Let's say it has a minor impact on the belt, whatever it is, and that counts for a lot.
American Sound, "The Absolute Nothing"
- Thread starter PeterA
- Start date
Thank you. But this still sounds more like theory than practice.
What is the practical sonic benefit when playing a record provided by a turntable whose platter spins freely for a long time after power is removed?
If it has less impact on the belt, it means that it has less w&f from that point of view.
Thank you.
1) Isn't more relevant to sound quality what is a turntable's wow and flutter when under power?
2) Let's say one turntable's platter spins freely for three minutes and another turntable's platter spins freely for 30 minutes. Is the presumed difference in wow and flutter between these two turntables audible when playing a record?
3) Why do you assume there is a correlation between a very long free spinning platter and sound quality?
4) If you think a very long free spinning platter after power is removed is an important contributor to resulting sound quality, why do you think we don't hear about turntable designers explicitly designing for this feature or bragging about it in their marketing literature?
(I really intended these questions for Peter because he writes about this feature of the AS-2000.)
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1.of course
2.very likely
3.The first answer I gave to PeterA was, that it is more important for the quality of the turntables how long the last turn lasts.
How long the platter stops is an indicator of how precisely and to what tight tolerances the turntable is made. In my humble opinion, this counts more than the weight of the turntable or platter.
It is hardly a parlor trick, Ron. It is a direct indication of rotating platter inertia. It contributes to speed stability which is audible in the sense of ease and calm in the presentation and in the level of realism in the recorded instruments’ timbre.
There are many factors involved in good sound. Stable speed and the degree to which a motor’s influence on the platter is audible depends on many design choices. Low friction, high mass is one approach. Based on the turntables that I have directly compared, shorter free spin times indicate higher bearing friction. That creates more noise that must be dealt with. There are also implications for the motor controller and how it manages the motor that has to deal with a platter that spins less freely. I hear the differences, but the designer has a better understanding of exactly what causes what and affects the sound.
For more details, you might enjoy interviewing some turntable designers. It’s quite fascinating how different turntables can sound.
Dear @Ron Resnick and @hb22,
Apologies for jumping into your discussion. I realize your question wasn’t directed at me, but I wanted to address something regarding the long spin-down time of a platter after the motor connection is terminated (e.g., the string is cut or the belt is removed). A long spin-down time simply indicates the presence of a high-mass platter and/or low-viscosity bearing oil, but it does not improve wow and flutter (w&f) performance. In fact, it can worsen w&f because the oil inside the bearing has an important secondary function beyond lubrication: braking.
Braking is the final step in reducing w&f, complementing other design elements like motor decoupling, physical separation of the motor, and the use of a high-mass platter. Motors do not run at a perfectly steady speed—they constantly slow down and speed up to maintain an average speed. This happens within milliseconds, but it’s still audible. Low-friction braking reduces the motor’s negative effects on the platter by mitigating these speed fluctuations. If you have a high mass platter you may think it’s impossible for motor to take control of the platter but after a speed up period a platter needs only a small amount of force to keep going, even the high mass platters. That’s why motor can easily transfer negative effects to the platter.
All the design elements I mentioned aim to address this issue because, without them, the motor effectively “takes control” of the platter, transferring the unwanted effects of its control pulses. A consistent load on the motor helps to prevent this and reduces its negative impact. Proper braking ensures this consistent load, which is why experienced designers always engineer turntable bearings with clearances matched to the viscosity of the chosen bearing oil. In case of the absence of lubrication like air suspended platter there must be other solutions for braking.
If your turntable performs well in terms of W&F and platter spin-down time is long it will surely perform better with better engineering of braking.
Designing a turntable platter that spins for a very long time after the motor connection is terminated only demonstrates a lack of understanding. In my humble opinion statements like “but my turntable is designed that way” or “the designer solved it differently” are irrelevant here—it’s a straightforward principle.
Apologies for jumping into your discussion. I realize your question wasn’t directed at me, but I wanted to address something regarding the long spin-down time of a platter after the motor connection is terminated (e.g., the string is cut or the belt is removed). A long spin-down time simply indicates the presence of a high-mass platter and/or low-viscosity bearing oil, but it does not improve wow and flutter (w&f) performance. In fact, it can worsen w&f because the oil inside the bearing has an important secondary function beyond lubrication: braking.
Braking is the final step in reducing w&f, complementing other design elements like motor decoupling, physical separation of the motor, and the use of a high-mass platter. Motors do not run at a perfectly steady speed—they constantly slow down and speed up to maintain an average speed. This happens within milliseconds, but it’s still audible. Low-friction braking reduces the motor’s negative effects on the platter by mitigating these speed fluctuations. If you have a high mass platter you may think it’s impossible for motor to take control of the platter but after a speed up period a platter needs only a small amount of force to keep going, even the high mass platters. That’s why motor can easily transfer negative effects to the platter.
All the design elements I mentioned aim to address this issue because, without them, the motor effectively “takes control” of the platter, transferring the unwanted effects of its control pulses. A consistent load on the motor helps to prevent this and reduces its negative impact. Proper braking ensures this consistent load, which is why experienced designers always engineer turntable bearings with clearances matched to the viscosity of the chosen bearing oil. In case of the absence of lubrication like air suspended platter there must be other solutions for braking.
If your turntable performs well in terms of W&F and platter spin-down time is long it will surely perform better with better engineering of braking.
Designing a turntable platter that spins for a very long time after the motor connection is terminated only demonstrates a lack of understanding. In my humble opinion statements like “but my turntable is designed that way” or “the designer solved it differently” are irrelevant here—it’s a straightforward principle.
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What you write is true. However, here is a debate about Air Bearings turntables.That's the difference.
Motor doesn’t know if there is air bearing or not and doesn’t care. It continues to reflect it’s negative effects. So, whatever I’ve written applies to all. Direct drives on the other hand are irrecoverable.
BTW my explanations about bearing and w&f are all from a technical standpoint. Which turntable and which topology sounds better is a whole different subject. IMHO sound quality cannot be directly correlated with w&f performance as well as other technical specifications.
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If you care only for what I think Ron, just call me by phone. You post your questions on an open forum so you should expect the readers to respond freely. Why qualify or attempt to control who posts?
You had ordered the AS2000 which is actually the table I made that free spin comment about and the one on the video I made demonstrating this quality. You would know more about it if you owned one, and you could actually compare it to other tables for yourself, as I have. I am not a turntable designer, but I have compared the sound of turntables with different platter masses and bearing frictions. Many design decisions contribute to the overall sound of a turntable. Free spin time is only a measure of specific qualities in some designs.
One of the contributors to sound quality is the degree of influence a motor and its controller have on the platter both in terms of timing and controlling, but also in terms of physical impact through the connection. A massive platter spinning freely with very low bearing friction, or zero contact as in this design, can maintain speed with very little influence from the motor or its controller. This is born out by my experiments with belt type, tension, and length. All effect the motor's influence on the platter and are clearly audible in my system. To my ears, the less influence the motor and controller have on the platter to maintain a constant speed, the more natural the sound.
I did not test the free spin time of this new The Absolute Nothing turntable because I did not have the time during the set up or when visiting the factory. The platter is about twice as massive as the one in the AS2000, so it perhaps spins even longer. I do not know why manufacturers do not discuss this, but I suspect it is because every turntable is designed differently for different reasons, and because results would very dramatically. Manufacturers also do not provide videos of their turntables with a Sutherland Timeline tachometer on them. These American Sound turntables are built to extremes.
This free spin discussion is only for the low bearing friction, massive platter, belt/thread drive approach. As you know, there are many other turntable design approaches with different results and different sounds.
mtemur, I agree that the motor does not know the bearing type, but does it not need to react to the forces presented to it by the connection to the platter? Free spin time provides some indication of the friction on the platter. Then there is the inertia of the platter and the ability a motor has to change the speed of the platter when it is rotating. I think I understand what you describe about the breaking effect and the impact different oils may have. Do you not think that the sheer mass spinning creating high inertia acts like a break to resist the influence of the motor on the platter, especially when the thread is long, thin, and loose?
Does very high inertia not have a breaking effect on the rotation of the platter? I know quite literally from my own "hands on experience" that it is pretty difficult to physically stop my platter from rotating when I turn off my motor.
We agree that we do not want the negative motor effects to reflect into the platter thus affecting the sound. The approach used in these turntables attempts to minimize exactly those negative motor effects.
Thank you, Peter!
I absolutely will ask turntable designers about this in interviews going forward.
There's no doubt it's cool that a turntable platter has so little friction that it can achieve this. We all agree that lower friction is good. We all agree that lower "noise" is good. We all agree that speed stability is good.
I'm curious how these theories relate to what we actually hear. For example, if the AS-2000 platter stopped spinning freely in half the time that it does presently would you actually hear any difference in a sense of ease and calm? Or, for example, once the friction is low enough to spin for three minutes (to make up a number) does the ability to spin freely longer make any difference to what we can actually?
Ron, we do not seem to all agree that low friction is good. Ask mtemur. It may depend on platter mass and other things. Perhaps a lighter platter with more friction works too as a different approach.
The free spin time is one indication of what is required from the motor to maintain a constant speed. How the motor does this can affect what we hear. Degrees are a matter of debate. The American Sound tables take this to an extreme, and it is only one aspect of the sound character.
I know experiments have been made with the air pressure supporting these massive platters. The pressure affects friction and I assume the free spin times. Different pressures are audible according to DDK who has listened and tested and heard all of this in his revealing system. How much that matters to others I do not know.
You should experiment with your Brinkman belt, the type, the tension, and the length. Perhaps you will hear differences. Shorter free spin times will limit how much experimentation you can do with belt tension, because the motor and its connection to the platter must ultimately be able to maintain proper speed. Theory is great and should be understood during the design phase, but listening is also a good way to understand what is happening.
Thank you, but it's just not the kind of thing I'm interested in or that I have the patience for. I'm happy to go with whatever the designer of the Brinkmann turntable provides and recommends, and leave it at that.
I agree!
I get that. You like theories. You should ask your designer the questions then. Happy to go with it is fine too. I discussed much of this with DDK, but my real learning and improvements came from doing my own experiments.
I've been reading the topic from the beginning and this made me laugh. You were probably joking when you wrote this?
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