Where do classical vinyl records get their rumble from?

@rauliruegas 

"as a true you need to measure the tonearm/cartridge resonance frequency through maths:"

This goes without saying as part of your initial set up procedure but it will never work unless the cartridge wasn't properly chosen for compliance and mass in the first place. Secondly, why doesn't everyone equate warp information with rumble? Rumble is a mechanical artifact of a poorly designed, machined or damaged main baring and as the plater spins on it, the noise is transferred up through the platter and the vinyl and is then picked by the cartridge and often sounds like a faint cyclical roar in the background during quieter music passages. I used to think it was groove roar until I started moving up in the quality of the turntables I was using that had much better fabricated main baring's thus the phenomenon became forever inaudible.

@faustuss Since the mid' 90's I developed an interest in improving a Platter Spindle Bearing, where a Garrard 401 was the first Donor Model.

The work done by Dr Martin Bastin, proved very worthwhile; too many years are now passed to suggest I recollect the improvements, but there was enough from the experience to set me on a path of discovery, where a Stethoscope was used to assess the work being done.

The next challenges were worked on with Lenco ID TT's, and later this was to become the foundation for work done on Vintage Japanese DD TT's.

The loss of noise and increase in detail, dynamics and envelope have always been the end result. 

The idea of removing metal on metal and extremely tight tolerances in use for alternative materials if common used metals has been a substantial contribution.

A spindle rotating on a much improved axis at substantially reduced friction. This is created through the design, where the spindle is seated upon non-metal low-friction material, and the spindle is contained within non-metal bushes which are custom measured to the spindle and allow very low micron tolerance. Combining these control measures is also another substantial contribution. 

I am in full agreement that measures put in place to improve how the Spindle interfaces with the bearing housing and platter will substantially reduce the noise floor, resulting in a major improvement to the end sound; details, dynamics and envelope become discernible and easier to detect their presence in the structuring of the produced sound.     

@pindac 

"a Stethoscope was used to assess the work being done."

Yeah, but we don't listen to music with stethoscopes.

@faustuss

" This goes without saying as part of your initial set up procedure but it will never work unless the cartridge wasn’t properly chosen for compliance and mass in the first place. Secondly, why doesn’t everyone equate warp information with rumble? Rumble is a mechanical artifact of a poorly designed, machined or damaged main baring and as the plater spins on it, the noise is transferred up through the platter and the vinyl and is then picked by the cartridge and often sounds like a faint cyclical roar in the background during quieter music passages. I used to think it was groove roar until I started moving up in the quality of the turntables I was using that had much better fabricated main baring’s thus the phenomenon became forever inaudible."

After some thought I attempted to edit my post for grammatical errors but @pindac was about to commit his comments which superseded my edits before I posted them. So here they are.

...it will never work if the cartridge’s compliance and mass wasn’t chosen for the tonearm’s in the first place. The resonance will forever be too low or too high which will either accentuate warp information if too low or affect tracking and bass response if too high. 

Secondly, why does everyone equate warp information with rumble? Rumble is a mechanical artifact of a poorly designed, machined or damaged main bearing and as the platter spins, the noise generated is transferred up through the platter and the vinyl and is then picked by the cartridge and often sounds like a faint cyclical roar in the background during quieter music passages. I used to think it was groove roar until the quality of the turntables I was using improved and had much better fabricated main bearing’s, thus the phenomenon became forever inaudible.

Oh and @pindac, thank you for the plagiarized and carefully edited AI information you posted up thread from me. 

If one's experiences shared is plagiarism? Especially experiences referenced on many an occasion on this forum over the years of being a member. Hey, ho, each to their own on how they assess this.