garrard vs clearaudio innovation

How good is speed accuracy and rumble on Idler drives?

I have four Velodyne dd18+ subwoofers, in stereo bass stacks outside of my Focal Stella Utopias. Turntables are Kodo the Beat and Artisan Fidelity 301 Statement.
I get zero rumble from either, and i play bass driven electronica - deep house, drum and bass, hip hop- at valley-shaking volumes.
Rack is an Artesania Esoteryc (sic)

tzh21, speed accuracy can be excellent but they will always be noisier due to the multiple moving parts. Even if they start off relatively quiet wear on the idler wheel will eventually increase the noise (rumble).
Idler wheel tables persisted in the commercial world because it is easier to cue an idler wheel table. If you don't know how disc jockey's cued records, they held the platter still with their left hand, placed the tonearm on the record at the beginning of the cut they wanted to play then "jockeyed" the platter back and forth to the very beginning of the cut and right on time they let the platter go. Finally the idler wheel tables were replaced by direct drive units which were even better at this. You can not use belt drive tables this way. 
gavman there is no such thing as zero rumble in a turntable.

mijostyn

If you don't know how disc jockey's cued records, they held the platter still with their left hand, placed the tonearm on the record at the beginning of the cut they wanted to play then "jockeyed" the platter back and forth to the very beginning of the cut and right on time they let the platter go. Finally the idler wheel tables were replaced by direct drive units which were even better at this.

Actually, the pickup speed of a good idler like the old QRK broadcast tables is faster than a DD, and why idlers persisted in broadcast well into the DD era.

You can not use belt drive tables this way.

Sure you can. You "slip-cue" by using  a slip mat, which lets the platter spin while you hold the disc steady, and then release the disc when needed. Many radio DDs had slip mats on them for just that reason.

Slip mats were used on direct drive tables cleeds. Belt drive tables generally do not have enough torque to get started IMMEDIATELY like a cuing table needs to. You need to practice your disc jockey exercises cleeds and stop sticking your nose into things it nose nothing about:)