Is Direct Drive Really Better?

I understand fully well that any approach can be mishandled or compromised by price point considerations, sheer ineptitude or misdirection. Let those units go. They are not intended to influence this discussion.
Taking the best efforts in each of the various turntable drive options into consideration, do you believe any drive system to have an inherent design superiority. Is belt slack and take-up an insurmountable obstacle? Is there magnetic influence on the cartridge from the motor as your arm nears the center of the record on direct drive tables? Wouldn't it be better to rely on constant drive of the platter rather than requiring momentum for speed stability? How the heck can an idler wheel not transfer rumble? Is chain drive really dead? Can analysis be worthwhile........?

"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.

I'll chip in a bit here. I've been using an LP12. It was enjoyable even though it wasn't maxed out. I now use a Mitsubishi LT-30, which is both DD and with a linear tonearm. The Linn provided a more spacious soundstage and great rhythm (toe-tappin'). The LT-30 sounds more emotional to me and my wife.

Seandtaylor99,
Please understand that I am not an engineer. What I pose here is speculative and lay in the extreme.
Consider that your stylus is being driven through obstacles such as a narrowing of the groove or some groove pattern of exceptional complexity. Or it is being dragged through by a belt with the aid of momentum. It seems that at the point of immediate resistance a mass no matter how great will hesitate slightly when confronted with the aforementioned obstacle. I imagine that a large motor directly driving the platter would not hesitate at this time. Further it seems that at take up a belt would stretch a bit momentarily.
As for vibration, I remember from my 1970s era audio sales days that higher end DD tables had rumble figures unimagineable to the belt drive units.

Idler-wheel drives anyway (and big DDs to a lesser extent) clearly demonstrate, in comparisons, that mass/inertia alone does not overcome stylus force drag in belt-drives. Big DDs such as the SP10 MKII and big idler-wheel drives, such as the Garrard 301/401 and the Lencos, are clearly superior to belt-drives in terms of bass depth, power and speed, and no one disputes this. This underlines a weakness in belt-drives: regardless of the mass of the platter, stylus force drag is exerting a force which is never entirely wiped out in belt-drives, only mitigated to a certain extent, which brings with it other problems, such as loss of PRaT, rhythm, timing, gestalt. This means it takes torque, an active force, a bigger motor, to combat stylus force drag, that simple mass is quite simply insufficient. Now what is clearly audible and demonstrated in comparisons between belt-drives and idler-wheel drives or big DDs - first and foremost in the bass - MUST be audible across the frequency range, and it is: dynamics and speed and attack are clearly superior, again something which most would not dispute. Now this difference in attack and dynamics is less large between belt-drives and big DDs than it is between idler-wheel drives and belt-drives, showing that idler-wheel drives go further down the road to perfect speed stability than either of the other two formats. I and others in my area (and around the world) have done repeated tests using a very high-mass Technics SP10 MKII vs various Lencos and a variety of high-end belt-drives. And no, rumble is not audible from such more highly-developed idler-wheel drives as the Lencos. Anyway, I posted reasons on "Building high-end 'tables cheap at Home Despot":

"So in a nutshell here's why I believe idler-wheel drives are simply superior (apart from the actual empirical testing which clearly demonstrates this so far ;-)). Belt-drives have belts, and these stretch and contract, and if they are not stretchy, then they slip. Not only that, but they use dinky little motors which spin at relatively low rpms, so they have neither the torque nor the speed stability of the high-rpm idler-wheel motors. Now, belt-drivers claim that simple mass in the platter wipes out stylus force drag, but since both good idler-wheels and good DDs clearly show superiority in the bass, then this quite simply shows this is not true, else belt-drive bass would be as good as that from Garrards or Direct Drives, kapish? This MUST also be audible across the frequency range, and it is, as a relative softness and lack of attack and dynamics as compared with both DDs and idler-wheel drives. The turntable with the best speed stability in practice should, given a decent platform, quite simply be superior, but belt-drives show weaknesses in all kinds of areas, therefore they are at the bottom. The finger demonstration shows this clearly ;-).

Direct-drives are saddled with low-rpm motors. Therefore, while they have superior torque and so are less susceptible to stylus force drag than belt-drives, they are at the mercy of the motors (and their imperfections) to a far greater extent than idler-wheel drives or belt-drives. The platter mass serves to counterbalance the very slow and jerky rotation of the DDs, and in comparison with idler-wheel drives, there is a consequent "dryness" and dynamic constriction of the sound which is clearly audible (the Lenco and Garrard sounding quite a bit more liquid and dynamically open).

Idler-wheel drives have motors which spin at roughly 1500-1800 rpm, meaning that the very high speed serves itself to smooth out its own speed imperfections. But when securely coupled to a flywheel-platter via the idler-wheel, the platter regulates the motor's behaviour, smoothing things out further, while the powerful high-torque high-speed motor pushes the platter through all the passages, so that stylus force drag is truly eliminated, by a combination of brute force and elegant flywheel effect. Idler-wheel drives were created specifically to combat stylus force drag, from the days when cartridges tracked at 10 grams. The largest consequence of idler-wheel drive superior speed stability?: there is simply more magic and vigour in vinyl spun on idler-wheel drives. The rest, detail, bass slam, etc., is all there, but the ability of a Giant Lenco, for instance, to draw one into the music is downright spooky, incredible, amazing. It transcends the equipment, all the way down the line. Since music is the #1 consideration in reproducing music, then the most potent music maker is the best 'table/system, the end (and yes it is superior as well with respect to detail etc. yadda-yadda). I am still agog.

The issue of whether or not one system is superior to another can only be settled by testing. With high-end designers getting into the Lenco game, then expect to see rebuilt Lencos begin to appear at high-end audio shows, and perhaps one day, me along with them."

And to corroborate this, some independent published findings at http://www.clarisonus.com/blog/?p=18

Endlessly trumpeting that all systems have compromises ignores the degree and number of compromises, and assumes that each compromise is equivalent to another, such as, for instance, speed stability has equal importance as silence. Wrong: speed stability is the single most important aspect of vinyl playback, and how can it be otherwise? Records are engraved at 33 1/3, and must be replayed at 33 1/3 to get the full intended result. A compromise here outweighs every other consideration, which can be addressed anyways by a variety of means, such as mass-loading idler-wheel drives to eliminate noise (the traditional approach), neither difficult nor especially expensive. Belt-drives, however, will always have belts, and yes, you're right Macrojack, much was made of the isolation from motor noise of belt-drives, but the much cheaper manufacturing costs of belt-drives (at least in the old sensible days), and thus increased profits, were not trumpeted. Plus, when the Linn first came out, it had more measured rumble than a Lenco by a significant amount, and yet the press trumpeted its increased silence, on "principle."