Direct Drive

@billwojo it is wow and flutter. 

Here are the specs for the Technics 1210G DD TT

Rumble is motor noise.

 Type: Direct Drive Manual Turntable
Turntable Speeds: 33-1/3, 45 and 78 rpm
Adjust Range: ±8 %, ±16 %
Starting Torque: 3.3 kg-cm
Build-up Characteristics: 0.7 s. from Standstill to 33-1/3 rpm
Wow And Flutter: 0.025 % W.R.M.S. (JIS C5521)
Rumble: 78 dB (IEC 98A weighted)

Now here are the spec's for a 1975 Thorens TD145

Specifications

Drive system: 16-pole synchronous motor with belt drive

Record speeds: 33⅓ and 45 rpm

Turntable platter: 12 -inch non-magnetic zinc alloy

Rumble : -48 dB (unweighted), -69dB (weighted)

Wow and flutter: 0.06%

Looking at these spec's you will not hear either.  Like I said it is a silly argument. Also someone made a comment about changing belt, how hard is it? Not hard at all. Speed on my 47 year old turntable is dead nuts on. 

Terry, I am well aware of the assumptions we make when we speak of turntable speed and its accuracy or lack of accuracy. But if you categorically prefer BD turntables, with or especially without a dedicated motor controller, it’s not because BD turntables are more speed constant than a well designed and constructed DD turntable, in my opinion. And I assume your experience is limited to a few examples of each type, as is mine.

@juanmanuelfangioii Do you believe that a motor upgrade, like those from Origin Live, would make noticeable improvement with a Thorens TD 145? It does seem that a belt driven table lends itself to more upgrades and refinements than a direct drive table but that may be due to my lack of knowledge.

@goofyfoot I really do not have an opinion on the Thorens Origin motor upgrade. I have the original German 16-pole synchronous motor albeit it gas been cleaned and tweaked a bit, polished bearing....it is dead silent and over 40 years old.

If it isn't broke don't fix it. 

Listening to it now and I am still amazed how these 40 year old turntables can give the modern stuff a run for their money.  

@terry9 

I may have misunderstood you, but you mentioned that "there is no such thing as instantaneous speed measurement in the real world":  AnalogMagik software does measure instantaneous speed.  I think Fremer may use it, or possibly have some other software by which he determines the variability and stability of speed control of the turntables that he evaluates.