Wow & Flutter Meter Basics 

UPDATES: 1) 3 KHz vs. 3.15 KHz represent two standards - Japanese Industry Standard (JIS) and Deutsches Institut für Normung (DIN), respectively (Thanks to Rand Grey on Patreon for pointing this out). 2) After reading the manual it appears I may be pressing the Zero button unnecessary - however since it doesn't affect the results in any way, it's irrelevant.

_"Quick extra video"_ * 18 minutes long * This is why I love this channel

Was chilling with my dog watching this. As soon as the 3khz tone played, he left the room in a hurry.

If Techmoan was a school teacher, every single student would pay attention. I know this because I've watched every single upload, even when the subject doesn't *appear* to be interesting to me personally. You always learn something, sometimes have a laugh with the puppets. Great stuff as always.

Flippin 'eck! All that in (almost) one take, you're awesome Mat. Keep up the good work!

gotta love how Mat just put together this video so he can point at it whenever someone asks about it in an upcoming video

Interesting vid. Although throughout the development of sound recording in the 20th century, engineers and the like were always working on ways on reducing wow and flutter (and pretty much achieved it with the advent of digital recording) something may have been lost in the process. Although it's true that excessive amounts of wow and flutter to the point where they become audible can ruin a piece of recorded music, a very small amount may actually be quite desirable. Studio quality master recordings made on well-maintained super high-end tape machines have very little in the way of wow and flutter, but they still have a small amount of what is known as "scrape flutter" - that is, the minor, almost imperceptible speed variations caused by a length of tape being physically dragged across a tape head. I read somewhere that this phenomenon is very similar to the principle of bowing a violin string - the tape, when it "flutters", produces a kind of resonant frequency, which may be one of the factors that contributes to what some term "analogue warmth". That's one of the interesting thing about analogue formats - even on the best turntables or tape machines, the speed variations each time you play something happen in a different place, so in effect, the same piece of music is actually different every time you hear it.

Ahhh, this is brilliant. Having been in electronic testing nearly 30 years, I have used many of the Philips PM series test equipment, which also included a function generator (sinewave, squarewave and triangularwave at various frequencies and voltages), bench multimeters and the suchlike. I knew that they made audio test equipment as well, but have not seen any until now. As a audio enthusiast like yourself, and someone who still repairs old audio kit from time to time, this is cool to see. Typically Philips of the era, simple, understated design and easy to use functionality in a compact case. Wonderful! ☺️

it's friday night and I'm sitting here in my underwear eating an ice cream sandwich and watching a video about wow & flutter meters

~2,000 subs in the same day? (29 during the vid only) Wow!! (no flutter there) Your channel has a lot of quality content, Mat. No wonder.

Just want to take this moment to thank you for all your content , I stumbled across your channel a while back now and genuinely enjoy every video you upload !

Decca record narrated by Jack de Manio, a well known BBC radio presenter.

Thanks, Matt, for another excellent demonstration. When my brother was alive and playing LPs, nothing annoyed him more than when they were off-centre, so he used to file the centre hole out in the correct direction and then check that the edge of the disc rotated evenly before playing it. He was very sensitive to variations in pitch.

Well well well... I am watching your Pioneer CT-50T deck repair and saw this device being used. Searched youtube for it and found this video and had to watch. Great information! In the 70's & 80's I would have loved to have this unit! I had no idea. Thanks a lot!

As far as I remember the 3.15 kHz are actually 3.146 kHz and they were uses as a standard test tone derived from the NTSC horizontal frequency by dividing it by 5. It was used for all sort of audio stuff, since that frequency was generated by a very stable crystal.

A bit off topic but I had an idea a while back to record music to the left channel and a steady tone to the right on a tape in order to correct wow and flutter on playback (with software) I never got around to trying it though. I have however written software to track the frequency, phase and amplitude of a sine wave which I used in a software defined radio project. If you measure the amplitude at 3KHz and also measure 90 degrees out of phase, it makes a quadrature detector, plot it on a constellation diagram (X,Y plot) the angle is phase and the size/radius is amplitude. and if its moving in a circle your frequency is off. The data can be used in a phase locked loop to perform the correction.

Pretty cool watching your subscriber counter going up

You've got to like how thorough this bloke is, really enjoyed this one. many thanks.

Sticky Pinch Roller is a great name for a band

Dougal & Gammer sampled this particular Decca record for their track "3000 Cycles"; I've been looking for the actual original sample for years! Thanks Techmoan!

Wow. I looked at the sub counter in the corner, and didn't realize you were 7/10 of the way to a million subs. I didn't know that many people like this kinda nerdy channel, but you deserve all of them. Hope to see your 1,000,000 sub special soon!

Hi Mat. This was another great video. I would like to point out that the periodical changes in the "Drift" measurement of the test record's tone was almost certainly due to the off-centered spindle hole (A.K.A. eccentricity). Most consumers are not aware of the fact that virtually all records are made with off-centered spindle holes. This is not considered a manufacturing defect. It is allowed in manufacturing standards (one of them is the IEC 98A - International Electrotechnical Commission 98A) which allow for up to 0.2mm eccentricity. So in a nutshell, your interpretation of the Drift measurement for records must allow for up to 0.2mm eccentricity. If you switch the speed to 45 RPM, you'll see the measurement swing correspondingly faster to account for the faster speed. For anyone blessed or "cursed" with the ability to detect absolute pitch by ear, eccentric records will be especially fatiguing to listen to. The only two remedies are to either obtain a turntable with a removable spindle (some record changers made by Dual have this feature) and manually re-center the record through trial-and-error or buy an expensive pre-owned Nakamichi Dragon-CT or TX-1000 turntable that will re-center the record automatically. I went for the first option and the results are great. I don't have the sense of absolute pitch but I do notice that I can listen to LPs for a much longer period of time and I'm sure it relates to the absence of fatigue. Len

When i was a young boy i had a portable cassette player (Grundig CR550 or something) and recorded everything possible on it. Wow and flutter was very "normal" and didnt bother me at all, listening to all the music with so much amount of wow and flutter. Now, 25 years later, i add wow and flutter on purpose in my music, that gives me that extra early 90s vibe.... good old times

I'm an electronics tech in the USAF. From what I can tell this is a distortion analyzer. We use a 1khz tone to check for a signal to noise ratio and distortion levels in radios and accompanying systems. Some systems will filter out a 1khz tone due to it being for testing in that case we use a 1004hz tone if we are trying to test some systems from end to end.

This brings back old memories... Back in the 80s I used exactly this philips wow and flutter meter to repair tape decks...

I remember the 'Wow' of the music, in the olden days, when the phonograph record hole was slightly larger than needed, or off center.

"It's got to get quite noticeable for me to be able to hear it." _Technoman, 2018_

Nice video . For me , only one thing is missing : on the PC application demo , you should have connected the digital 3KHz file as you did on the Analogue Philips Wow/Flutter meter demo , to show that you see the perfect 3KHz wave form on oscilloscope and 0 (zero) Wow and Flutter deviations ;)

Regardless of all the respect You deserve for Your great effort & videos, You have got my biggest respect for Your ( Updates and Corrections ) 🌷🌷🌷

I have that record testing album bought it from a car boot and it helped me set up my upstairs hi-fi as I had the speakers set up wrong. It was well worth the 50p I paid for it.

For a one-take (?) video this really really went well. I know you had ambitions to be on TV one day but you certainly are comfortable with the camera.

That Sony WM-D6C looks immaculate !

I still have that Decca record which once was my fathers, difference being it's in my native language; Dutch. Still remember some phrases lively from when i got explained how stereo equipment works by my father.

It's such a coincidence that you make this video because last night I was watching a video about how ringtones from old bell model 500 phones were recorded in movies and you can tell from the while and flutter as soon as I seen that video I thought of you and here you come out with a video talking about it.

The numbers you're getting off that Walkman Pro are pretty impressive. This leads me to think that you have some kind of weighting engaged in those measurments.

LOL I bought that record this weekend! Listened to it and then found your video for extra info!

Just found that record in a thrift store, but mine is in Dutch. I really love your channel! Thank you for your video's

You've got yourself 29 new subscribers to the channel over the course of this video, keep it up!

I always find the retro sci fi sound effects at the end of these videos to be very soothing.

Dang, I'm really liking the way you lit the closeups of the meter! Looks awesome.

I just love your channel, you’re very interesting to listen to. Thank you so much for all your hard work on your videos! 👍🇨🇦

I keep getting distracted by the subscription counter in the corner. I can't help watching it to see if it changes.

Have you tried taking readings off the RokBlok?

I have a Columbia House copy of a Rush album with a hole that's off center. That's wow.

Would have been funnier if they called it Wibble & WooWoo...

Oh yes, Jack de Maneo. That takes me back. If it is the record I remember it is him and a female presenter. On one band he gravely states, "I am now speaking from the left speaker". While she would announce , "That she was speaking from the right". That could reduce my father to helpless laughter, with the seriousness they gave to the announcement.

Thanks, I checked all my mp3s. They are fine.

That testing record is the gold standard of British accents

Wow is generally a fault limited to turntables when a belt drive has sat too long or stretched. Sometimes the platter bearing grease would set up into a wax that would cause wow. In manufacture of pressed records, sometimes the center hole is punched a little off center on older pressings. If you watch records playing and note the tone arm moves back and forth, this is an off center punched record and this results in wow. Tape decks were the common source of flutter. A dirty capstan, worn pinch roller, failing pinch roller bearings, or drag in the reel drive, back tension brake, all produce flutter. Due to the cost of cal tapes, we used a direct drive tape deck with direct drive reels to produce the cal tapes. In the day you could also purchase a printed strip test tape. This is used to check the drive speed and stability much like a turnable stroboscope. Better turntables had stroboscopes to verify the lack of wow. When the deck was verified accurate, we would record a set of cal tapes using a crystal oscillator to lock a twin T oscillator for a low distortion sine wave. Before running the cal tape the tension tape was run first. It has spring torque meters in the hubs to ensure the tape take up and supply tensions are correct. The test quickly showed faults with supply reel brakes as the ones with mechanical felt brakes would often wear out and the sticky adhesive would contaminate the brake surface. This was a common fault with tape drives which is why I preferred drives with direct drive spools. They didn't rely on friction for tape tension. The low distortion Sine wave was used for playback level calibration and head azimuth alignment. Tapes that get played often tend to stretch and get damaged, so having a box of about 20 tapes for a shop was important. The oldest tape would be used first to check for drive errors, then a less used tape for final test. Often the purchased cal tape was of poorer quality than the in house produced tapes. When a tape started to show degradation, it was tossed. Our shop had a set of 1K and 3K tapes for deck alignments. I used to work in a repair shop and had some time as a radio station engineer. Their carts for jingles news, etc had to be low flutter and on pitch. This was before digital audio. CD's were just starting at the time.

I have no idea why I am watching this but I love it

Very informative and generally makes me feel relaxed. Reminds me of tomorrow’s world. Good work ！

Thank you, that cleared up a few questions I had as I'm just starting to get into this kind of thing.

i actually remember hearing exactly these descriptions of wow and flutter remixed in some hardcore tracks

People nowadays put a WOW AND FLUTTER effect on most lofi songs to enhance the nostalgia of that particular song.

if people think the left meter @ 4:56 was not exactly zeroed its cause of parallax errors (the camera not filming right on top of the display but a tad from the side).

It's satisfying to see 706,000 subscribers exactly on the subscribe-o-meter in the background

That wow and flutter guy is the most proper gentleman Ive ever heard.

I get the 3KHz, but I'm mildly stunned that nobody (to my knowledge) used the tried & tested 1KHz tone or even 400 Hz.

For a 3khz tape you use the JIS standard for measurement, 3000 Hz is 48000 divided by 16 If you use a 3.150khz tape you use the Din measurement, 3150 Hz is 44100Hz divided by 14

I like the point you finally get to. The wow and flutter on the 2 Walkman you would not to be able to hear. People get so nutty over how accurate this equipment over that equipment. The last time,3 years ago I was buying a stereo they guy was doing everything to not let me listen to the unit I wanted with speaker a vs speaker b telling me I need to buy them in sets. For these technical reason and that quality of sound. I point to my ears and said. I am 60 years old, I ware hearing aides do you really think I can hear the difference your talking about? I will buy the speakers that sound best to the hearing my wife and I have. None of the stats mean squat at this point. Your 30 in 20 years from now it will be the same for you unless you just lie to yourself. At my age it is cost vs the quality that I can hear. That’s as good as it gets. Even after all that my kids come home listen shake their hearts and say “ Geez dad you always get the best sound for a reasonable price our whole life’s you’ve always had a bitching stereo system.” I hope there ears aren’t that bad. But I think it proves the point the stats they talk about in the paperwork is just beyond most peoples hearing and understanding. I love your no nonsense practical way of thinking. Good video as always

Anyone notice he gained 29 subs during the recording of this video?

With a digital ocilloscope that has frequency counter built in wow and flutter can be seen by the numbers on the counter decreasing increasing. The better the tape playing device the lower is the difference.

Techmon: "... and as always, thanks for watching!" me: "... and as always thanks for yet another finely made video!" ;-) btw, i see at least 2 objects in the background that are probably exactly the same as the ones i have: 1. a white-bodied DSLR camera ... (what brand / model is it? mine's a super-lovely not so new Pentax K-x that still turns heads around when i use it in public, with some people asking about its price!) :-) 2. a very old yet beautiful Fisher cassette deck player / recorder ... (have had mine since the year 2000 when i bought it in a Goodwill store ... have never used it yet!) :-)

The announcer on 'How To Give Yourself A Stereo Check-Out' sounds like he's just gotten back from the fox hunt and is now about to eat his tea and crumpets.

For checking prerecorded tapes, or maybe even records, a smart machine would also look for the recording bias signal and adjust those variations in. They might blow, but should still be there.

Hey Techmoan, you are not going to believe this, but this is the very first time that I looked at your name closely, I thought all of the time it was spelled "Technoman, I guess I need to wear my glasses more often huh. Anyways I love your videos, and I want to put in a request, would you sometimes in the future do a video on old computers, maybe your first computer and what you liked about it. Would you do a segment on computers of the mid to late 90s. I once owned a Packard Bell legend 1605 Supreme computer. I bought it in 1997. Man, I loved that computer, it was way ahead of it's time. I bought it over at Sears. I bought it as a bundle package. The bundle package included the monitor, keyboard, speakers, mouse, computer, and printer. Yup, all of this came in one big box. I paid $2,500 for it back then. It came with Windows 95. I was fairly new to computer, I swear, if I could find that computer now, and if it was in fairly good condition, I would surely buy it. Techmoan, I will be looking for you to make a vintage computer segment video one of these days. Have a great weekend!!! :-) And yes, your videos ALWAYS get a thumbs up from me. :-)

Maybe the difference in the test tone frequencies are coming from another problem you might want to circumvent: In telephone networks you use a test tone of 8004 Hz. That's because you dont want a tone at the same frequency as your sample rate (usually 8kHz). With 8004 Hz you always have a slight moving "drift" in the amplitude relative to your sampling frequency. Maybe it's the same reason with your meter. I'm not an audio expert, but since 3000 Hz can be divided by both 50 Hz and 60 Hz you might want to have an offset of these 15 Hz to not match the frequency of the power grid.

Matt, as per usual, well done.

It is doable to digitally compute wow and flutter from two recordings of the same test sample on the same device. The test sample doesnt even need to have no wow and flutter - and could be almost anything but some constant noise type could be most convenient. It could be done by crunching wavelets or even more mathemagical gimcrackery.

And now we have vst effects for digital audio workstations that model reel to reel tape including wow and flutter. So you can add hiss, wow and flutter in music that is recorded digitally. Because reasons.

Very well explained and presented.

Techmoan: Maybe You can organize some tours with current audio factories how it is done today. If something sounds interesting for You, it will be interesting for Us ...just the idea for new content series. .I'm sure that You have fans everywhere so to organize access will be a not too big hassle for them :) .. I hope You know what I mean ...I like all You videos :) Regards

As an electronics engineer and enthusiast, I have a frequency generator which can easily produce a digitally derived sine wave upto 24MHz so I'd easily be able to produce a tape for testing at 3KHz but, as you point out, it would entirely depend on the accuracy of the recording deck. I was wondering if the tape used is any thicker than a standard one to reduce stretching over time lowering the frequency of the test signal?

Your channel gained 29 subs during the making of this video.

Your RU-vid counter in the back says 706000, but your subscribe button on the vid says 708K. Keep up the good work!

Wow and Flutter measurements makes more sense if you have one of those 3 head decks, which can reproduce the recorded signal at the same time. So the generator at the Wow and Flutter meter side generates the signal and puts it into the recording end of the deck and the reproduced signal goes back to the meter to read the deviation.

The 3khz test tone is the start to steady dippin, bloods and crips.

I wonder if you could measure the wow/flutter of a tape deck which you use to record and play the 3kHz signal. Of course you will introduce flutter while recording, but if you then remove the tape, spin it a little and put it in again, the recorded flutter should be in a different "position" than the playback flutter. If you do this a few times you should get a minimum and a maximum flutter, kind of like destructive and constructive interference with light or sound. The real flutter should be the average of the minimum and maximum.

Question answered! Was going to ask how can I measure wow & flutter on an old Panasonic RX C45L I’ve just purchased on EBay.

Pro test cassettes are made on a reel to reel duplicator.

I was just watching one of your videos when this popped up lol.

Wow im fluttered. Great explanation.

Everyone is commenting about the price of equipment. I just want to know if he got new glasses. Either way he always looks sharp. Great video and thanks for explaining things.

Perhaps the oddly precise small amounts of wow and flutter on the test record is deliberately put there so you can test your own metering equipment from player known to be accurate. If there were zero values on the record it would be difficult to tell whether your meter was accurately reading zero or insufficiently sensitive to register. You'd think when pressing vinyl it would be fairly easy to produce a precise tone (out of the factory at least).

Perfect and nicely explained ...

every soundcard made in the last 10 years outspecs this thing

Excellent video as always

Wow, if you’ll pardon the pun, I used to borrow a copy of that stereo checkout LP from our local library many years ago! I believe it was Jack de Manio who did the narration?

Try recording the digital signal onto some of your analog devices, then measure the frequency drift. I'd like to see how accurate a high end reel-to-reel tape unit really is.

I love British accents describing things or providing instruction.

I read the video title and I have no clue what to expect in this video. That's unusual. :) I want to listen to the test record on a sunday morning, like it's a John Cage live concert recording.

Quite interesting. I didn't know the little pitch variation had a name.

Trying to figure, if you make your own test tape (for the software): 1. It will not pick up a speed error on the same machine, as it will probably be out by the same amount on record and play 2. Will record flutter and play flutter result in a doubled reading, or will they average out 3. Certain systematic flutter, like the spools dragging at a particular point, may be cancelled out Would be interesting to see how your main recorder scores on a self recorded tape versus the test tape - maybe better due to self cancellation, unless it's close to perfect already.

Thanks for explaining 'Wow & Flutter' so clearly. Now I just need to understand 'Flotsam & Jetsam' and 'Flora & Fauna'! atb snack

Thanks Mat.

The best wow and flutter test record is Meco - Star Wars 45 single It has a constant horn pitch and it is easy to notice the deviation.

Have you thought about using a line-tester for the test-tone? (while their purpose is to test for signal degradation, they need to produce signal(s) that are even purer than your test-tape.) PS: I know of them from a Dr. Who making of, where they told about how they abused them as musical instruments for the original arrangement of the Dr. Who theme.

Interesting ... best review of the basics!!

Good topic. Thanks for the video.

Everytime I hear that Joan Osborne song "What if God was one of us?" I always get the feeling it slows down a little, for a moment, when she starts singing the first verse.