Turntable Wow and Flutter "Polar" Plot Script

[JP]

This script creates polar plots from wow and flutter test tracks. I'll provide more background information on it later. The current "released" code is below.

EDIT: The script code is now located at https://ttpolarplot.com

 

[JP]

Reserved

 

[JP]

Reserved

 

[JP]

Reserved

 

[Chrispy]

Uh, why?

 

[thegeton]

Uh, why?

Why did OP reserve 3 sequential post entries, or why do a TT W&F polar plot?

 

[ban25]

Interesting. I have a belt-drive table that has pretty severe W+F and another direct-drive table that is flawless. Will have to take a measurement this weekend to compare.

 

[JP]

There was no audio data for that revolution - file isn’t long enough.

 

[Balle Clorin]

Clearaudio has a test record with a 15 minute 3150Hz track.. here is 100 revolutions on that on a belt drive, yes it had drift that day... DC motor no tachometer control.

Clearaudio Trackability Test Record 180g LP

Elusive Disc, Inc., Features Only The Best In Audiophile Hardware, Accessories and Music. We Offer a Wide Variety Of Audiophile Turntables, Cartridges, Phono Stages, Record Cleaners, SACD Players, Speakers, Headphones, Pre-Amps, LP Cleaning Fluids, Cables, Vibration Control, Record Brushes &...

elusivedisc.com

I found my error I have to have L&R file, single track does not work

 

[JP]

It should detect mono - that part hasn’t changed for years.

 

[morillon]

Clearaudio has a test record with a 15 minute 3150Hz track.. here is 100 revolutions on that on a belt drive, yes it had drift that day... DC motor no tachometer control.

Clearaudio Trackability Test Record 180g LP

Elusive Disc, Inc., Features Only The Best In Audiophile Hardware, Accessories and Music. We Offer a Wide Variety Of Audiophile Turntables, Cartridges, Phono Stages, Record Cleaners, SACD Players, Speakers, Headphones, Pre-Amps, LP Cleaning Fluids, Cables, Vibration Control, Record Brushes &...

elusivedisc.com

View attachment 327712


I found my error I have to have L&R file, single track does not work

?
have you identified the problem on the record or turntable side?

 

[Balle Clorin]

Wow and Flutter. Cannot remember , old file. The WF track is not very good, + I may have adjusted the speed too.

Here is a new recording today 30 revolutions B&K QR2010 on Michell Gyro SE, belt DC motor

The best I have seen so far,

it even beats the w&f in this video for Technics top TT with the DS Audio ES-001 Eccentricity device…

I am not saying my TT is better than the Technics, but the test record limits the accuracy. Test records can only be used very carefully or else the results are misleading

 

[mfalcon]

@JP I'm getting the below error

/Volumes/NAS/plots/wow and flutter/polarplot.py:96: UserWarning: set_ticklabels() should only be used with a fixed number of ticks, i.e. after set_ticks() or using a FixedLocator.


ax.set_xticklabels(['90'+u'\N{DEGREE SIGN}','45'+u'\N{DEGREE SIGN}','0'+u'\N{DEGREE SIGN}',\

I'm using Python 3.11.7.1. The OS is MacOS 10.13. This is my regular Python installation.

It's weird, I have like a minute of audio but it plots two revolutions, and locks up after throwing this warning. Then I have to control-c to get out of the terminal. Have you seen anything like this? Thanks in advance.

 

[JP]

That's just a warning - benign. If you're using the non-beta code it'll only plot two revolutions.

 

[mfalcon]

@JP I started using the beta. Still get the warning but also good plots. Now if I can find a good test record for W&F.

thanks for all your work

 

[JP]

There's no really good test records, and different pressings means there aren't even known good matrix numbers necessarily. One method you can use to separate what is the record from the 'table is to zoom in to something in the waveform that can "index" the start of the track, and two a second plot with the record rotated 180deg on the platter.

 

[n3mmr]

It seems the script assumes one complete turn takes precisely (60/33⅓) = 1.8 seconds.
Isn't that a bit trusting?
If you get enough data, and you know the nominal frequency you should be able to calculate a more exact real time for one rev, or?
Or did I miss something in the script?

 

[JP]

The nominal f being bang-on is rather trusting as well.

 

[Balle Clorin]

The nominal frequency is off too sometimes, or most of the time ..

 

[n3mmr]

The nominal f being bang-on is rather trusting as well.

Exactly, but the nominal frequency will tell you what the effect of a deviation will be on the rev time.

But if the nominal freq is X Hz, and the real frequency measured is Y Hz, then the one-rev time for 33⅓rpm nominal is (X/Y)*(60/33⅓) seconds