Why do turntables sound different?


Let's consider higher-end tables that all sound excellent. Same arm/cartridge and the rest of the chain. Turntable is a seemingly simple device but apparently not quite or not at all.
What do members of the 'scientific community' think?
inna
You were wondering why tables sound different. I mentioned the bearing because it is an often overlooked component that enormously contributes to sound quality. 
The bearing design comes into play , after the design of the table and materials and lower or higher mass are given. Then the appropriate bearing is designed for those criteria and used to suit specific scenario. Look at the mass and close tolerance of a micro seiki bearing , and the lead impregnated lube it utilizes for a massive platter and mass record weight ability. You wouldn't use it to spin a rega platter. Even the lubricant on some tables is chosen to offer more friction with the intention it will help with speed stability (+ - drag). As long as the bearing can carry the load upon it, and do it effortlessly with no chatter/vibration, the motor and the power supply will champion or fail the best of tables. Its not about speed accuracy , your ears are much more agile at spotting fluctuation than a steady slight slow or fast rpm. Where the belt rides in relation to the bearing/spindle point is more critical than some tables / owners realize as well.
It all , still , like it or not boils down to the materials chosen as a whole, the design to implement them and the drive used. No matter how much more is spent for better materials, higher quality of machining parts, tighter tolerances and better power supplies/motors and esoteric materials better suited at rejecting vibrations,
and tone arms ......it still is at the mercy of the home environment and the ability of the end user to make it sound "different". Different in these terms would be to that specific user as being "better" as the reason of personal choice.
However, if that user is not truly skilled at set up of the table, the arm , its placement and the treatment of the room the previous means nothing.

As I said in my prior post before, there are 2 reasons. The biggest reason IMO and IME for "different sound " is the end user him/her self. These days many dealers lack real skill with set up . The designers build tables to cost and sound how they think is best (different) . Different is simply the factors of personal taste for looks and sound as well as individual price points of choice.
You don't need a scientist to tell you if a chunk of aluminum will ring louder and for longer than a slab of panzerholz.
Bearings...interesting.  I'm actually considering a bearing upgrade on my SL-1210.  I have a choice of two bearing designs:

* optical grade Sapphire-Ceramic bearing from The Funk Firm

* The Timestep bearing has the spindle as a solid single piece of polished 303 Stainless Steel with a much larger base diameter and the bearing is polished PB102 Phosphor Bronze. A silicon nitride ball and PTFE thrust pad are fitted. The whole assembly is in a captive oil bath so that you can use more suitable thin oil, or any oil of your choice.

Any recommendations?
Without knowing more about it the sapphire/ceramic design should have far less drag.