Tonearm mount on the plinth or on Pillar ?

Anyway, stand alone tonearm pod or not in both " configurations " exist distortions of many kind. Wich configuration puts us nearer to the recording?, this's the question and main subject.

This is actually easy to measure! We do it with a silent disk, cut on our lathe, which is much quieter than normal vinyl. All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge. The fact that turntables that employ a separate arm pillar are more noisy then 'tables with a proper plinth is easy to see on the 'scope.

What is the vertical angle being cut into the disc where you work ?

In theory the ideal is 92 degrees. In practice, its **about** 92 degrees. This is so because not all cutting styli are identical. They only last about 10 hours before no additional heating of the stylus will keep them quiet, so they have to be replaced. This is a bit of a procedure! Once in place the cutterhead has to be set up from scratch. This is because the previous settings that worked with the first stylus are not going to be the same with its replacement. The technique for setting up the stylus involves a lot of measurement, but an exact rake angle is not actually specified in any of the manuals. What is important is that the stylus be able to cut a silent groove. So after making an adjustment that's exact what we do, then play it back and measure the noise floor. When the noise floor is the noise of the electronics and not the surface then we know we are in the ballpark.

From this you can correctly infer that no LP is cut at exactly 92 degrees, instead, all LPs are cut at **about** 92 degrees. Its an approximation that results from the way the cutting stylus itself (which is made of sapphire) is cut. 

As Fleib writes.....which tables have you measured?
This would seem like excellent scientific data and would resolve this argument once and for all.
Could you please list all the tables, arms and cartridges and what they were sitting on Atmasphere? Photos would be good here.
And can you upload the frequency print-outs for each one?
Lastly....how do you discern the different contributions of arm, cartridge, table, drive system, arm support and isolation provisions in the data?

Dear @atmasphere:   """  This is actually easy to measure! We do it with a silent disk, cut on our lathe, which is much quieter than normal vinyl. All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge. The fact that turntables that employ a separate arm pillar are more noisy then 'tables with a proper plinth is easy to see on the 'scope.   """


Good that for you it's easy task. I think that your measure is not exactly what happens during playback because you did not use a recorded LP and we want to know what it's happening during playback in real day by day listening conditions.

Now,: speakers playing loudly?.  95 db, 90 dbs, 100 dbs?  why only playing loudly?  We need to have information as day by day real as we can not over diferent conditions.

Even playing " loudly " maybe that stand alone tonearm pod was not the " ideal " one because its choosed build material, weight or damping or whatever.

Cartridges are all very sensitive  are a microphone with high sensitivity but each cartridge is affected in diferent way for sound waves or any other kind of vibrations/resonances and depends in what tonearm are mounted.

There are several variables that are inside the whole subject. The other gentlemans have too many questions as they posted.

Yes, is very easy but in reality what you did it can't gives to us " one and for all " the scientific answer. Maybe you have to reset the methodology and take in count not only those variables we posted here but many more that has influence in the whole subject.


Good that you can take this task because " one and for all " can gives us the answer we are looking for.

Regards and enjoy the music,
R.

Raul's tongue and cheek is on the money.  The variables are endless.  Drives, motors, materials, size , shape, weight etc etc etc...

What would be nice is someone with 1st hand experience with a table that has a arm attached and a pod that can go on other side.  Of course it would have to same arm, wire, cart etc.  Of course one might find that one cart might like it one way while another the opposite.  Then if one finds a difference now the subjective equation comes into play!!!

What would also be nice if a person with some real physics background in vibration and frequencies  would chime in. My quess in regards to the connection issue moving the pod around would be, I can not imagine a cantilever, at 2.5 grams, moving a 30lb plater or a 5/10 lb pod.  In regards to pod overall movement build a jig  to get close and dial it in with the overhang.

I do not have a dog in this fight.  I do have two tables and 4 arms.  3 pods and 1 plinth attachment.  Can interchange almost everything between them.  Have two diy tonearm, which are very close, so before it is over will do like I stated above ,one on plinth one on pod same table etc.

Enjoy the ride
Tom