A Copernican View of the Turntable System

Hi T_bone,
I realise that you, and many others are perhaps trying to rationalize what we 'arm-pod' folk report, against what your instincts and learnings tell you and all I can really say is that until one actually tries a well developed 'pod'.......it's all just 'words'.
But I'm looking forward to your own experiments :^)

Regarding your problems with 'feedback' and my lack of any discernible angst in that region.......I must say that I have always had my turntables mounted on a shelf cantilevered from a solid masonry wall.
The fact that you state that..."even when my P3 is well away from my speakers"....... leads me to suspect that it is structure-borne feedback you are experiencing rather than air-borne?
Could you perhaps describe how your P3 is supported?

T_bone. How could anyone of impecable taste listen to their turntable with the lid down :-)
Even with my lp12 music sounds much better with the lid up, or better still off. Never even thought of playing the exclusive P3 with the lid down.
But seriously, a great thread that makes cd /digital even more boring

T_bone,
Re-reading your post above.......

That said, if I implement pods, I will seek to couple the pod and the motor to a single rigid surface, and then isolate that rigid substructure.

I believe that I have done just that by coupling (or de-coupling) the motor and pods to the very same 32mm laminated (stressed-skin) rigid shelf structure which is isolated from the floor and walls by cantilevered metal brackets.
Your statement and that of Jonathan's are not quite the same?

Dear Travis, Once you couple a high mass arm pod to the plinth you likely have a very good set-up. That's what I would do if I ever build an outboard pod. I never would argue that basing a tonearm firmly in a stabilizing high mass is not a good thing. Look at those optional weights made by M-S and SAEC to stabilize the vertical shaft of their tonearms where it passes through the mounting board. That seems like sound engineering to me. I have made some brass pieces like that (to go under a mounting platform) for my DV505 and I plan to do it for the Reed and/or Triplanar.

Halcro,
I know my statement and Jonathan's are not the same - no 'quite' about it. My 'if I implement pods' comment involves a pod, his doesn't. I agree with Jcarr's recent comments and am on record moons ago on these fora having said something similar. But if a pod is to be used, having everything extremely well-coupled (de-coupling I assume is isolation, which should be avoided) and rigid will approach JC's suggested goal. Some pod implementations have different isolation systems under the pod and the table, which makes for a different arm-bearing-to-table-bearing interaction, and this is something I would suggest against. In the end, it all comes down to implementation (Dgob's Chinese cats and your arm pods).

'Well away' is perhaps different than what you would call 'well away' given the concept of 'distance' in a Japanese living space is probably different, but it is still out of the direct radiation pattern of my speakers. My P3 is on a large wood rack, but it does not matter much. The P3 has construction, shown here much like Jonathan's suggested method, with an isolation platform built-in. The fact that results differ slightly with the top down suggests air-borne effects, but I have no doubts my room could be improved.

Downunder,
The lid of the P3 is specifically designed to combat airborne vibration which might affect playback.