Why do turntables sound different?

Has, I remain wholly unconvinced.

@terry9 

and  the Micro Seiki RX 5000 I bought new, then sold about 15 years ago and recently bought back  two months ago , with its bearing in its original lube untouched or opened still moving a 36 pound platter effortlessly and quietly as the day I originally bought it new decades ago,... it gives me reason to not really concern myself with what leaves you unconvinced, biased or unable to accept . I use the proof every day , Even the well executed  inverted bearing in my Orbe Se for a lighter suspended table shows the rewards of a quieter and low friction design and well made bearing. Any of the over 40 tables I have owned or built over the last 4+ decades that shined the best to me, had better built , quieter low friction bearings.  Those that were not as close, needed massaging to reduce  the noise, lesser point of fulcrum contacts make, as well as other poor designs and sources of noise. 

@nkonor

If I remember right, he showed the Ingenium, the Volvere and the
Acutus.

Each step brought more "quietness" and "three-dimensionality".

By the way... just next weekend the AAA-Forum-show will again
take place in Krefeld / Germany. So if you want to hear this
demonstration...   ;-)

racedoc,

Thanks, I am in USA. I have decided to wait for the Technics 10R. Believe that it will be designed to take another arm of your choice. Plan on a Tri-planar 12". I think it will be a game changer.

The Rockport treatise should be compulsory reading for anyone either contemplating the design of a turntable or who is merely interested in this issue. I am not a designer of HiFi equipment but it is a compelling, albeit lengthy, read.

The most salient point of the white paper is the assertion that the turntable platform/motor unit is responsible for “50% of the music signal”.

Why is that? Well, if you display an audio signal on an oscilloscope you will see it presented in 2 axes. The “Y” axis represents amplitude i.e. signal magnitude (this is the cartridge's responsibility) and the “X” axis represents the timebase i.e. the “timeline” of the music (this is the turntable's responsibility).

The speed stability of the T/T is instrumental in holding up its half of the bargain by maintaining this relationship with the other half of the signal.

Achieving that target both in the broad and transient sense is easier said than done, as the white paper will explain.

As has been highlighted by various contributors in the posts above, parasitic vibrations related to the T/T can also affect the cartridge’s ability to perform its function thereby complicating the situation even further.

This is why T/T “motor units” always influence the final sound.

In the early 1970s, I think Linn were the first to make the assertion that motor units sound different and started doing AB comparisons with other turntables to reinforce this fact in the public mind.