Turntable speed accuracy


There is another thread (about the NVS table) which has a subordinate discussion about turntable speed accuracy and different methods of checking. Some suggest using the Timeline laser, others use a strobe disk.

I assume everyone agrees that speed accuracy is of utmost importance. What is the best way to verify results? What is the most speed-accurate drive method? And is speed accuracy really the most important consideration for proper turntable design or are there some compromises with certain drive types that make others still viable?
peterayer
Lewm,I struggle with this statement -
"among designers of both belt- and direct-drive turntables there seems to be a divide around weak motor/huge platter vs strong motor/light(er) platter"
I have never associated high mass platters with low torque motors.
If you had said the 2 schools of thought were light platters with sophisticated speed correction or control versus high mass platters with more inertia and less speed correction that would be a more accurate synopsis in my view.
Re the Kenwood L07D and the Technics SP10mk3.
In understanding the design we must remember these turntables were built for quite different purposes or use. The L07D was an all out assault to produce a state of the art tt for home use. The SP10mk3 was designed primarily for broadcast and archival use. Consequently the L07D has one of the most sophisticated plinths of any tt manufactured in terms of rigidity, energy dissipation and ease of adjustability for accurate set up. The SP10mk3 has incredible torque, very fast start up and stop times and a crap plinth.
We dont know what was in the minds of the Technics designers - the choice of the mk3 motor may have been more to do with the fact that it was the motor used in cutting lathes and readily available at the time. What is interesting is that when they increased the torque they also increased the weight of the platter significantly from the SP10mk2.
Well, I couldn't fight the temptation so I purchased a Timeline and received it today. I turn it on, and instead of flashing once every 1.8 seconds, it flashes several times per second (maybe five or six). Does anyone else have this issue? I'm thinking it's defective, but I put it on my table and it seems to flash every 1.8 seconds on several spots per revolution, so it looks as if it's flashing at an exact multiple of once every 1.8 seconds. I check and adjust the speed with my KAB strobe and after a lot of fine adjusting I get the laser to flash consistently on one spot (and the KAB showing exactly 33 1/3 rpm). I lower the needle (I have an album, the KAB, and the timeline on my table) and voila, my table does not slow down with stylus drag. I have not yet done extended time tests yet.

My table is a diy plinth with lenco drive system,a PTP, and a VPI platter. My only complaint is that the speed adjustment is far to sensitive and therefore difficult to set.

I hadn't checked the speed in a while and this experiment seems to indicate it can drift quite easily (likely with small changes in voltage and/or frequency). I see a motor controller in my future.
We often mention the great engineers of the sophisticated turntables of the 70s and 80s. What they were thinking, why they did this, why they did that. Does anyone actually know one of these guys? Where are they today? You would think that at least one of them was an audiophile today and maybe even posts on an audiophile forum, but I have never seen one of their posts. You would also think that someone in the modern turntable industry would have bumped into one of these guys at one point, but I haven't heard of that, either.

How cool would it be to talk to someone who designed the