I think the best course of action is to buy a turntable on the basis of the quality of sound it produces versus its cost to purchase, and to forget belt versus direct versus idler.
If you want to buy a sports car do you buy on the basis of the engine configuration (V8 versus turbo versus supercharged, versus rotary) or do you take the cars for a drive ? |
"constant drive of the platter "
The platter is still driven by a motor, and that motor is still subject to noise or vibration. One could argue that a belt filters motor noise.
Why would a lighter platter directly driven by a higher torque motor produce a more constant rotation with less noise than a massive platter driven with high inertia by a low torque motor ?
To me it is not obvious that direct drive has any advantage over belt drive. |
"This means it takes torque, an active force, a bigger motor, to combat stylus force drag, that simple mass is quite simply insufficient."
How does the stylus know the difference between a high torque motor and a large mass with a large polar moment of inertia ? I cannot understand how a large polar moment of inertia is any less capable of overcoming stylus drag than a high torque motor.
Do you feel a difference between being run down by a car (being actively driven by a motor) or a large rock rolling down a hill ? I would say that both will crush you equally, one using its motor, the other a very large inertia. |
"I would surmise that the boulder would be slowed somewhat by your body since it was coasting whereas the car which is actively powered could be completely unaffected by your presence in its path."
I think you'll find both are slowed. Cars are slowed by headwinds, even though they are powered. A car is slowed when it hits a tree, even when it's powered. A large rock rolling down a hill can smash to splinters a tree that would stop a car dead in its tracks. Even if the incline is very slight, such that the gravitational force acting to roll the rock is very small the rock carries a lot of energy in its inertia.
All I'm saying is that I cannot see any way in which high torque/low inertia is inherently superior to high inertia/low torque, for purposes of speed stsbility. |
Bob ... actually you and I are in agreement. The torque is either in the high mass platter, or in the motor, or it is in both. Where it is doesn't matter, what matters is that there is plenty of it.
I'd even go further and say that, I would expect the theory to favor a belt driven table of very high mass, and with a very low torque motor, since a revolving high mass not only has plenty of torque, but because of the low torque motor it should also have a very high degree of speed stability, and noise rejection. The difficulty in the high torque motor approach is guaranteeing that the high torque motor is low noise, and has an extremely stable rotational speed.
But I'd still like to hear a Lenco, Garrard and SP10, and I'd be happy to buy whatever sounded best to me, regardless of my theoretical preconceptions.
My experience has been that solo piano is the torture test for turntable speed stability, so a dose of Beethoven piano sonatas should be all that's required to find the best turntable. |
John
"The torque, as in stored energy/moment of inertia, is not sufficient to combat stylus force drag, it takes an active motor force to push the platter through the dramatically-cut grooves and the variable stylus force drag they cause: it will still slow, the belt stretch, and then contract, albeit more slowly as it has to drag so much mass, and the motors used in belt-drives are insufficient to push the LP through and keep the speed rock-steady. "
Now re-read Rushton's post. If stylus drag is really capable of slowing an 80lb platter how could the walker continue to play with the belt cut for tens of seconds ?
Can people not see the equivalence of torque by stored inertia and torque by electrical energy (motor) ?
Again, I'm perfectly open minded when it comes to purchasing, but those who decry belt drive must first give some reasoned argument as to how a low torque, massive platter design is supposed to be slowed by a minute diamond dragging through a groove with a tracking weight of only a few gramms. |
"You can't grind steak into hamburger and then make steak again no matter how constant the speed of the grinder or the ungrinder."
Actually (in theory) you can. A sampled waveform, sampled at a frequency of at least twice that of the highest frequency in the waveform, that is reconstructed with a sin(x)/x filter will perfectly reconstruct its original signal. Once again theory says that digital can produce perfect sound. The problems are in the implementation. |
Is there a paper anywhere that has measured the effects of stylus drag on a turntable with a massive platter ? It seems almost infeasible that a 2gram tracking stylus would have any perceptible effect on 10+lbs of spinning platter. |
"For that question to be meaningful one would also have to know what the threshold of perception is for this phenomena. Measuring something is often easy. Correlating that measurement to perceived differences is often fraught with difficulty."
True, and not true. It is still a valid question, because I hear many people refer to stylus drag, but nobody offering proof that is it
a) Occuring measurably
b) Occuring at a level that we might expect the ear to be able to resolve.
Digital jitter has been accurately measured, and then somewhat correlated with audible effects. It's not too unreasonable to expect turntable manufacturers to do the same ? |
I would add, at what point does the stylus drag and micro speed variations in a high end turntable fall below the speed stability of
a) The cutting lathe
b) The master tape recorder
c) The 2" multi-track tape source
so that the turntable is now more accurate than the LP it is playing ?
I must admit Chris's post comparing analog speed variation to timing jitter in digital is quite thought provoking ... I'd never thought of them in the same way, but in retrospect it's obvious that they cause similar distortions to the waveform. |
John, I have not personally argued that belt drive is superior. I would truly love to hear a 3 way shootout between a Lenco, an SP-10, and a Teres, Galibier or similar belt drive. I haven't the time, the will or the money to do so.
I have read posts from many who say the Lenco is the best. I have also read posts from people who have heard Lorricraft Garrards and like the bass, but find them lacking in subtlety and detail in comparison to a Nottingham Hyperspace.
I fully agree that your ears are what matters. You should buy what sounds best to you. What I DO NOT agree with is that you are able to declare the Lenco the best turntable, because you and some others like the sound the best. Does this prove that it has the best speed stability ? Not at all, it proves that you like the sound best.
My experience is that the torture test for speed stability is solo piano, preferably a slow movement, like a Beethoven sonata. Yet whenever people describe the strengths of the Lenco or Garrard the first word is always BASS. That does not correlate with my personal experience where a turntable can produce articulate and deep bass, but have terrible speed stability when it is introduced to solo piano.
So, in summary, there may not be a one-size-fits all best in terms of what sounds the best, because we all have different interpretations. There may be a best in terms of measured performance, but using your ears might not be a good way to come to a conclusion. |
Jack .. there's a Technics SL-1000 (consumer version) and a couple of SP10 Mk2s on ebay right now, for between $400 (no plinth) to $800 (plinth and arm).
I vote you buy one and report back to us in a month or so :-) |
"Speed-stability is the crucial issue, not speed-accuracy within reasonable limits."
Zaikes ... I agree with you. If speed accuracy were more important the CD vs LP debate would have died long ago.
Speed stability is what really counts.
Regarding the limit of discrimination this reference has it at 0.5%
http://www.indiana.edu/~emusic/acoustics/pitch.htm
So you could argue that the difference between 0.001% and 0.01% is academic. I would even argue that the orchestral players are not able to tune their instruments to better than 0.1% so you are fooling yourself if you think a turntable needs to be substantially more accurate.
Since speed stability problems cause direct distortion to the waveform they are much more noticeable.
Doug ... how does an absolute speed error break harmonic relationships ? If we are 1% fast then a lower A is 444 Hz (instead of 440Hz) and an upper A is 888Hz instead of 880Hz. The doubling of frequency per octet relationship is still maintained, just shifted slightly 1% up in frequency. |
Raul,
I'm in general agreement that measured numbers determine the accuracy, but I will take issue on one small nit-picky area.
Lumping of wow and flutter is misleading, because I suspect that the frequency distribution of the wow and flutter noise will have a very pronounced effect on the perception of sound quality, just as it does with digital jitter.
I could have a table that had lousy wow measurement at 0.5Hz, but I suspect it would be much more pleasant to listen to than a better measured table with wow around 2kHz, right in the midband.
I truly believe in measurements and a scientific approach to audio, but often the most difficult thing is knowing exactly what to measure.
This has been a really fascinating debate, by the way, and I hope one day I'll have the time and/or the money to try a few more of the tables out there. |
"Like the turntable itself, this topic goes round and round."
Did you buy an SP-10 or a Lenco yet ? If not why not ? :-) |
