users/jjones/Documents/polar/FM_WF_SONY.wav

 

[Thomas_A]

Not sure what you've entered but it's trying to open a directory as if it were a file.

This one is setup such that it requires HOME and _FILE:

#edit here to add a HOME directory, etc.
HOME = '/Users/jjones/Documents/polar/'

_FILE = 'FM_WF_SONY.wav'

The IDLE shell retains the environment from the run, so you can interact with it to see what went wrong. In this case we can print the variable to screen and see if it makes sense. Using the config above:

print(HOME + _FILE)
                       
/Users/jjones/Documents/polar/FM_WF_SONY.wav

Thanks,

I changed the row "_File = input("Tacet.wav")" to "_File = 'Tacet.wav". Still get errors but now also a figure output.

 

[JP]

You’ve a really old version. There is a method that is deprecated that I need to fix - it throws a warning about that.

 

[Thomas_A]

You’ve a really old version. There is a method that is deprecated that I need to fix - it throws a warning about that.

Thanks, I guess there is new version somewhere, but not easy to spot which post it is.

 

[Thomas_A]

I found version 5C, script looks a bit different. It works.

 

[JP]

Weird that the text is overlapping I’ll need to check that. If you do 1k you can change scale to 1Hz/div so the magnitude is the same.

 

[Thomas_A]

Weird that the text is overlapping I’ll need to check that. If you do 1k you can change scale to 1Hz/div so the magnitude is the same.

I think the overlap is because I shrink the window and save.

Q: Is it possible to use integer/rounding for this line to make the scale easier?

myticks.append('{:4.2f}Hz'.format(int(maxf)-(19*Hz_per_tick)+x*Hz_per_tick))

 

[sarumbear]

But why is W&F is a thing in the 21st century?