Where do classical vinyl records get their rumble from?

@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.   

@rauliruegas 

Thanks for the link to the Vinyl Engine’s resonance calculations.

I must emphasise that the noises I hear on various records are pretty much the same on both my decks. I am convinced these are artefacts on the records, not in my playback system.

However, just for background information, I tried to measure arm/cartridge resonance for both decks, just using the Tacet test disk.  Only the Holbo showed any resonance, at 6-Hz, and I think that is due to the 55-kg sub-plinth, sitting on sorbothane hemispheres, not the cartridge / arm.  The Garrard sub-plinth does not sit on hemispheres.

At no time do my speakers show excess excursion, which I would expect to be a result of real resonance issues, even with a high compliance Shure V15 type III cartridge.

I am having a few issues when trying to use the Vinyl Engine tabulated data:

1. DS Audio does not publish compliance specifications
2. A review of the DS003 claims compliance of 7 × 10⁶cm/dyne at 125-Hz
3. The Vinyl Engine calculations require compliance measured at a frequency of 10-Hz
4. I estimate the DS003 (7.7-grams) with bolts weighs about 8-grams
5. As a tangential tracking arm, the Holbo has different effective masses vertically and horizontally
6. With Holbo’s 7.5-gram effective vertical mass, the Vinyl Engine table gives resonance of 15-Hz
7. The Holbo has an actual horizontal mass of 31.6-g, and the table gives resonance of 10-Hz 
8. The Audio Technical VM540ML has compliance of 6 × 10⁶cm/dyne at 100-Hz
9. I estimate the VM540ML (6.5-grams) with bolts weighs about 7-grams
10. The SME Series II improved has 6.5-grams effective mass
11. With the SME 6.5-gram effective vertical mass, the table gives resonance for the AT cartridge of 17-Hz
12. The Shure V15 Type III has a dynamic compliance of 22 × 10⁶cm/dyne but no frequency is specified
13. I estimate the Shure (6.0 grams) and bolts to weigh 6.2-grams
14. With the SME 6.5-gram effective vertical mass, the table gives resonance for the Shure cartridge of 10-Hz

The biggest unknown for me is the way dynamic compliance varies between 10, 100 and 125-Hz