Wow and flutter: what is it, and how to measure it using WFGUI?
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- Опубликовано: 5 июл 2024
- 📼 In the world of analog audio, the irregular movement of tape, record or film causes speed fluctuation, which in turn, causes pitch fluctuation. Relatively slow changes in pitch are called wow, faster changes are called flutter. This video explains how to measure wow & flutter using either a hardware or a software meter, and what do the numbers mean.
See a more in-depth written version for more information: reflectiveobserver.medium.com...
Download WFGUI here: www.ant-audio.co.uk/index.php?...
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Chapters:
00:00 - Intro
00:46 - Tape speed, different methods to measure wow & flutter, formulas
03:56 - Wow & flutter measurement with standalone meters and with WFGUI for Windows
This video uses portions from:
BlankFor_ms | TUTORIAL Tape Warble, Wow & Flutter | • TUTORIAL Tape Warble, ...
The LED Artist | Vinyl Strobe LED Outshines Built-in LED | • Vinyl Strobe LED Outsh...
N.H. Crowhurst | The Effects of Wow, Flutter, and Rumble | www.vias.org/crowhurstba/crowh...
Pioneer Electronics | Tuning Fork magazine | No4, 1980
Amalgamated Wireless Ltd. | the instruction manual to A248 wow and flutter meter
Vladimir Kraz | Electromagnetic Compliance: a view from the field | incompliancemag.com/article/e...
AudioCraft2013 | Wow & flutter chart 
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Thank you for the video. I found it difficult to find Wow and Flutter software and you not only provided that, but strengthened my knowledge.
Thanks for the video and link, I've wanted to add a W&F meter to my workshop and this has made it very easy using a laptop and WFGUI. I'll also be considering the simulated Nakamichi T-100 audio analyser software later on and see if it has any more functionality I would benefit from.
Great info. Thanks mate.
Very helpful, thanks.
Great video! I downloaded the WFGUI file, but my version of Windows will not extract it, unfortunately. Any advice there?
For me, on my turntables, I get all OCD if my free RPM Wow & Speed app reads more than 0.1%. But I can't really hear under about 0.17%, except sometimes on certain piano recordings.
Thanks! WFGUI is an executable compressed into a ZIP file (I added the link to the description). There are many un-zippers available for Windows, like 7-Zip or WinRAR. Just un-zip into any directory and run the EXE file. I think the executable is 32-bit, so there should not be any problems from Win95 all the way to Win10. I run it on Win7 32-bit and 64-bit.
thank you
My tape deck is spec'd with peak WTD wow & flutter of ±0.08% and I am reading 0.04% using the WFGUI. Can you explain why the spec uses ± but the meter does not? Are they comparable?
peak WTD wow & flutter a.k.a. quasi peak a.k.a. DIN value. Yes, it is normally spec'd with "±", the numeric value corresponds to the needle in the "Peak" section, and "±" conveys that this is peak to peak value, that is, the difference between two opposite peaks on a sine wave. When you see "WRMS" in a spec or test result, this usually means JIS standard, which measures weighted root mean squared value. If the fluctuations were a pure sine wave, then RMS = 0.7×Peak. In reality, WRMS value is about 0.5-0.8 from peak value. If you are getting ±0.04% Q. Peak, this means that your deck is well within the spec, which is great. If you are getting 0.04% WRMS, it means it is close to the spec, which is good too. Feel free to read the corresponding writeup: reflectiveobserver.medium.com/31cc9495d24?source=friends_link&sk=818921e22a6077799302ae3469ae67d7
Is there a WFGUI or similar program that works for the Mac? I'm assuming this is a Windows only program.
Yes, it is Windows only. You can try running it on the Mac like any other Windows app using virtual machine. There is a native Mac app called NAK T-100 Audio Analyzer that can measure Quasi-Peak DIN 45507 as well as WRMS DIN 45507, although I thought that DIN is always about Quasi Peak, while WRMS is what JIS have used. Anyway, the app is $25, I haven't used it, so cannot say anything about it.
I have a new to me 23 year old tape deck, I recorded the 3300 tone and measured playback at average 1.3%. Since I used the same deck to record AND playback...does the playback measurement reflect a .07 wow and flutter that the original specs specify? The signal was very clean. So, I'm asking, when you record music on a cassette deck, you have to assume that YOUR recordings are going to have twice the Wow & Flutter that the manufacturer would make you think you are getting! RIGHT?
3300 Hz is not a standard tone, it is either 3000 Hz or 3150 Hz, but it should not matter much after all. I am not sure what 1.3% you are talking about, is it the deviation from the ideal tape speed, or wow and flutter measurement? For the former, the deviation within ±2% is considered acceptable, although many tapeheads would tell you that this is too high for them. For reference, 5% change in frequency is one semitone. 1.3% is too high for wow & flutter no matter what method you use.
As for self-recorded tape, I can refer you to the user's guide for the Dynascan Model 1035, which indicates that if you use a self-recorded tape, "one half the measured value represents wow and flutter for playback only". You can see the scan from the corresponding page of the user's manual in the text version of this video on Medium: reflectiveobserver.medium.com/31cc9495d24?source=friends_link&sk=818921e22a6077799302ae3469ae67d7
@@ConsumerDV Sorry, the frequency WAS 3150 hz! So when playing back a self recorded tape, the 1.4 measured percentage is actually double the real wow and flutter because the recording process AND the playback process represent the tape being run twice! Correct?
Also interesting to note that since my unit being a dual cassette deck, I noticed that the frequency on deck 1 played back a bit slower than deck 2. But the wow and flutter were almost identical! By the way, it's an Onkyo TA-RW414 machine from 1994. Thanks for your reply!
According to the Dynascan manual, W&F value obtained with a tape recorded on the machine that is being tested is twice higher than the real playback W&F, which corresponds to your judgement. Other people say that it is *up to* two times higher, because one cannot simply add numbers when talking about sine waves. I am not qualified enough to say which one is correct. Both of these statements agree in that the difference is no more than 2x, so if you measure 0.2% with a self-recorded tape, actual playback W&F is within 0.1%-0.2% range.
Still, I wonder where 1.4% comes from. This value is too high for W&F. Your deck specs show 0.07% WRMS. Maybe you mean 0.14%? There are at least four parameters related to tape speed: (1) tape speed at any given time, which may be different from the ideal one; (2) slow variation of tape speed over time a.k.a. drift; (3) faster variation of tape speed over time a.k.a wow; (4) rapid variation of tape speed over time a.k.a. flutter. The first two are usually combined into one speed/drift parameter, and the last two are combined into wow&flutter parameter. The deck may have incorrect tape speed, but low W&F. 1.4% is ok for drift, but is too high for W&F. According to the old German standard DIN 45550/45511, a hi-fi deck must have no more than ±0.2% DIN Peak, which roughly translates into 0.1% JIS WRMS.
@@ConsumerDV Yes, I redid the test on both decks .14 is correct, as a matter of fact. Using a 30 year old Maxell UDXLII tape, it was a little better averaging .11 roughly. The speed difference between decks is about 1 to 1.5% (assuming the difference between 3000 and 3040 khz is in that neighborhood). I also played the recording on an old Aiwa Walkman, .17 to .20% W/F, test tone frequency was playing at 3140. By the way, I am using a test tone of 3000 khz streaming from RUclips. The frequency counter software shows it at 2999 khz.
How do we connect the audio device to the computer? What kind of cable do i need to use? Thanks
Most laptops have audio in, usually for a microphone, it can be used by adjusting the amplification on the computer and the sound level on a tape machine. For my walkmans I use a 3.5mm to 3.5mm cable. For a component deck I use a dual RCA to 3.5mm stereo adapter.
@@ConsumerDV Thanks for the reply. I think my laptop doesn't support such thing you said. I tried 3.5 to 3.5 but didn't work. But, when i connect a microphone to the same jack on the laptop and my walkman to external speakers, i can read measurements on the wfgui software. Do i need to change settings on my laptop perhaps?
@@ConsumerDV i guess I figured it out. I need to disable mic and see what happens
I would set the volume on a walkman to minimum, connect the cable, start the app, then start the walkman and increase the volume until you see that the level is acceptable. WFGUI shows signal level, I think it changes to green when the level is acceptable.
@@ConsumerDV unfortunately my laptop is a basic one and no line in option whatever i do. I guess i will need an USB sound card. If you have any suggestions for an affordable sound card i can check for it
Nyc