Richard, the information came from nowhere but simple physics, my own experiments and experience with my own large collection of record decks, and the almost universally-noticed phenomenon that high-mass record decks simply don't have the "boogie factor" that low-mass decks like the Linn LP12 (and other similar decks) have. Rubber belts react, being rubber bands or springs, if you will. As the belt stretches on one side due to the braking action of groove modulations (the greater the modulations the greater the braking action) and the continuing pull of the motor, it must eventually contract. The lighter the platter, the more quickly it will contract. The heavier the platter, the greater the energy required to drag it (mass/inertia), and the slower the reaction, which affects the bass frequencies and thus the rhythm.
As I wrote up above, this is my theory to account for what I and others have heard and continue to hear. Take for instance this discussion on this forum of the strengths of various designs in "VPI Scout or Michell Technodec?": "But I would say that I'm now a believer in the 'theory' that high mass decks rob music of the life/prat/essence of music on vinyl. I don't see that teres does anything to handle resonance other than throwing lots of mass at it and this results in a dull presentation that I personally find boring and takes away one of the important reasons I love vinyl." Add to this the HiFi World review of the Garrard: "I also strongly suspect, after listening to the very clean transient starts and stops supported by this turntable, that its high torque drive system suffers less from dynamic slowing than belt drives." Simply a theory drawn from a series of sources and personal experience.
Once again I resort to the most recent consideration of this phenomenon (which I have followed avidly ever since discovering idler-wheel drives) from a Stereo Times review of the Origin Live turntable: "I must admit to severe disappointment with the musical delivery of most of the High End turntables and tonearms beloved of US audiophiles. This was as true in 1973 as it is today. Consequently I ran Duals and ARs instead of the Thorens and Japanese direct-drives that were the rage in the mid-70s; a Connoisseur when everyone lusted for a Technics SP 10, Kenwood KD 500 or Denon direct drive. Similarly, I owned Regas and Linns when Goldmunds, Well-Tempereds, SOTAs and VPIs were the High End darlings. The overall pre-occupation with stereoscopy and with sonic special effects of most High End record players pays too little attention to the core values of musical communication. (One prominent designer even admits that he was no idea of how to design a turntable with that sine qua non of the UK design school: articulating rhythm, phrasing, tempo and drive.) Consequently I find these tables turgid, dissecting, prosaic and unable to dance: you hear everything about the sonic event except what the music means."
While this phenomenon has been noted for as long as I have been paying attention (mid-'80s), the only theory so far to account for it is that mass absorbs energy and releases it over time, the greater the mass, the slower and more drawn-out the release. I submit that it is not this (heavy idler-wheel 'tables for instance and heavy direct drives do not suffer this problem with PRaT...all dance clubs use direct drives), but simple belt reaction, the heavier the platter, the slower the reaction. Of course, anyone can react to this theory in a number of ways: 1) deny that high-mass belt-drive 'tables have any problem with PRaT; 2) PRaT is an illusion; 3) high-mass aborbs energy and releases it over time; 4) disagree with all of the above and wait for a better theory; 5) agree with the theory. There are probably other reactions, and I'm sure at some point I will discover them. I read all record player reviews I can uncover (it is a sickness with me), as I find the whole "design's impact on the music" thing fascinating. I experiment extensively at home, and listen to various decks when I can in other systems. It's that "magic" factor that I find supremely important in music, and I believe this comes down to timing, or PRaT, as does the above reviewer and Art Dudley, among many others. The pursuit of high mass in record player design is a runaway train with no musical (PRaT) foundation.
