Direct Drive turntables

Mike, Raul,
Actually, the 0.001% Raul quoted is equal to 10 parts per million (it already has the percent sign there). Lots of Japanese DD tables had a 10-20 parts per million speed accuracy spec (at least using the most advantageous measuring method), but those tables which also had a quote for speed drift limitations generally allowed a lot more speed drift than that. I expect that the Rockport, along with the P3 Shane has, and some of the other expensive motor tables, limited allowable drift to about that level as well, and then used a variety of methods to reduce the speed/violence at which deviations were brought back to normal (i.e. platter mass, a drag function, torque attenuation (P3 has a torque attenuator circuit), etc).

" most of us do not have sufficient pitch sensitivity to detect a 1% error..."
This would refer to 'Perfect Pitch' detection

"our ears are remarkably sensitive to extraordinarily small deviations..."
And this would be 'Relative Pitch', which many more people have.

Inherent speed stability is one of the indisputable side-benefits of high inertia (i.e. high platter mass - raw mass....).
Stylus drag - while still kind of a nebulous issue - is best addressed by securely clamping, pressing (by means of clamp (sic..), peripherical ring, vacuum - whatever suits you best) the record onto the platter thus that there is no relative movement of the record to the spin of the platter while the stylus moves its way through the groove.
In any case speed accuracy as well as stability should only measured "in action". By following this routine stylus drag won't be any issue any more.
Here again the old principle to avoid the error in the first will always give superior results to correcting the error after it occurred.
In any case - on any turntable: as long as the record has any chance for a relative movement to the spin of the platter, there is no way to discuss speed stability, stylus drag or dd vs. belt/thread, idler wheel drive.
As long as the record isn't clamped down it is all an "orchestra manoeuvre's in the dark".

Dear Dertonarm: As is usual in almost all your posts you talk,talk,talk,... on different subjects where you use some times technical language or like in your last post in this thread what your thoughts/guessing are..

Your last post states: +++++ " as long as the record has any chance for a relative movement to the spin of the platter, there is no way to discuss speed stability, stylus drag or dd vs. belt/thread, idler wheel drive. " +++++

where is/are the controled tests that can confirm that movement of the record relative to the spin of the platter if we don't use some clamp mechanism? where we can be sure that that record movement even exist? with which TT platter build materials? with which cartridges? which kind of set up on those cartridges: VTF/VTA, etc.. ?, which differences between 33rpm and 45rpm? how affect the different recording velocities at which each record track was recorded? which differences are on the subject with 200gr/180grs/120grs Lp weights? where affect and how at out side grooves, middle ones an inner grooves? which TT mats were used ( if any ) on the controled tests? is there any " enviroment/stage " where with out a clamp mechanism there is no record movement? which one?

+++++ " there is no way to discuss speed stability, stylus drag or dd vs. belt/thread, idler wheel drive " +++++

why? because you say so?

IMHO your guessing is only that a guessing ( that can or can't be true. ) with out no foundation if you can't or don't answer at least all those questions with scientific controled tests that can speaks by it self.

I always use some clamp mechanism, from a simple clamp/dead weight to vacuum hold down system. Well, in the last few months I don't use any kind of clamp any more, either in my DD and BD TT's, with surprising results for the better. In all this time I don't detect any single problem that is related of what you posted.
Btw, any one of you can make the test in your system with out using any clamp tool looking for a related problem because no clamp ( movement record relative to spin of the platter. ).
You can find other kind of " problems " because no clamp but I seriously doubt you can find the " problem " that dertonarm put on the table.

Btw, somewhere in some thread I posted my " controled " ( not very scientific ones. ) tests about that cartridge drag with different TT's, different cartridges, different stylus shape, different VTF and even with one, two, three and four cartridges running at the same time: my conclusion was that I don't have to worry about.

Now, if you have all those controled tests then bring here and share with all of us. Honestly I hope you have it because that could be a great information where almost all of us will learn about.

Regards and enjoy the music,
Raul.

Well Raul, sure I am talking in my posts - otherwise they wouldn't exist - but certainly not to the length you are going to. What I have mentioned in my last post are issues and matters which should - due to their simplicity and plain objectivity of facts and their interrelations - be so obvious that they do not need discussion nor controlled tests the way you put it.
None of us has to re-invent the wheel. None has to proof again that our planet encircles the sun. In this audio world there is no such thing clear nor proven enough not to be questioned by some.
That you do not use any kind of clamp anymore - and many others do likely - is certainly not my problem nor does it proof or disapprove anything. Its just a personal preference based on your taste, preferences and the special individual matrix of your hearing.
Just like with everybody else's.
It all comes down to personal preferences and opinions which you have mentioned too again and again.
Hearing and the experience of "sound" in human brain (which is the place where it actually takes place...) is a most individual and not to be quantified nor qualified sensation.
My remarks about trying to come as close as possible to a point where platter and record do form one single mass was purely technical-wise.
The physical benefits in the playback process are so obvious that - sorry - this is far beyond any serious discussion from my point of view.
But of course, you will - and are most welcome to do so - as always have a different opinion. Fine with me.
Enjoy the long journey,
D.

They are not as common because they are more expensive to do well these days as someone indicated early on.

I'm skeptical of any inherent benefits of DD to the average home record listener over other drive approaches. It ain't rocket science to get a table to spin at constant speed and there are lots of ways to do it cost effectively. ISolation from motor or other external vibrations is trickier.

For good sound, better to focus on matching a good cart to good arm and phono pre-amp optimally.

Dear Dertonarm: +++++ " That you do not use any kind of clamp anymore.... " +++++

I don't posted to say any one is wrong or something, just like a " datum " but forget about it is not important as is the post subject.

++++ " be so obvious that they do not need discussion nor controlled tests the way you put it. " +++++

useless to follow: is so obvious!!!?????.

Regards and enjoy the music,
Raul.

Mapman, Spinning a platter at an average speed of 33.3333 is very easy. In fact it is fairly easy to get the accuracy to 4 or even 5 decimal points (not that it matters much). The problem is making it constant at a microscopic level, or at least to a level below audibility. This part is very difficult and in some ways at least as difficult than rocket science.

Isolation from the motor is all about constant speed. Motors vibrate primarily because the torque they deliver is not constant. The uneven torque translates into speed instability and speed instability (even tiny amounts) translates into degraded sound.

My experience with turntable drive systems has convinced me that speed stability is one of the most important, and challenging parts of turntable design. I have to admit that this finding was surprising to me so I understand your skepticism.

All,
I currently use a highly modified Rockport Sirius I TT with a 50# stainless steel platter and constrained layer damping driven by an external motor, oversized power supply, aramid fiber belt. The motor uses a flywheel, the platter a vaccuum draw down. I have experimented extensively with the vaccuum on and off and with an ancillary Lurne record clamp used in conjunction with the vaccuum hold down. In my system, I have concluded that the vaccuum hold down always results in better sound, even with flat records; however I doubt that the reason has anything to do with record slip/stylus drag. I say that because the sound even with the vaccuum engaged further benefits from the use of the Lurne clamp. I would note that Andy Payor bonds a proprietary material to the top surface of the stainless steel platter which he feels better interfaces the record with the platter and that the vaccuum is necessary to maximize the coupling. Prior to the Rockport, I owned both a Goldmund Reference (belt) and a Goldmund Studio (DD). I will note that the tables sounded very different with the same arm (T3F) and cartridge; however, I will not try to ascribe these differences to the differring drives mechanisms. Too many other design choices were different. I will note that the reference was not superior in all ways to the Studio and that both benefitted significantly from the use of the Lurne clamp in place of the Goldmund Reference clamp. I will say that my empirical conclusions based on many years of listening tend in many areas to align with those of Dertonarm, but that I also have great respect for Raul who has visited my home and listened to my system in its current configuration.

It never ceases to amaze me how many audio nuts propound theories without data. And when folks ask for data usually the answer is it's too complex to measure or we measure the wrong thing. Or, it's so obvious that no testing is necessary.

Are you really saying that none of you physics guys can figure a way to measure a) slippage due to stylus drag and its effect on dd versus bd, b) the similar effects of a vacuum and spindle clamp, and c) the constancy and behavior of the hypothesis that belt drive slippage averages a high mass platter even in the instance of variable amounts of stylus drag? Last, nobody has attempted to measure human sensitivity to pitch (speed) variation relative to the duration of measurement? If I were a manufacturer, I could turn a kitchen daisy wheel at exactly 33.3 if you gave me enough time to manipulate it.

FWIW, I vote that agon creates a science first forum where opinions must be backed by data (or references thereto).

I agree with Raul in this case and he makes some salient points about 'evidence' or lack thereof vs theoretical postulations.
I also think it 'big' of him to recant as I seem to recall that up to a year or so ago he was a keen supporter of clamps?
What Daniel claims is 'theoretically' correct (and obvious)........if there IS slippage between record and mat/platter it puts the subject "beyond any serious discussion from my point of view".....however Daniel fails to provide evidence of ANY slippage let alone extent or magnitude?

There are many turntable manufacturers who specifically discourage the use of clamps on their designs (Linn, Rega, Raven).
There are also designers who advocate vacuum hold-down as well as clamps (Rockport, Continuum) whilst others recommend clamps but not vacuum hold-down (Walker).
I have heard all these designs and if 'clamping' and 'bonding' were essential to prevent 'slippage' of the record, then you would think its effects would be obvious in the resulting sound differences and ALL great turntables would have in common, their use of vacuum hod-down and clamping?
In my experience this is not the case.
For 30 years I have had a Rega Planar 3 followed by a Raven AC-3 and neither turntable sounds better with a clamp.
As Raul confirms.......one doesn't need to 'calculate' the effects of clamps vs no clamps? One need only listen.
Those turntables specifically designed with vacuum hold-down and clamps will no doubt sound poorly without them but those designed with the opposite philosophy will not necessarily sound better with their addition?

As usual in this hobby, 'absolute statements' rarely withstand scrutiny?

FWIW, I vote that agon creates a science first forum where opinions must be backed by data (or references thereto).

there are lots of forums where 'prove it' is dominant. in those forums few focus on listening, and it's interesting how the 'sceintists' rarely if ever post about listening experiences. they focus on why this or that cannot be true because of their expertise. and pretty quick 'listeners' find another forum.

it is a personal decision whether to trust one's ears. i'm not passing judgement on anyone else's way of looking at things. but having to 'prove it' with data is not my idea of a good time. it's fun to compare perspectives on the basis of listening to music. and if it's not (or when it's not) fun then i'm gone, i deal with facts 6 days and 55 hours a week.

i'm not anti-data. measurements have a place in their service of the art (music). i think the balance of posting perspectives here on AudiogoN is healthy. if someone gets off track there is feedback questioning that perspective. do we sometimes ignore science? i would hope so.

that said, if someone wants to do a bunch of measurements and present them no one is stopping them. knock yourself out.

If you Dont like to clamp or vacuum but like the lp to stick you can use glue(preferrably removable glue). My guess is the slippage Will be less even though i havent qed.

Just to expand on Mike's comments...

I am reminded of Theodore Leavitt's remark that "People don't want a 1/4" drill, they want a 1/4" hole." I want to listen and enjoy music in my home; the equipment is simply the means to the end. I could care less if the TT is DD, belt or idler, nor do I care if I'm listening to solid state or tubed equipment, through horn, dynamic or planar speakers...I just want to connect with the artist and enjoy their art.

We haven't even begun to address the most important components: our ears and brain, i.e. how we are uniquely wired to interact with music. My son who has true perfect pitch, can not be in my music room if my TT's absolute speed is not spot on 33 1/3 rpm, but he is not affected by small speed variations. I'm exactly the opposite...go figure.

Having been lucky enough to have visited Mike's listening room (aka Vinyl Disneyland) on many occasions, his Dobbin's plinthed Garrard is my favorite source in his room...on most LP's. However, on some recordings, I prefer the Rockport.

Does anyone think that there is meaningful math or science that can explain this??? Anyone who knows me can tell you I'm an extremely data and numbers driven person, but this is a place where subjectivity rules. IMO, measurements are useful in guidance, i.e. don't buy a 2W SET amp if your going to use 85dB efficient speakers, but the only thing that really matters is how the equipment meets your individual requirements to connect with the musicians.

"but this is a place where subjectivity rules. IMO, measurements are useful in guidance, i.e. don't buy a 2W SET amp if your going to use 85dB efficient speakers, but the only thing that really matters is how the equipment meets your individual requirements to connect with the musicians."

Right on!

I think that the topic of record slippage is red herring. I am not aware of any evidence (listening or otherwise) that slippage is happening. However, there is plenty of listening evidence that some phenomenon is at play that fits the concept of stylus drag audibly influencing speed stability. This evidence shows up with or without clamping.

Jj2468, I'll echo what you said about measurements. It is too complex and we don't know what to measure. Both of those statements are often true, that is why you hear them repeated so often. Some things can be measured and some cannot (at least not yet). Some measurements are useful and correlate to good sound and some do not. To the point there is something going on in the world of analog that mimics (or is) stylus drag. It can be heard but nobody to date has been able to measure it, nor have I heard of a credible technique put forth to measure it.

Actually we do have some superb, highly sensitive instruments to measure with, our ears. Too bad many tend to trust them so little.

Jfretch,

And it's not just in the piano, listening to Phil Woods right now and this trumpet has bight, power, delicacy that I just didn't have before on my SME 20/2.

Since Phil Woods plays sax, there must be something really wrong with your table. ;)
Sorry, couldn't resist.

Here's an objective test that might be done.

If one were inclined and had the knowledge and time, one should be able to take a high res digital file created from various turntables as a source and then use computer algorithms to match the signal produced there to an all digital reference master of the same material to discern the differences. Then the question would become what accounts for the differences that would surely be observed.

This would be a fun project. Maybe someday after I retire and need something to keep me busy in addition to current hobbies, including just listening to and enjoying music.

Any EE students out there looking for a masters thesis perhaps?

You want to measure stylus drag ? No problem and very easy to perform at home with little more than 5 cent material and 15 minutes time.
BTW, my comment: "stylus drag - while still kind of a nebulous issue - is best addressed by securely clamping" - contains the (obvious....) technical statement that the record should be (if possible...) part of the moving system (the platter... to benefit from energy transmission and a few other aspects) and that stylus drag as such is indeed "still kind of a nebulous issue".
Which it is as it is depending on several periphery parameters.

Anyway - the test (which result will depend on a handful of individual parameters others may list according to their respective set-up...):

Do make a small mark at the outer rim of a record (mechanical scratch, cut of small color mark - whatever - but make it very tiny).
Do make a corresponding mark at the upper outer rim of your platter so that both marks do blend.
Now go and test.
Give it a full length LP side and see what is the result.
The results will differ considerably depending on weight of LP, slippage on surface of platter, dimensions of stylus, VTF, speed and 4-5 other technical aspects in the dynamic process.
Enjoy.
I performed this test 19 years ago in length and detail and decided to simply eliminate the possibility of stylus drag and lived ever happily after.

Dear friends: IMHO we can't " live " with out measures, more on this latter on.

+++++ but the only thing that really matters is how the equipment meets your individual requirements to connect with the musicians. " +++++

" individual requirements ", this subject is the one that makes the difference and the one that makes everything extremely complex an almost impossible to have " measures " that can predict why something can/could like me or not.

I can't argue why you like something that I don't but I can argue if what you like is more or less accurate or not.

The Universe and the " Mother Nature " works with accuracy in all " orders " , with out accuracy things can end on " caos " and disaster.

In audio things are not different accuracy and accuracy levels are essential: a TT must spin at 33.333rpm not at 34.06rpm, the electrical voltage in USA has to be 117v ( or whatever. ) not 220v , a RIAA eq measurement must be accurate and measure in the 20hz to 20Khz range not between 10hz and 12Khz, etc, etc.

Measure accurate measures help to the audio item designer to know and meet his design targets, he needs to measure and try to design with accuracy on: frequency response, noise level, harmonic distortion, etc, etc,
Today it is extremely rare that an inaccurate audio item can sounds great, of course that due to our each one " individual requeriments " could sounds great but this is not the overall subject.

Me like all of you likes " good sound " / " emotional sound " but I like more ( an always looking at. ) accurate " good/emotional sound ".

There are a lot of good electronics that " sounds good " but are or have serious inaccuracies: amplifiers with high output impedance ( say over 0.5 ohms. ), amplifiers with differences on its frequency response and output voltage on both channels, same with line stages, phono stages with RIAA eq deviation over 0.1db ( designers of phono stages with RIAA deviation on the 0.5db that not only does not cares about but that are proud of that spec!!!!), snesible differences between channels in frequency response and RIAA eq deviation in phono stages, etc, etc, etc. I say inaccuracies that put severe colorations to the sound we are hearing.

I'm very sensitive to inaccuracies/colorations and I'm training/trained to detect very fast and do not tolerate when I can do something about. Some of you know that this " tool " is true because I was at your places and speak on system " colorations ".

Because I like accuracy and neutrality do you think that I don't like " good/emotional sound " ?, " good/emotional sound " is my prime target along accuracy.

Many of us that have " good/emotional sound " even not know how accurate is that sound and many times we don't care about.

The MUSIC has the magic to move us even through a " walkman " in the subway but this is not the subject either.

For me it is a myth that measures has nothing to do on what we are hearing and I have to add: if you know what you have to measure.

When we were on our self Phonolinepreamp design and before ( way before ) we start to hearing it we use the more digital/computer advanced tools/models to " measure " each single stage on our design from different approaches: noise level, THD, IMD, bandwindth, frequency response, etc, etc. We made it first to have what a " perfect model " predict on performance at each single electronic stage, second for when the first unit was build we can compare real measures looking for differences against that " perfect model ", third to have standard measures if we want to build more than one unit, fourth to guess how beat those measures through design or changes on parts.
We made several scientific tests looking for differences between a signal at the input ( with out any electronic line stage process. ) against that signal at the line stage output.
With out tests, measures and the like we are in hand of " random " ( like many people " likes " to " live ". ), accuracy?: what's that?

I'm the " harder " critic of what I hear/heard in my audio system even harder that what I can be with other people systems. I hate mediocrity but I hate more when the people accept that mediocrity.

Like I say: I like " good emotional sound " but I like more accurate good emotional sound!!!!

Regards and enjoy the music,
Raul.

My travels in DD vs. Belt came to a head twice 1) years back with my first Luxman PD444, 2) three years ago with my minty beauty Goldmund Studio. I was a Walker disciple having penned the first review in TAS and having helped Lloyd with the belt tensioning device. I went on to own this extraordinary table while various belt drives migrated through the system. It was not until I brought in for testing the Luxman 444 that I began to see the whys and hows and benefits of DD drive. For the first time the timing and speed accuracy of my reel tapes was mimicked. After much tweaking with sound boards and AC drives I was to achieve a soundstage with the Luxman that did not sit direct upon the loudspeakers, one that breathed and floated like a belt drive. But what a total trip into madness that was. It took months to get this right. And so I read about Porter and his SP10 and his quest and I sit back and toast him a glass of 85 Cab! What an ordeal. Some could just ring up Payer and punk down the dough and get the finished product but us penny pinching masochists had to have it our way. I remember the MBL distributor brought over a CSN rip of Fremer’s comparing the R’port to the mighty Continuum. I thought the Rockport had the pitch better but a rip is just a rip and so many other variables come into play since the comp was not side by side in timeline. I will say with all this that I was smiling a very broad grin when I first brought home the Goldmund… oh, so much space, like a belt drive but now with pitch stability! A grand achievement! Somewhat of a golden color but so what when so much music density is in the room!

I will say I have a deep curiosity for the big Continuum and if I can cajole Mike into letting me schlep up my Pierre Lurne’ concoction (my best table set up to date) I will find out if I need to lighten the Vanguard account by some huge multi thousand dollar amount.

And Raul… no clamp? You shame the turntable PHDs (laugh out loud). Vacuum clamping? Simply the best with the Luxman PD-555- everything was more real. Though I lost sleep over the suction detriments and had to sell it before I had a nervous breakdown! Really!

My best!

Peter

Dertonarm, An interesting test. I'll have to give it a try. But the test is about record slippage and not stylus drag (at least the way I define stylus drag). I generally prefer clamping. I suspect that this is mainly due to better coupling to the platter but some of the difference may well be due to record slippage. Thanks for the measurement suggestion.

Dear breuninger: +++++ " And Raul… no clamp? You shame the turntable PHDs.... " ++++

I made several/lot of tests with different mats and clamps even with vacuum hold down systems, in any case/combinations I detect advantages and disadvantages then I made/make a own design mat with a propietary blen material and I test too where I find that with this mat design not only reduce/minimum the trade offs on performance but that the overall quality performance was/is better with out clamp. I have to say that I never try a ring platter mechanism.

I wish I can/could have our mat design with an integrated vacuum mechanism, this could be great!!!

I repeat again again and again ( many times everywhere ) that the mat/platter build material where the record/LP seats directly is almost the more important subject/factor to achieve the highest quality performance, no single doubt about.

Till today in my knowledge the TT designers and DIYS don't find yet the right build material or blend materials that IMHO is responsable of the recording/play back quality performance ( everything the same. ).

We can see in this thread and other ones where everyone is " worried " about TT drive system, heavy/ light mass, plinth, suspension, etc, etc but no one of these people address the importance ( critical ) of that intimate relationship between that mat/platter and the LP, well maybe I can't explain good: I know that one way or the other these people address that TT " characteristic " but they don't find yet the right one.
IMHO here is where the TT ( as an audio item. ) could give a very high jump on overall quality performance that no one of you could even imagine!!!

If I was in the TT design this single target will be the one where I put all my " energy " because all the other factors/characteristics/targets in TT's are almost know, " invented " and achieved. Btw, the same on tonearms and cartridges.

If we think/make the same normally we achieve/obtain ( more or less ) the same results. We need to " change " if we want to grow-up.

Regards and enjoy the music,
Raul.

Regards ad enjoy the music,
Raul.

And yes to Raul,
+++I repeat again again and again ( many times everywhere ) that the mat/platter build material where the record/LP seats directly is almost the more important subject/factor to achieve the highest quality performance+++

I have to fully agree to this basic tenant. As Yoda would say “most important is the platter to the record interface.”

I would be more on firm ground in this thread to think of the differences in terms of _difference of coloration_.

Pure lead or a high lead mix: sound has a dead "it-ends-here" coloration. very accurate reproduction of the space between the images and notes.

Hard rubber like formulas: detail and depth to the coloration, a color not unlike putty or clay, very nice space between the notes but flavored with something extra.

Clear Acrylic: more of an endless feeling to the coloration, almost a reverb of select frequencies are accentuated. Have to get used to.

Special formulas (Goldmund, Lurne' and other Alchemist designers): a small shadow coloration that follows the music, like SETs somewhat. Very addictive to my ears at this time in my career. Huge space and you can minimize a touch of gold glow if you roll up your sleeves and try creative belts, AC/DC drives, and outboard motors.

Peter

This is a most interesting post and I thank all the knowledgeable Goners for their contributions. As Raul stated, sharing knowledge is important. And 75 comments in just one week clearly shows the level of interest in this topic.

BUT, if I understand this point correctly, I have an issue with one suggestion made a few times here. That is the idea that it is necessary to test different drive systems with "all else being equal". Really? Since I believe many contributors here are in fact knowledgeable audio folks, you may agree that component compatibility is very important in this hobby. If so, why would we assume that the same cartridge, arm, plinth, suspension, support, etc. systems would be "ideal" with different drive systems?

My contention is that the only way to compare different drive systems would be to do so with each one "optimized" for best performance and therefore not compromised. Of course then we have the problem of optimized by whose standard or taste?

So just like there being no one speaker that works best in every room, or with every amp, I guess it is up to each of us to find which drive system, in combination with our other vinyl playback components, brings us the most satisfaction. Pax.

Pryso, It depends on what you are trying to accomplish. If you want to get an accurate understanding of the sonic affect of a particular component then you want everything else to remain constant. In this case it's about gaining understanding and not necessarily optimizing for the best sound. With understanding of the contribution of various components in isolation then you are in a much better position to then optimize.

It is certainly possible to make meaningful judgments without everything else being equal but it is much more difficult and more error prone.

There is usually some synergy between components, but I believe that as the level of quality goes up this becomes less important. I think that a motor implementation that requires a particular tonearm or cartridge to sound optimal should be considered to be flawed. A quality, neutral implementation of any component should work very well with any other quality component. Of course in the real world this all too often is not the case. But it should be a goal of good design.

Changing drive alone would be a purely academic exercise, except for perhaps for those that might be willing to custom build their own table.

Practically, it is the overall design and integration (table, arm, cart, phono pre-amp) that matters for most. Any type of drive mechanism, if done well, will work just fine.

The experiment has been done by anyone who converted his Teres or VPI turntable from belt- to rim-drive using the motors now available from the respective manufacturers. In these instances, all other factors are held constant; only the drive system is changed. As far as I know, almost all end-users have preferred rim drive vs belt drive. One could be skeptical of those claims, because there is a lot of subconscious bias in favor of hearing an improvement, in my opinion, when one spends money for such "upgrades". (The very use of that term suggests a bias.) But I am inclined to believe that the benefits are real, based on my own completely uncontrolled experiments comparing a "good" belt drive table to various idler-and direct-drive ones. (I am a scientist by profession, so this stuff bothers me.)

I don't understand the aversion to measurements. If you don't like measurements, you don't have to do them or pay attention to them.

If measurements don't correlate with perceived improvements in sonics, then the measuring tool needs improvement. The poor correlation of THD and perceived sonics is a good example.

Audiophiles have differing tastes. The assumption that measurements cannot accomodate differing tastes is probably untrue. In fact, if an audiophile was able to correlate measurements with his or her sonic preferences, it would likely improve the his or her ability to predict whether a particular purchase will be satisfying. Just a hypothesis.

Regarding belt drive slippage. Let's assume for the moment that a) the stylus places meaningful drag on the platter, and b) such drag varies in intensity with the shape of the grooves of a record, and c) the variation in intensity affects rotational speed to a degree that it creates an objectional variation in pitch. It would seem, to me, that compensating for the problem by "belt slippage" is akin to a servo motor that always reacts after the fact. So, to compensate for the inaccuracy of the servo motor (belt slippage) you use a very heavy platter so that the affect of the stylus drag upon the rotational speed of the platter drops below an objectionable degree of variation in pitch. I understand the hypothesis that the mass of the platter minimizes pitch variation.

I don't understand the hypothesis that belt slippage does something to minimize pitch variation. a) Why? b) How would you control belt slippage so that it acts predictably and with repeatable results?

In regards to testing drive systems, here are a couple of ideas. Test 1. Place very tiny hash marks next to a groove of a record. Play it and film it with a high speed camera or strobe (using a macro lense or microscope). Measure the speed of the stylus against the hash marks. Switch turntables and repeat. Compare the speed of the stylus over the same section of grooves. Test 2. Take a teres turntable. Play a short, dynamic, section of a record. Record the output from the loudspeakers using a microphone and input it into a computer. Do it for the belt drive version and the rim drive and use the same record grooves for each. Load the sampling into a computer software program that charts frequency and transients over time. Compare the durations and frequencies of the samplings by graphing one sample over the other where the x axis is time and the y axis is frequency.

Jeff

Lew, you offer a great example of comparison and I should have remembered it. A friend of mine owned a VPI Scout and became curious about the current rim drives. Although it cost about the same as his table and arm, he ordered the VERUS rim drive/controller system. There has been full agreement by everyone who has heard it that this rim drive plays more realistic and satisfying music. Interestingly he took this system to his VPI dealer where they compared the original belt drive to the VPI rim drive to the VERUS. Each of the three produced a different sound.

So I guess there are limited opportunities to compare different drive systems. But I still feel in most cases one could not make a fair comparison as to which system is "best" or "most musically satisfying" when the set up for each system is not optimized for the best results with each individual drive system.

J2468, No aversion to measurements here. It's just that I tend to put more trust in our ears.

I find the propensity to associate stylus drag with slippage curious. Although there will always be some amount of slippage with any friction drive (Mark Kelly calls it scrubbing) I do not think that it has much if anything to do with stylus drag.

I believe that an important issue in drive design is delay of torque delivery from the motor. This is akin to what you posted about servo reacting after the fact. A motor connected to a platter via a compliant belt is unable to apply torque to correct short duration speed fluctuations. If the platter decelerates slightly the motor applies more torque to compensate. But the belt simply stretches a little more. The energy ends up being stored in the belt causing a delay before it affects the platter speed. So the correction ends up arriving at the wrong time often making matters worse.

A heavy platter changes but does not solve the problem.
A massive platter will reduce the magnitude of a short term variation but extends it over a longer period of time. A light platter will conversely allow a larger speed variation but it recovers more rapidly. Heavy and light platters sound different but neither solve the problem.

I like your idea of using high speed photography to measure speed variations from stylus drag. But perhaps there is a better way. Rather than use a camera a reference track with a precise, constant tone could be used. This would require two tonearms and a test record with a steady tone and a track with variable modulation. The two tonearm part is easy but I am not sure if a suitable test record could be found.

It is expected that the magnitude of speed variation from stylus drag would be extremely small. To detect and measure the variation would require high precision. It may well be that audible speed variations would be too small to detect with a setup that is not prohibitively expensive. But thanks for the idea. I am interested in pursuing it.

Teres, thank you for a very articulate explanation.

I agree that our ears and our perception are more important than a number on paper. I do believe that with study, we will learn to improve our correlation between measurements and sonic satisfaction. If a measurement does not correlate with perceived sonic satisfaction, then the measuring system needs improvement and such theory does not bar individualism.

In other words, if a measurement not help then throw it out.

Dear Jj2468: +++++ " No aversion to measurements here. It's just that I tend to put more trust in our ears. " +++++

+++++ " I agree that our ears and our perception are more important than a number on paper. " +++++

well, yes and no: in an strict point of view where the target is to achieve a performance with the less " colorations " ( where colorations means: noise, distortions, inaccuracies, etc, etc. ) those two statements are untrue.

I know several audio system owners that are really proud of each one audio system quality performance where they have severe " colorations " because they have an unmatched speaker electrical impedance curve with an amplifier(s) with high output impedance or whatever other " problems " around. That they like it does not means the performance is right because that performance is " wrong ". First step to be confidence with our ears is that we have an in deep experiece/knowledge about music and how it sound or shoul be to sounds, what we like has nothing to see with what is the real thing if we like the " wrong " music presentation.

Problem with measurements is that not many people " understand " it. Many measurements say almost nothing alone and only make sense when we " combine " two or more measurements.
The match between amplifier/speaker impedance as a RIAA eq. deviation are only a few of the measurements examples that alone can tell us part of what we are hearing, normally we have to combine several measurements to more or less understand what's happening.

IMHO today ( in these times. )it is pathetic to read elsewhere that what it counts is only what we hear, it does not matters that what we hear is wrong way wrong!!!!!.
This kind of thinking has a price very high price that all of us ( the high end audio world. ) are paying: mediocrity, that's what we overall have in our home audio systems. This is a fact not an opinion: take a look to almost all the audio links in the audio chain and we can find that in the last 20-30 yyears we don't have almost no improvements or signs that the industry is growing-up in quality performance. We are extremely proud and happy because our SP-10s are wonderful or because the vintage MM/MIs are great alternative, my God!!!!!!!

Shame of us and shame of industry we have ( with exceptions. ).

Regards and enjoy the music,
Raul.

I agree on the post as a whole Raul.
However - "wrong" or "right" will - in the very end - always be up to the individual listeners taste.
There is no absolute here (which is were...) - not in hearing.
Hearing is always a lone and individual one,- and so will be the final judgement about a certain sound systems performance: - individual.
I guess it is indeed rather a matter of different levels of experience.
The seasoned listener to many different systems with a certain technical background will always have a wider foundation - a more solid ground - on which he can make a "judgement".

Dear dertonarm: Agree, so many of us has a lot to learn on the whole subject and try to go up faster in each of us: audio learning curve.

regards and enjoy the music,
Raul.

Raul, I don't think that the measurement vs listening argument is about accuracy vs tastes. Take for an example an early 70's solid state amplifier. Those amps were made in the height of meter watching. They excel at the measurements that you frequently cite, flat response, low distortion, low output impedance. In spite of exemplary measurements they sound terrible and more to the point they sound nothing like the original performance. So good measurements does not necessarily equal accuracy.

You are correct that the target is to reduce colorations. But colorations (or lack of) cannot be defined by a simple set of measurements, in particular the three you just cited. Otherwise those 70s amps would sound both fantastic and accurate.

Measurements are useful but if we were to make the measurements more important than hearing we would all be listening that lovely 70s technology... well actually most of us would have lost interest and found some other hobby.

I did not propose that the goal of measurements is accuracy. (Although in the determination of platter stability pertinent to belt drive versus direct drive, accuracy of constant rotational speed probably is the goal). For somebody who likes colorations, measurable inaccuracy may be the goal.

For example, Raul cites an audiophile who likes colorations. Raul appears to dislike artificial colorations. It is not my duty or right to tell somebody what they should like. It is conceivable that measurements, graphs and other repeatable and predictive forms of communication could help each of these two audiophiles get what they want.

So, I believe that if a consumer wants pitch stability that is suitable to his personal demands, reliable measurements that describe the differences between the platter rotation of belt drive versus direct drive would help the consumer (and not help turntable manufacturers who don't want to learn and improve).

Dear Teres: I agree on that 70's electronics example.

I want to argue not what happen in the 70's with electronic designs but what we have today. It is clear even today that there are audio items that could measures good but sounds awful because different factors: bad design, bad parts selection, bad execution design, wrong layout, bad quality circuit board material, use of negative feedback in the wrong place or exesive one, use of op-amps or IC chips that for lower distortions use hundreds of negative feedback, etc, etc; but with a decent design and good execution design with the right parts selection and the like something that measures good normally sounds good too.

The understand of mesures and its correlation with what we are hearing is difficult because ( example ) we can have an audio item with very low distortion figures and could sound bad because the distortion measures alone don't tell me the full " history ", we need to know which kind of distortions are generated on that audio item: even/odd harmonics and at what output level, many items has problems because inadequate phase frequency response and many other " ocult " factors that the manufacturer normally not disclose and only through specific measures we can know the why's/where what we are hearing.

Sure that could be that an amplifier with low output impedance ( say: 0.05 ohms. ) can/could sound bad and many examples like this tell us that our first step is that we have to understand what each single measure means, second step we have toknow what to measure, where to measure and how to measure and third ( not last step, there are more. ) how some of those measures are related to give us an answer of what we are hearing. I know is not an easy task but IMHO we all need to start an overall understanding about, this understanding IMHO could help to each one of us to improve the quality performance of what we have at home.

Teres, I'm for accurate good emotional sound: nothing less. If our ears are true trained on music we can discern between a good sound ( colored one ) and a good accurate sound, which one do you prefer?, certainly an accurate one if you are trained to discern it. Problem is that this is more easy to say that to achieve because to have this very high grade of discern require wide experience not only on music but on understanding of the different audio link performance in an audio chain, this means a wide experiences hearing a lot of different audio systems in different environments, in a few words: be an expert! with all what this word means.

Regards and enjoy the music,
Raul.

Raul your comments above 1-8-10 ending with Shame of us and Shame of industry we have ( with exceptions )

The burden of blame for promoted WAY over priced mediocre junk rests with the typical consumer involved in this hobby.

Of course slick marketing and promotion through the audio media helped steer this hobby where it is today.... They know the typical customer and know them well.

Just being a designer of any said component or reviewer certainly means nothing if you can't hear in the first place. However with the right distributor and other industry types your product will sell even at an highly inflated price....

Most certainly! there are exceptions to this.

I have two 30+ years old turntables, which are Luxman PD-444 using direct drive. These have co-existed over the years with Linn LP12, Pink Triangle, multiple VPIs, Mission, Rega, Systemdeck, Thorens, Lenco, Transcriptors, Michell, Sota, Kenwood, Pioneer and other turntables and have survived every challenge. There was a Luxman PD-441 little brother in the mix too -- excellent but not quite as lovely as the larger, heavier PD-444 that accommodates two tonearms.

Listen to a Luxman PD-4XX turntable and you will not doubt the ability of well-enegineered direct drive to deliver music with energy, flow and tone, against quiet backgrounds and audible speed stability.

These specific Luxmans also represented sound thinking with persistent validity. I recently disassembled and reassembled one of my PD-444s and was struck by how much it shares with the current rave, the belt drive VPI Classic. The VPI Classic has a solid plinth of MDF bonded to steel and compressed with through-bolts. The Luxman has a core of lower-density chipboard sandwiched tightly sandwiched between heavy iron plates with an aluminum overlay on top, and the whole sandwich is compressed via through-bolts. The VPI Classic has its belt-drive motor mounted directly to the plinth, which also holds the main bearing and tonearm. The Luxman's direct-drive motor is also mounted directly to the plinth incorporating its (mag-lev load reduced) main bearing and tonearm mount. The VPI has an actual weight around 55 lbs. The Luxman 444 weighs about the same.

But one difference aside from dd vs. belt drive is that the Luxman stands on very good (but dated) tuned-resiliance feet with spring, rubber and silicone elastic/damping elements. The VPI is mounted on solid feet of Delrin and metal. So I recently updated my Luxmans to solid footing. Living now in a slab-foundation house with wood-over-ply-over concrete floors, I have no concern with footfalls. So I removed the sprung feet from the Luxman and replaced them with heavy (nearly 1 lb. each, like Classic's feet) BBC brass cones attached to the PD-444 base by double-adhesive Herbie's Grungebuster dots, and the down-pointing cones sit in receiving cups that in turn fit perfectly on top of Aurios Classic media bearings.

Result? Vinyl sound that is firmly planted, digs deep, is loaded with tone, dynamically vivid, spatially generous as appropriate to the recording, and alive with realistic transient clarity. I will keep this sound over any belt-drive turntable I've owned. I do believe it can be exceeded in some significant ways for much more money by a contemporary belt or thread-drive design, but then too there's the ~$8,000 Brinkmann Oasis to consider. It is considerabily more difficult for an entrepreneurial company, usually undercapitalized or bootstrapped, to design and bring to market a well-executed direct drive turntable. What would a Luxman PD-444 that cost $795 in 1978 cost if developed and introduced today? In hifi economics it would be squarely in the realm of high end.

Phil

Inflation calculator link>>[http://www.dollartimes.com/calculators/inflation.htm]

I don't think an inflation calculator answers the question of what a Luxman PD444 would cost today. Circa 1974 when that turntable was designed, a substantial manufacturing infrastructure and technical coterie existed in Japan for making direct drive turntables. And the market was larger, supporting higher volumes and better marketing efficiency. Those assets are sharply truncated now. For a new company to research, design and manufacture a similar product in low volumes would, I expect, require a selling price well above what inflation suggests. By inflation alone, a PD444 available for $795 in 1978 should come to market for just under $3,000 today. The VPI Classic at $2500 with tonearm gives some hope that might be a supportable assumption. The fact that a simple Pro-ject Xtension (belt drive but mag-lev load-reduced platter and solid plinth) costs over $5,000 without arm and with a commodity motor, or that a Brinkmann Oasis DD costs over $8,000 without tonearm, suggest an inflation-calculated cost won't cover it, given tiny market volume, contemporary manufacturing costs, and modern channel inefficiency in high-end audio.

Phil

Phil, I agree that the inflation calculator does not answer the question. The channel inefficiency part is key. Another point was that in 1978, the USD/JPY rate was much higher than it was today (the dollar was at twice as strong vs the yen, and for a decent part of the year was 2.5x stronger). Indeed the USD was much stronger against a host of currencies. Most of such a table would be manufactured outside the US I imagine and would therefore have those local manfacturing/profit margins built into non-USD currencies before being brought here to have another multiple (or two) taken on the sale.

Owned both tables and sold them. The Denon 47 F was nosey a lot of record surface noise. Upgraded to the Aries 1 that I enjoyed for many years. But after purchasing a TTW Audio TT I realized the Aries was colored and soft sounding.

Cjaronica, This is not to dispute your logic in ending up with a TTW turntable, but a turntable per se is not going to exaggerate "record surface noise". That phenomenon is typically due to the phono stage, the cartridge/tonearm combination, cartridge set-up, or a combination of all these elements.