Is Direct Drive Really Better?

For people like Raoul, don't forget EMT idler drives.

Macrojack, I question your conclusion. I think a better read is that both belt and direct drive can work wonderfully, but it really depends on the implementation. One is not really better, each simply has a different set of compromises.

Why is that the wisest answer to so many questions, be it CD/speaklers, cables, tube V SS above all. It is all in the implentation. There are many more belt tables, but some excellent DD ones. being from the UK and a few miles from Loricraft, Garrard springs to mind. It is hard to beat a well renovated and plinthed 301/401 and a 501 would be my ideal, if I could afford it. They seem particularly hard to beat for base response.
A different and more interesting question would be, if you were going to make an ultimate, cost no objest turntable, would it be belt or direct drive? They all really are belt drive, but is that because the extra tooling costs of DD, make it prohibitive when you are going to be selling 10's or 100's, but not 1000's of units. I think that is the reason and it would be possible to match the ultimate belt drive decks, but who knows as there are'nt any to audition.

If I may be permitted to point out something that seems to have been missed here, there is more to a turntable than speed stability, although speed stability is a very important requirement.

Another factor which comes into play is the effect of vibrations or other potential movements in the main bearing assembly(and thus the platter).

If stylus drag can affect the speed stability of a heavy platter or even a motor's torque, then it can also generate lateral movements of similar proportions, due to the angular nature of it's movements as it traces the groove. Externally generated vibrations can affect this also. Since any lateral movement allowed by the bearing/platter can materially affect the amplitude of the groove modulation being traced at the time of that movement, it can cause information loss or modification, based on that unwanted movement of the platter relative to the stylus. But wait, you say, the arm could be moved more easily because it has less mass, and I say that if the arm deflects, then you get similar information distortion as well.

Now, how does this affect our discussion?
Quite simply because direct drive motors generally(and I use that word advisedly) use their drive shaft as the main bearing, which typically does not have the precision tolerances of a belt-drive system's main bearing in a good turntable. In addition, making the platter part of a motor which has inherent vibrations as a natural characteristic is not conducive to ideal conditions for the stylus/groove relationship.
So, even if a direct drive does exhibit a slightly better measured speed stability, there are other factors involved besides that.

Also, wow and flutter are very different speed variations, and to lump them together as "wow and flutter" is deceiving at best. Wow is much less easily perceived by the ear than flutter, and 2 tables with the same "wow and flutter" specification can sound quite different, especially if one has mostly flutter, and the other has mostly wow component in that spec.

To sum up, all methods of analog drive systems have their pros and cons, and none is perfect, and implementation may be more important than basic concept.

To focus in on speed stability alone, with no discussion of other meaningful design aspects is incomplete and useless. I've heard very good sounding turntables of varying drive system designs, and also some terrible ones too.

Tunnel vision is not the most productive way to analyze componentry.

David12, if I read your post correctly, you seem to be saying that the Garrards are direct-drive (DD) turntables. They're idler drives.

TWL -- Glad you could make it. Upon looking at the design of my Technics DD, I see that there is no main bearing per se but rather a broad based rotor/stator interface. The notion of that being rocked or deviated from its center seems remote given its diameter, mass and magnetic hold. After all it isn't a pencil point on a hard disk balancing a 12 inch diameter spinning disk. With the Technics table the motor is about 4 inches in diameter and in the case of the SP-10 it is screwed to the motor assembly. Very stable.
I also wonder to what extent the gyroscope effect might assist in stability in both designs. Does the platter spin too slowly for that to be meaningful. I have observed that a spinning top is rather stable at high speeds but loses that stability as its rotation slows. Does diameter of the top add to its stability to overcome slowing? Is 33 1/3 fast enough to have this influence?
Time for Seandtaylor and the physicists to come back to the discussion. I'm just tossing out questions that I can't answer.