Wow and flutter - some figures

[avole]

Having participated in a couple of discussion recently which have centred on speed stability, aka wow and flutter, I though I'd take a look at a few popular turntables to see what the manufacturer quoted or test figures showed.

Note that the figures refer to out-of-the-box turntables. Belts, motors, bearings all wear over time, so the figures could be expected to deteriorate over time. Also, records themselves can contribute to a poor performance despite what the figures show - nothing like and off-centre hole to ruin the performance of an LP and hence turntable.

Anyway, here are the figures:

Turntable Wow and Flutter Source

CJ Walker CJ 55 0.06% Vinylengine
Linn Sondek 0.03% Reviews
Pro-ject Debut 0.12% Manufacturer
Pro-ject RPM 9.1 0.08% Manufacturer
Linn LP12 0.06% 0.03% (lingo) Reviews
Rega P3 0.09% 0.04% Reviews
MMF5.1 0.15% Manufacturer
MMF9.1 0.15% Manufacturer
Pioneer PL 112D 0.07% Vinylengine
Systemdek 0.09% Vinylengine
Thorens TD160 0.04% Manufacturer
Dual CS505 0.05% Vinylengine
Technics SL-10 0.03% Manufacturer

To what extent wow and flutter becomes a problem is the subject of some debate, so the performance of the worst turntables may in fact be totally acceptable to most. What is interesting, however, are the figures from Pro-ject and MMF, which are worse than the norm. In other words, given that wow and flutter is most noticeable on violin and piano, if you listen to classical music then these would theoretically be turntables to avoid. Whether, however, wow and flutter at .15% is noticeable depends on the listener.

 

[roadtrip]

Deleted

Never mind.

 

[Jody Thornton]

Most of the reading I came across in the 80s were the WRMS or weighted figures. And I found that once they hit 0.04% to 0.06%, that wow and flutter was barely audible, but not in the leat bit objectionable. I found 0.07% - 0.08% reading a little more noticeable on tape decks. To me 0.1 % or higher was where I noticed it to be bothersome.

Again, this was what I noticed - nothing scientific to my findings. I've heard lots of pop music auditioned on a Debut III, and yet the wow and flutter never drew my attention. The pitch seemed stable, and yet I understand it that it's wow and flutter readings are higher.

 

[JohnVF]

They're useful specs but shouldn't overpower the overall impression one gets from listening to the turntable. You can have excellent wow and flutter specs on a turntable that for many other reasons really doesn't sound that good. And while you can't have terrible wow and flutter on a turntable that sounds great, you can certainly have a lot of other positive sonic traits that make up for less than stellar specs in that area. A great tonearm and quiet bearing, for example.

 

[Jeff K]

What is interesting, however, are the figures from Pro-ject and MMF, which are worse than the norm. In other words, given that wow and flutter is most noticeable on violin and piano, if you listen to classical music then these would theoretically be turntables to avoid.

On the other hand, these appear to be some rather stringent and recent tests where - in my quick reading of them - I noticed that most all the Projects passed. There are some surprising fails, as well. (Like a Clearaudio)

http://www.milleraudioresearch.com/avtech/index.html

FWIW, an interesting read. You just have to do a really quick register to view them all.

 

[charliemcd]

Just for grins, here's some wow and flutter manufacturer specs and rough availability dates for a few old tables that I have:

Pioneer PL-518 (DD) 0.03% (WRMS) 1976-1977
Pioneer PL-630 (DD) 0.025% (WRMS) 1978-1980
Sony PS-X6/X7 (DD) 0.025% (WRMS) 1977-1979
Yamaha YP701 (BD) 0.08% 1974

 

[avole]

Interesting comments, all.
It does seem the case that DD will always be better than belt drive when it comes to speed stability, although my DJ deck posts a poor (by DD standards) .15% figure.

I omitted the VPI figures by mistake, but they are interesting if only because they point out the difference in manufacturer's figure versus test lab figures.

VPI Scout .02% (Manufacturer) .09% (Test lab)

One thing I noticed from the Miller Audio Research Figure was how badly Origin Live performed. Both their turntables failed the tests albeit for different reasons.

The Resolution returned figures of .35% for wow and flutter. It failed one of the rumble tests, too. It's only one set of tests, but, given the turntable retails at £2300, it does make you wonder.

 

[4dryhme]

Philips 222(BD) <0.08% wow and flutter.
Rumble < -41dB DIN A
Rumble < -62dB DIN B

$2xx (1970's) $1000+ today

The numbers above need to be muted with the irritating facts that they use those 'plates' for mounting carts and are most obnoxious with the plastic and aren't near worth what I think they should be. Considering the extraneous electronics dedicated to the automatic functions. Yadda yadda, they suck, sell them all to me.

 

[Numistrek09]

My Technics SL-Q2:

W & F 0.012% WRMS (TT assembly alone, no record, cart or tonearm)
W & F 0.025% WRMS (JIS C5521)
W & F 0.035% peak useing IEC 98A weighted
Rumble -56dB IEC 98A unweighted
Rumble -78 dB IEC 98A weighted

whatever all that means

 

[beej]

My Pioneer PL-9 has identical W & F characteristics to Numistrek09's SL-Q2. I'm also not entirely sure what it all means. I do know that I love the sound that my PL-9 produces, particularly when compared to other turntables that I've heard. How much of that is actual difference in quality in the turntable, how the whole system matches up or simply my own preferences for the PL-9 is very much an open question.

My own humble opinion is that none of the numbers mean much if you don't like the way it operates and the way it sounds.

My 2 cents.

 

[GreatTone]

My TT is a mongrel of 70s Japanese parts, with a Sony PSX-6 arm, and a Kenwood KD-5066 drive, which has <0.03% WRMS, and -70dB rumble. I don't know about the numbers, but I can say that the only time the table displays any pitch problems is when the record is off-center, or if it has a particularly steep and nasty warp. Otherwise it's pretty dead on, pitchwise, and I'm very sensitive to variations, it turns out. They drive me crazy.

 

[Dr Tinear]

I found an interesting quote from Edgar Villchur of AR, published in his October 1962 Audio article on the new AR turntable, in which he offered some insights on the usefulness of a raw flutter measurement.

... There appears to be unanimous agreement among academic authorities that raw flutter readings (per cent frequency deviation) have limited meaning until they are qualified by information on flutter rates. All of the writer's experience in development work on the AR turntable bears out this conclusion. The statement that turntable X has flutter of 0.1 per cent and that turntable Y has flutter of 0.2 per cent does not reveal which of the two turntables has better flutter performance. If the 0.1 per cent deviation occurs at a flutter rate of 3 cps, and the 0.2 per cent deviation occurs at other rates, the turntable with the higher raw flutter may have a lower flutter index. Since its flutter has less nuisance value, it obviously deserves a superior flutter rating.

In spite of the above considerations, turntable performance continues to be described in terms of per cent raw flutter. The meaning of this number is easily understood, but it may have little aural significance by itself.

Although the AR turntable does conform in flutter performance to the 1953 NAB Standards of Good Engineering Practice for broadcast equipment, which are in terms of raw flutter, (the flutter measurements yielded results closer to the recording rather than the reproducing figure), the significant production line testing at the AR plant is performed by a weighted flutter meter whose indications take into consideration the instantaneous flutter rates, and are actually in terms of an aurally significant flutter index. This flutter index is a unit somewhat similar to that suggested by the American Standard referred to previously.

... The flutter index in the AR turntable is kept to low values through the use of the simplest possible one-step drive system, mounting of the tone arm for minimum warp wow, machined drive pulley and platen, machined bearings, and possibly most important of all, a precision-machined belt (machined after freezing). Most of these factors are common in turntables in which professional standards are sought.

...

So the type of weighting applied to the flutter measurement is highly significant according to Villchur. This adds one more variable to our discussion to accompany the difference in flutter detection threshold between listeners.

FWIW, the AR XA turntable that I used for years had a flutter spec of 0.03%. The belt-drive Technics that I'm currently using specs out at 0.045%, and to my ears it is as flutter-free as the AR was.

 

[avole]

I found an interesting quote from Edgar Villchur of AR, published in his October 1962 Audio article on the new AR turntable, in which he offered some insights on the usefulness of a raw flutter measurement.

So the type of weighting applied to the flutter measurement is highly significant according to Villchur. This adds one more variable to our discussion to accompany the difference in flutter detection threshold between listeners.

FWIW, the AR XA turntable that I used for years had a flutter spec of 0.03%. The belt-drive Technics that I'm currently using specs out at 0.045%, and to my ears it is as flutter-free as the AR was.

That also applies as to how wow and flutter is measured. There is a big difference between weighted and unweighted, yet few manufacturers specify which ones they are using. It's the same for rumble, where the DIN standards are not used universally.

My feeling is that wow and flutter is important (I've already mentioned the problems with my own deck) and figures offer a valuable guide. At what level you can hear wow and flutter is, however, debatable. My American Audio direct drive cheapie quotes figures of < .015% whereas my Technics quotes .03%, both figures weighted. Can I hear the difference? Sometimes, maybe, when the American Audio has been running for a while - it is a cheap turntable, after all.

Finally, I doubt that many vintage belt drives get close to the figures originally quoted on their introduction. The belt quality, motor wear, bearing wear all have an impact. It's whether we notice that counts.

 

[Arkay]

Here are (manufacturer's) wow-and-flutter specs on some of the best TTs that I have (insert a "less than or equal to" sign in front of each):


Yamaha GT-2000: 0.005%
Pioneer PL-L1: 0.01%
Pioneer PL-C590: 0.025%
Sansui SR-929: 0.028%
Yamaha PF-800: 0.028%


That extra decimal place on the GT-2000 is NOT a typo. It really is in a league by itself.

The first four are DD TTs; the last one, the PF-800, is a belt drive. Its enhanced kissing-cousin, the PF-1000, is rated at a slightly better 0.023%, but I don't have one of those.

While I think a lot more determines sound quality than just wow stats, the above numbers fairly well reflect how I'd rank these TTs sonically, too, with some allowance for differences in arms and carts.

 

[Jon_Logan]

With Wow & Flutter measurements, it's going to be a dynamic number. There's a peak value and a trough value, then there's the mean value that we used to publish as the number. If you plot the wow & flutter over time, you'll see that two wow & flutter numbers that are the same may sound differently. Because the dynamic behavior is different.

 

[Wildcat]

Having participated in a couple of discussion recently which have centred on speed stability, aka wow and flutter, I though I'd take a look at a few popular turntables to see what the manufacturer quoted or test figures showed.

CJ Walker CJ 55 0.06% Vinylengine

Scary...having owned this one since new (mid 80s), I would say the W&F figure is far worse than that. I have fought this turntable since I bought it. Bad belt at first, but a newer one did not help either--not enough torque to drive the heavy platter. I stole a belt from a cheap MMF-2.1 I bought and it could drive the platter, but the speed is still noticeably wavering. I had my Grace arm on a Denon direct drive deck for many years, and I felt that one was not quite as stable as I liked it...but it was still way better than this Walker.

As I read more on the interwebz, I've read that even the motor is not all that good.

I'm debating whether or not to keep this thing or just sell it off, and get something better. That MMF-2.1 had much better speed stability, equal to or even slightly beating the Denon DP-1000 I was using.


P.S. Will trade Walker for one LP-12.

 

[ETI_5000]

Having participated in a couple of discussion recently which have centred on speed stability, aka wow and flutter, I though I'd take a look at a few popular turntables to see what the manufacturer quoted or test figures showed.

Anyway, here are the figures:

Turntable Wow and Flutter Source

Dual CS505 0.05% Vinylengine

I just thought I'd point out that there were four different versions of the Daul CS-505 - it started out in the 1980's (as the first and second versions) as their cheapest model, but by the time of the Mark 4 version, it had become their best model. The figure you've given was for the Mark 1 and 2 versions - the figure for the later and better Mark 3 and 4 versions was 0.035% WRMS.

There are (as the name suggests) two separate sources of speed variation - wow is a slow variation, and occurs at a frequency of between 0.5Hz and 10Hz, so is harder to hear. Flutter is a short term speed variation, and because it occurs between 10Hz and 200Hz, is usually more audible - it tends to cause a hard, unpleasant sound quality if it's too high.

Australian Hi-fi magazine used to say in their 1970's and 1980's buyer's guides for turntables that they considered anything better than 0.2% as an acceptable combined wow and flutter measurement for hi-fi quality turntables, but of course, the lower it was, the better. Their tested figures used to often vary substantially from manufacturer-supplied figures, and it was rare for turntables to get below 0.05% from their calibrated meter, but most bettered 0.1%. Technics turntables were often very good for wow and flutter, which may indicate they had excellent quality control.

 

[marcmorin]

I found an interesting quote from Edgar Villchur of AR, published in his October 1962 Audio article on the new AR turntable, in which he offered some insights on the usefulness of a raw flutter measurement.

FWIW, the AR XA turntable that I used for years had a flutter spec of 0.03%. The belt-drive Technics that I'm currently using specs out at 0.045%, and to my ears it is as flutter-free as the AR was.

AR The Turntable 'production run from 1983-early 89 W/F 0.04%
(manufacture specs) Rumble (weighted) -73db AR ES-1 (84-89) W/F 0.03%
rumble (weighted) -82db.

Some simple tweaks to the The Turntable will bring it to ES-1 levels. Similar tweaks to the ES-1 takes those numbers even further.

 

[avole]

Scary...having owned this one since new (mid 80s), I would say the W&F figure is far worse than that. I have fought this turntable since I bought it. Bad belt at first, but a newer one did not help either--not enough torque to drive the heavy platter. I stole a belt from a cheap MMF-2.1 I bought and it could drive the platter, but the speed is still noticeably wavering. I had my Grace arm on a Denon direct drive deck for many years, and I felt that one was not quite as stable as I liked it...but it was still way better than this Walker.

As I read more on the interwebz, I've read that even the motor is not all that good.

I'm debating whether or not to keep this thing or just sell it off, and get something better. That MMF-2.1 had much better speed stability, equal to or even slightly beating the Denon DP-1000 I was using.
P.S. Will trade Walker for one LP-12.

I agree with what you've said. Part of the problem is finding the correct belt with the correct tension, another part is the three point suspension which seems to have a definite impact if not set up 100% correctly, and the other part the horrible plastic pulley. I've never yet had mine running without a degree of audible wow and flutter, though an age spent servicing the deck and setting up the suspension did seem to help. I'm going to examine the motor mounting next, and also see if I can have a metal pulley machined somewhere.

The motor is meant to be low torque by the way, as in theory it's the heavy platter that keeps wow and flutter to a minimum. Even so, it should be strong enough to start the platter, though I got in the habit of giving it a helping hand.

All that said, it's a lovely sounding deck, and I've heard few better.

 

[KrisM]

Philips 222(BD) <0.08% wow and flutter.
Rumble < -41dB DIN A
Rumble < -62dB DIN B

$2xx (1970's) $1000+ today

The numbers above need to be muted with the irritating facts that they use those 'plates' for mounting carts and are most obnoxious with the plastic and aren't near worth what I think they should be. Considering the extraneous electronics dedicated to the automatic functions. Yadda yadda, they suck, sell them all to me.

I'm still keeping my eyes open for ya. It's cold here today, but I might still get out on my usual Monday route.