Turntable speed accuracy

Gosh, what is left to say or think after that?
I agree that direct-drive turntables can be highly "colored", in a bad way. I also completely disagree; speed stability is the sine qua non of a turntable, no matter the drive system. "Sound quality", if by that term you mean the degree to which the sound emanating from the speakers can be made to emulate "real life" does depend very much upon speed stability. From that comes rhythm. From rhythm comes verisimilitude, in part.

Sure, a tt with excellent speed stability can sound bad for other reasons.

Why is a battery power supply, per se, likely to be superior to all other approaches to power supply?

We have pretty good reports from TW Acustic owners, who have changed the standard PSU with battery motor control unit from Raven Black Night.

No variable ac line = no variation in motor control = better stability.
Problem for many dd turntables IMHO is the fact that the motor MUST control (by nature here ..) the platter very direct with minimum delay.
Thus the use of a heavy platter with high inertia is counterproductive to direct drive.
IMHO however, high mass platter made with some insight in energy transfer and damping have inevitable positive effect on analog reproduction.
A DD with high mass platter "looks" at a similar problem as a BD.
aBoth have a kind of "overhang" in their reaction between motor speed adjustment/correction and reaction by the platter.

To resolve this problem some BD makers use optical feedback - to measure the platter speed and adjust the motor speed "in time". I think the new "Micro Seiki" spaceship is equipped with such a speed management system.

Dear Thuchan: Please read this about " neutral ", this add more sense to what I posted and telling you that I'm not alone, btw your dear friend Syntax agree too:

++++ " Takeda San says, "I was always frustrated by modern cartridges -- including my own designs in the past -- because they always sounded clean and nice but failed to present a very important element of music. What was missing was the linearity of dynamics. Many cartridges can produce clean sound but the sound is only one element of music. They fail to present the flow of music. Listeners may not realize this if they are not familiar with music that requires a wide dynamic range and delicate gradations within it. Large orchestral works and certain piano recordings are typical examples. I also wanted my Standard to be tonally as neutral as possible. Many cartridges have some degree of coloration to make them sound appealing. I didn't want to do that with the Standard."

of course that you don't have to agree with the " neutral/accurate " subject as Takeda San said: ++ " have some degree of coloration to make them sound appealing. " ++, if you are on this side good for you because that's what you like it. Neutral/accurate is in the other side of " I like it ", neutral/accurate is the way " thigs " must be it does not matters if we like it or not.

IMHO, if you own a good audio system and you don't like neutral/accurate performances then that " good " system has one or several problems else where, or your ears or both.

Re-read Frogman's post and if you have time my post too and some Syntax ones on the subject on other threads.

Regards and enjoy the music,
R.