Direct Drive is never on speed always hunting and searching
In order for a 'table to have low flutter, the rotational precision must be high. It is an undeniable fact.
There are two kinds of direct drive systems out there:
1. those that use positional updating systems.
2. those that use linear frequency generators.
The 'tables that use the update technique will make a correction to the platter speed once, maybe twice per revolution. These designs will appear to hunt and search for speed because the corrections are large and tend to overshoot. They also will exhibit high Wow and Flutter Test results, usually over 0.2%. You know them as the DJ variety, Stanton, Gemini, Numark, etc.
Linear frequency generators like those used by Technics, Denon, JVC and Kenwood to name a few, have a constant read on the platter speed and do not need to make any corrections unless it is truly neccessary. And since these systems know the precise instant that the speed has changed, they can make a correction that is timed properly without overshoot and, as a result, is imperceptable. These systems acheive Wow and Flutter results of 0.025% and that is really nearing the resolution of the test equipment. These drive systems were born in the discrete quad period 1972-78 where the need to lock onto a 30Khz carrier signal and trace modulations to 50Khz at the inside groove were a requirement.
To compare, a very good belt drive like the Well Tempered Turntable, reviewed fully by Audio magazine, shows a Wow of 0.12% and a Flutter of 0.03%, or W&F = 0.15%. ca 1988
There are few measurements of this type specified by todays new age manufacturers or done by magazines today.
One I found a few years back in Stereophile Magazine reported on the Music Fidelity turntable around $5K, Flutter only equal to 0.15%. Interestingly, the magazine would not publish the Wow figure, expressing doubts about the measurement, believeing it was too high and probably the result of record non-concentricity. Perhaps, still, it would have been useful to know what was actually measured. 0.15% is 5 times the flutter of the W.T.T.
Now go back and compare that to the Technics W&F at 0.025%.( That's wow and flutter combined remember. That's 5 times better than the W.T.T)
Those measurements would not be possible if the motor was "hunting and searching".
And it is the only kind of control system that can compensate for dynamic stylus drag as well as static drag. Further, Technics goes so far as to test for spurious or peak wow and flutter as well. The results for that measurement is still just 0.035%! These specs are in the owner manual.
Of course, there are those that will continue to delcare that while direct drive systems measure better, they do not sound as good as belt drive. We all should know that blaming the drive system alone as the single cause of poor sound in a turntable is an incomplete analysis. It might actually be more useful to understand what high levels of flutter actually sound like, and why that sound may be more acceptable to some and not others..
The following link from Answers.com reveals some interesting audibility data that results from only modest levels of flutter and it is worth reading.