Has anyone had trouble with speed on their tt

Technically whatever it is the proof is in the play back, one outstanding example that will shock anyone that thinks they are familiar with this outstanding RCA Living Stereo recording is Belafonte at Carnegie Hall, Belafonte's vocals are much different, it will stop you in your tracks.
I'm not claiming that I have any answers why this Lp sounds the way it does including others that I thought I knew well, but I think this goes beyond having a table that is capable of precise speed no matter what is going on in the music.

Omsed.
If you are observing dynamic speed changes, greater than 1% in a closed loop system, I would suggest that the TT is poorly designed or malfunctioning.

But thanks to everyone for the thoughts. I had bought Origin Live's best tranny/motor DC200/and motor controller and had problems so I bought a second complete O.L.system and had them both turning a heavy steel Aerex flywheel. The VPI tt was updated to the super platter that is now defunct. It was driven with belts and I tweaked them for just the right tension and everything lubed and leveled and was always unhappy with my speed. My McIntosh 831MVP blu ray player with Upgrade Co mods cannot touch Expressimo's turntable and motor. Plus Mac had trouble with the transports and it took a long time to get mine back after owning it less than a year. Digital does have excellent speed and if you get a good modder like David Schulte to shield it properly you can take the jitter out of the digital system. My vinyl still bests it by a good margin.

Mosin You might be onto something about the platter being so important to speed control.

Google cog free , Ironless rotor , encoder with absolute Position,,, http://www.aeroflex.com/ams/motion/datasheets/motion-motors-zerocogging.pdf