Da Vinci AAS Gabriel

You can do the pencil Test:
Record on the Table-no move-with the stylus into the lead out groove- all amps activated- Volume up to 50% or higher !!:
Struck with a pencil
-at the rack
-at the platform where your TT sits on it
-at the TT Chassis outside
-at the chassis near the platter
-onto the platter
-near the needle (1 inch)
and check what you will hear through your speakers.

Real good designs will let you hear close to nothing, others will hurt your ears.
The Vibraplane is quite good, normally used for electron microscopes. They are too cheap in my opinion, normally for use in Hospitals/Labors. Cheaper than a cable...I guess when it would be "made " for High End it would cost 12.000 instead of 2000. Anyone see High End equipment in Hospitals? HRS/SRA etc. racks for life saving electronics?
No?
Any idea why?
Or you can do comparisons with Belts. Could be possible you will get better results with 1 really good Belt (Specs!) and 1 motor than with a regular belt and multi Motors. Or 1 good motor can be better than multiple average motors...
A good belt is available for 80,-- And that's High End price.

Anyway, a VP is better than nothing (worst is glass or stone)

Sorry Downunder, but NO motor in high-end audio TT's is anywhere close to what is possible regarding quality and quiet regarding vibration.
It gives a really nice insight into the subject of micro-vibrations if one gives a close look into electron-microscope techniques.
They do require exactly the very same surround conditions as a high-end TT justifying the name.
But if you or others believe their motors are quiet and literally free from vibration - well this is of course fine with me.
And of course fine with the manufacturers of your TT's as they see that their marketing is successful.
Everything looks fine from the distance - and may display nasty details if looked at too close. Its like giving the skin of a beautiful girl a close look with a magnifier - it really can spoil the whole illusion......

downunder,
why do you don´t proof my suggestion on reality? Did you talk to Mike already? Who did tell you that you cannot bring your Raven motors "under vibration control". Are you living in the middle ages believing what some spiritual voice is telling you? I really don`t get it. But if you wanna stay in this status why are you discussing improvements or are you just defending your status quo? If this is the case pls. just tell me.

I still stand by any isolation system that isolates the motors and the turntable in 2 separate domains (2 separate isolation devices) will in fact induce wow & flutter as the turntable & motor will vibrate independent of each other. This in itself must be considered. So, then we can postulate the best isolation will be a wall mounted stand with the motor suspended apart from the turntable. Unfortunately not a possibility for me and for most.

So back to basics, it is important in the design of any turntable that the motor has as little vibration as possible. This can be measured but in fact no currently published magazines in the US ever do such a measurement. Neither do they measure speed accuracy. But if I remember correctly there are some magazines in Europe which do such measurements. I wonder what motors measured best in terms of speed stability (at the platter, not motor) and in terms of vibration at the motor directly and finally how much vibration is transmitted to the platter/LP from the motor. All good questions. So now, I will also suggest a good isolation system or stand will in fact absorb vibration from the motor and also keep it away from the all important stylus/LP interface.

Now, on to the theory behind more motors. I have thought extensively about this. I am by no means an expert but put forward the following points.

Syncronizing multiple motors does have its challenges and might lead to the less is more philosophy from this perspective.

While a motor pulls the belt on one side of the pully, it in fact pushes the belt & creates slack on the other side of the pully

Using 3 motors will have a "take up motor" that will pull the belt and reduce the slack amount of belt being pushed.

Also 3 motors allows for less contact area between the platter and belt. This results in less surface resistance and less induced vibration from the motor through the belt to the platter. But also, this results in less realized torque at the platter, as there is less contact between the belt and platter. Again 2 items in conflict with each other. Ultimately you will need to let your ears be the judge. I know I have, and have spoken privately about my conclusions with my audio friends.

Back to isolation, I am in agreement that more weight on top of a stand will give you a lower resonant frequency but I think there must be some way to come to an ideal number. I forget my physics as it is over 20 years ago but for anything to isolate it must vibrate. If it is too stiff it won't work. Just think of the difference between a Cadillac suspension compared to a sports car or BMW/Audi for the Germans. One is softer on your but while the other wobbles more. Ultimately I find the stiff suspension of a car better, but ask my father and he would say to opposite.

I am using springs for my stand as many have seen. I wonder if reducing the # of springs will improve isolation. I know reducing the mass on top of the stand sounded worse as the resonant frequency rose too high. But then I might as well use less springs. I wish I remembered my spring constants etc.

That's an interesting thought Dgad. I wonder if Thomas thought of using one motor and 2 passive pulleys. Arthur K from Funk Firm uses such a scheme and calls it Vector Drive.