Measuring wow & flutter

Discussion in 'Brochures, advertising, data & specs...' started by CDV, Sep 4, 2021.

  1. CDV

    CDV Well-Known Member

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    WFGUI, developed by Alex Freed, is a free wow and flutter meter. Its user interface is just a single window, there are few controls, but some options may be confusing.

    [​IMG]
    WFGUI by Alex Freed

    First, select the test frequency: 3000 Hz or 3150 Hz, depending on the test tape you have.

    Choose weighting curve from the dropdown box on the right. The choices are: “Unweighted”, “Wow”, “Flutter”, and, confusingly, “DIN”. This latter option should be called “Weighted wow & flutter” and it is what you should choose if you want to compare your measurements to the numbers provided in equipment specifications.

    IEC and DIN use 3150 Hz tone, while NAB and JIS use 3000 test tone, but in reality the difference makes little effect on the measurements, so you can use a 3000 Hz tone for a DIN test. In fact, the program reports measurements using both DIN and JIS methods simultaneously.

    Play the test tape. Make sure that the signal is strong enough, so that the level meter shows the segments somewhere in the middle of the bar.

    With “DIN” selected from the dropdown, the Peak display, styled as an analog needle instrument, shows wow & flutter in accordance to DIN standard, using quasi-peak detector. The RMS box above it shows values according to JIS standard. Both measurements are weighted. Sometimes they are reported in literature as “W.Peak” (or “Q.Peak”) and “W.RMS” (or “WRMS”), respectively. The JIS value is averaged over a longer period of time, so you need to perform at least half a minute worth of measurements; the documentation for WFGUI recommends discarding the numbers obtained during the first 20 seconds.

    The only time you get unweighted measurements is when you choose “Unweighted” from the dropdown. All other settings are weighted.

    The maximum value box shows maximum peak (which is, in fact, quasi-peak) and maximum RMS value (which is weighted if you chose “DIN”) in the last 10 seconds. If you like pretty graphs, you can turn on the “Save log” option, and then load the resulting log data into a spreadsheet.
    [​IMG]
    Wow & flutter chart by AudioCraft2013

    The above graph shows the WRMS value numerically being about a half of Peak value. This relationship can be tracked through specifications for different machines.


    specs-all.png

    Read the full article on Medium (friend link).
     
    Last edited: Sep 4, 2021
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  2. Longman

    Longman Well-Known Member S2G Supporter

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    DIN is a specific old German standard defining the minimum requirements for HiFi
    https://testhifi.com/2019/01/11/hif...ean-high-fidelity-definition-din-en-iso-ieee/

    Of course nowadays the organisation promoting Digital Radio in the U.K. considers 64KBit/s MP2 to be near CD quality.
     
  3. CDV

    CDV Well-Known Member

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    DIN - Deutsches Institut für Normung e.V. (DIN; in English, the German Institute for Standardisation) is the German national organization for standardization and is the German ISO member body. They make standards, various ones, including specs for audio equipment. What I meant in the phrase you quoted is that the particular dropdown selection is a poor choice, because it does not "turn on" or "turn off" DIN metering - it is always turned on as well as JIS. All it does, it selects weighted wow & flutter curve from four different response curves. Have you read my article on Medium?
     
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  4. CDV

    CDV Well-Known Member

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    I made a video, based on the article. I had to shorten the script by half. Anyway, here it is. Please, use subtitles if you cannot understand my pronunciation.

     
  5. flyman

    flyman New Member

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    Hi. I can't use the software anymore. When I start it shuts down immidiately. Why does it act like this? What am I suppose to do? Thanks in advance for any help.
     
  6. Valentin

    Valentin Well-Known Member

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    This happened to me after a Windows update. It was solved by turning on the "Let desktop apps to access your microphone". See the attached screenshot.
    Without this setting turned on, WFGUI cannot access WASAPI and crashes immediately as it can't detect any audio device.
     

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  7. flyman

    flyman New Member

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    Thanks a lot. I spent my all day trying to figure out the issue. I uninstalled a lot of software which I thought they might be causing conflict with this software. I uninstalled the soundcard driver and reinstalled it, did a cleaning of temp files visa versa..and finally you came to rescue :) I changed the settings now it came back to life. Greatly appreciated
     
    Last edited: May 14, 2023
  8. CDV

    CDV Well-Known Member

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    Huh. MS increases "security", but still rolls out automated updates and collects clients statistics. I am still using Win7 on my desktop, although my laptop came with Win10.
     
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  9. Mister X

    Mister X Moderator Staff Member

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    I had an old version of Adobe PDF Reader Pro, where it had all the advanced functions to edit PDFs, I was trying to use it last week (on a Win7 laptop) and even though I turned all the updating off, Adobe still went in and replaced it with a new version of Reader that doesn't allow editing. I looked it up and it seems they zapped a ton of customers with the exchange early this year. Of course the laptop was running super slow with Adobe turned on (for updates), I think I fixed it and turned it back off but I'm still pissed they erased my program.
     
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  10. Cassette2go

    Cassette2go Well-Known Member

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    Is there a multimeter that I can purchase rather than using this software that would have a frequency counter that I could use with a 3 khz test tape? To adjust the cassette deck speed of the motor?
    I would prefer to have a hardware-based device than to use a software-based device. Can anybody help me in this regard?
     
  11. Valentin

    Valentin Well-Known Member

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    Yes, of course a multimeter can be used to adjust/measure the tape speed. Only disadvantage is, of course, you won't see the W&F but just the speed.
    Any multimeter that can measure frequency in the audio range or above will be able to do this.
    It's to be noted there are some (usually low end, very cheap) multimeters which despite being able to measure frequency they can't do it above 400Hz.
    But any decent meter will be able to do it. For example the old UNI-T UT61 series (E model is still made) or new UT15B are fine for this, no need for anything fancy.
     
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