Is Direct Drive Really Better?

The universality of torque aside, Walker's cut-belt demonstration was a bit of circus stunt. Of course the pitch and tempo of the record dropped during the 20 seconds -- that's a fact of nature -- it just did so slowly and not very much, so nobody noticed through their surprise. If they didn't notice that, then they didn't notice whatever effects of dynamic stylus drag were superimposed on that -- not only because of shock and awe, but because there was no reason for those effects to have changed much before and after the cutting of the belt. The massively heavy platter minimized those effects before the belt was cut, not the motor, and removing power didn't change that. Whatever dynamic speed modulation by the stylus sounds like, it couldn't be a gross effect, it probably manifests as a subtle alteration of textures or something, maybe a bit of clouding of the soundstage, who knows. Hell, there are ways in which you could predict *any* turntable would sound *better* without its motor interfering, if only they all could keep spinning away like the Walker. (Maybe cutting the damn belt even granted it some of the virtues of direct-drive for a time ;^) Point is, there was never any question that an 80lb. platter on an air bearing for $20K+ could help overcome dynamic stylus drag, the real question is if that's the only way, or even the best way. (I've always assumed the really massive platter jobs must have very low flutter but rather high albeit long-period wow, and maybe that's a smart tradeoff.) Or if any of that matters to the sound nearly as much as the resonant characteristics of the turntable -- if not, then use any drive method, just make sure the thing has good vibrations.

"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.

I know much less about the science and engineering of this subject than most of the excellent posters in this thread, but I feel the point I made above merits further exploration. Tom (Macrojack), your response, which is essentially that problems with the CD format obscure the big payoff it delivers in speed stability, is certainly credible, but I'm not willing to let it go at that.

What are the sonic benefits people ascribe to DD and IW? Better PRaT? What else? If this were due to better speed stability alone, surely we would hear at least some of this benefit from CDs. Do we? As piano is the reference standard for hearing pitch stability, shouldn't this be obvious from CD? (Some people think it is, but not all of us.)

My layman's hypothesis is that average speed variation from the reference (33 1/3) is more significant to sonics (and more widespread) than the very tiny moment-to-moment stability issues that are being argued about in this discussion. Rega tables run fast and -- guess what? -- they have great PRaT.

And let me toss out another idea. How stable, moment-to-moment, was the cutting lathe? And how close to perfect 33 1/3 was it? These issues confer obvious and huge advantages to digtial recording and playback, certainly on paper (listen up, Miss Pickler), but in actual practice they do not seem to be as significant as one would have thought. Ditto with inner groove distortion, the crude way in which stereo is extracted from vinyl (see an earlier thread about mono cartridges), and numerous other shortcomings of the vinyl medium.

This is truly a case of getting the cart before the horse ...and arguing that it belongs there.
The real issue is what performs better in actuality and not what should sound better. If we find that we are getting better results from one approach, then theorizing about why is appropriate but speculation about which SHOULD be better is pretty useless.
The question that started this discussion asked which IS better, not which should be.

Goodness me, I never realized that intra-analog vitriol was just as rampant as the digital-analog variety! But I for one don't find the arguments particularly strong on either side. And I don't think it's even possible to do a fair listening comparison of these two drive technologies, because I doubt you could hold everything else in the system constant.

Isn't the DD-vs-belt debate really a question of which technology offers the better trade-off between speed accuracy and rumble? And while not everything can be measured, isn't it true that those two things can be? So let's see some numbers--preferably independently verified. Where's the belt-drive table that is the equal of any DD in speed accuracy, and bests DD on rumble? Where's the DD unit that can say the same in reverse? Granted, this wouldn't settle the debate--measurements never do--but it would at least give us something solid to sink our teeth into.