Skeletal vs Plinth style turntables


I am pondering a new plinth design and am considering the virtues of making a skeletal or closed plinth design. The motor unit is direct drive. I know that as a direct drive it inherently has very low vibration as opposed to an idler deck (please do not outcry Garrard and Lenco onwners coz I have one of those too) but simple facts are facts belt drive motors spin at 250rpm, Lencos around 1500 rpm, DD 33 or 45 rpm. That being the case that must surely be a factor in this issue. What are your thoughts. BTW I like closed designs as they prevent the gathering of dust.
parrotbee
Chris.
We all have songs lurking in our past that in some way stay with us.

Re the number crunching.

The figure given was for a perfectly inelastic collision. If the collision was perfectly elastic the new train speed would be around 99.99996 KPH. 0.00004% speed reduction.
It just goes to show that little things can influence big things, even if they are 10 million times lighter.

cheers.
Halcro and Dover are correct although both muddy the waters slightly.
Halcro, by explaining the principles of structural forces necessary to move a sufficiently large armpod and Dover by mentioning the speed-correction circuitry of a DD turntable.
Neither point is relative to the Timeline and a moving armpod.
A moving armpod will be displayed by the Timeline on a belt-drive turntable and idler both without servo control.

The mistake being made is concluding that the Timeline is measuring rotational speed.
It is not.
The rotational speed is pre-dialled into its algorithm so that the flashing strobe merely confirms any deviations.
The Timeline device actually measures 'movement' to a microscopic degree. That is why it is able to visually display the effects of stylus drag as 'movement'.
As Dover points out, in a closed-loop system, any movement of the dependent particles in relation to another will be displayed by a device designed to detect movement.
@RichardKrebs

Richard, I am interested in your impressions of my isolated armpod experiment findings. First post above with a date of 2-12-15

thanks Chris
02-12-15: Basephysics
A moving armpod will be displayed by the Timeline on a belt-drive turntable and idler both without servo control.

Henry.... time to wake up now. We need your help. We need you to pull a volunteer from your Victor "Armpod" team, and have him join forces with your Raven "tonearm fixed to the turntable" team. If he resists, tell him its in the name of Copernican good and the switch will be only temporary - maybe. Well "maybe" leave the "maybe" part out when talking to him. :^)

Basephysics - that's quite the moniker. I'm intrigued again, as I was with Parrottbee our OP(Original Poster). Is physics your line of work, hobby interest area ?

Now Henry can confirm better, but if I recall he said that the timeline on the Raven turntable moved; but that it moved slowly and consistently. This implied that his turntable although not right at 33.3, maybe a little above (line going --->) this way or below line going (<-----) this way, the speed was still stable. So for purposes of enjoying records - just fine. Is that right Henry or am I blowing smoke out my ears ? Alas I don't own the thing. Also fwiw - based on Richard Krebs train calculations I would be very surprised if any movement can be observed from what is a "normal" situation for that turntable setup with its fixed tonerarm.

So I guess it depends on whether Henry is game to play for us to find out ?

On a personal note very much looking forward to Timeltel (Professor's) next thread synopsis :^)

Cheers
Shifting away from the pod part of this thread, I am wondering whether to put together a panzerholz (clearaudio style) sandwich, or even try a different sandwich such as using acrylic instead? What say you?