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
The platter also does not keep rotating very far after the motors are switched off indicating perhaps a bearing designed for friction so that the motors have a load against which to pull?

Halcro, I can't think of a reason for a bearing to provide drag in a turntable- that seems like a Bad Idea to me. Are you sure the bearing is OK?
Use of a capstan, etc, or any strategy that increases the area of contact between the belt and the platter is a good way to combat "belt creep", the bete noir of belt-drive tt's. This is why I am skeptical about 2- and 3-motor arrangements; of necessity, the platter to belt contact area is reduced in both cases, even compared to conventional single-motor arrangements. This is also why I really like the Artemis SA1 turntable, in principle. (Never heard it.) It uses a single motor and a capstan so that the belt (looks like tape) is nearly completely in contact with the circumference of the platter.

Dare I say that a device like the KAB might be superior to the Timeline for detection of very transient deviations in speed? OK. I said it.
Halcro, I can't think of a reason for a bearing to provide drag in a turntable- that seems like a Bad Idea to me. Are you sure the bearing is OK?

What style bearing is in the Raven? I remember reading about it some time ago... something about it being oil-less or not having an oil reservoir or something like that. Halcro?
There are a couple of different bearings used in this table, the latest version being different and older versions not upgradable. Well you could but you would also need a new platter.

The bearing in the BK has what looks like a ball bearing on the top.
Dear Halcro: You always can try a different thread's build material and see/hear what happen.

regards and enjoy the music,
R.