Tonearm mount on the plinth or on Pillar ?

Hi Fleib,

In his last post, 1st paragraph, Ralph clearly stated that the vibration is likely to be airborne.

Also, if I have read it correctly, Ralph's arm pod was on an antivibration platform together with the lathe, so I would assume most of the structure borne vibration had been filtered.

Ralph, please correct me if my understanding is wrong.

As a now departed soul was keen to point out,

"More data less wank" 

Dear @atmasphere : According with my very high ignorance level there are some things that goes against your " scientific " test:

- as @halcro posted one of your premises is that exist movement in the stand alone pillar. Why don't choose as premise that the pillar has no movement? what could happen at your scientific/theory?

- I have a premise too in my subjective " science ": that the holding cartridge tonearm must be aisled from the self TT " movements/vibrations " and air borne effects in order that those non tonearm " movements " can affect/produce additional distortions/colorations to the cartridge performance.

- according with your science my premise go against your theory because the tonearm has to vibrate exactly as the TT platter. So, if we have an integrated tonearm pod that does not vibrates at all then is wrong and add " colorations " by the cartridge.

- according that we need that the integrated tonearm pod/base has those same platter bearing vibrations. So, a well damped/dead one integrated arm pod is wrong and is wrong because till today exist no TT dead silent beairng platter.

- So, I infere from your science that it's better not to aisle/fuly damps the integarted arm pod. I don't know what I'm missing here but I'm not convinced that is better if vibrates evenly with the platter that if that arm pod stays deadly.

- other of my premises is that the cartridge must be " aisle " from vibrations as we can. Now, the ideal scenario for a cartridge ridding job is to make that job with no single vibrations, this is imposible to have/exist.

- starting from that ideal scenario next step could be to put at minimum all non-self vibraions that affect the cartridge job.
The bearing platter vibrations always affect the overall cartridge job as the tonearm/cartridge resonance frequency and the own tonearm additional vibrations and the feedback of all those vibrations and now we " need " that the integrated tonearm pod stays vibrating evenly with the bearing platter and this represent additional vibrations/colorations that are produced when in touch with all the other already generated vibrations because here exist a delay time on those same kind of vibrations and its amplitude are not exactly the same.

My God !!!!!!

We need additional integrated arm pod vibrations. Why and external dead silent arm pod is different of a dead integrated arm pod? 

is it better/worst a dead silent arm pod integrated or not? or is better the one that vibrates evenly with the bearing TT platter with all those additional vibrations I talked about??


For you and the other advocates to integarted arm pod things are so " easy " but for me and other gentlemans are not. Please re-read all the @fleib posts where I agree with.

Vibrations or dead silent?, that's the question.

Regards and enjoy the music,
R.

"The motion of the pillar"......
There you go again. Nobody is claiming that a "moving pillar" is good but you have simply assumed that ALL pillars move because you yourself have used a 'moving' pillar (which you still refuse to disclose despite my three attempts to wrest it out of you).
A properly designed armpod sitting on a well isolated rigid base/shelf/plinth will NOT move despite your ill-informed protestations.

Look at it this way then: If the pillar is motionless, and the bearings of the platter are able to move (vibrate) you still have a problem- one that is solved by a plinth that rigidly couples the the pillar and the platter bearings.
Mathematically its an associative and commutative function.

Now this is illuminating and perhaps needs an explanation from you about what you believe could possibly be 'moving' in your 3/4" solid aluminium plinth?
In other words....what did the "brace" fix that was a weakness in the solid aluminium?
This is a structural and not a mechanical engineering question and requires a structural engineering answer...

I've already explained that- several times. Right now I think you've not read this thread through.
FWIW thekong's test above is really similar to one we performed several years ago.

Atmasphere, you talked about a motor producing 90 - 95dB of noise in the room and described the vibrations as room borne not air borne. This sounds more like a seismic event than music playing, as if a bus or truck drove down your street and shook the house. We not only have 90+dB of noise, we also have the motor vibrations which produced the noise.
 

@fleib, actually, no, I didn't mention anything about a motor!! I don't know how that got started- but it might be because people haven't been reading my posts and are just reacting.

Where the vibration comes from is airborne. I don't know about you, but I like to play my stereo in the same room as my turntable. Sometimes it gets loud, and the ability of the turntable to be impervious to airborne (or structural borne, as in bass that is transmitted though the floor) is really important to an uncolored presentation. 

I suspect it doesn't matter. This seems to be more than sound pressure waves hitting the table, and we might as well be talking about table mounting in general. Why is a plinth superior in maintaining identical movement between arm and platter? Either proximity, or lack of rigidity in table or pod coupling to the base.

I have mentioned why a plinth works better in prior posts. I am now certain that they are not being read- or intentionally misunderstood as a means of promoting an agenda. So to answer yet again, a plinth that rigidly couples the platter bearings to the base of the arm insures that both the arm and platter are moving in the same plane and at the same frequency, which prevents said vibration from being transcribed by the stylus, which otherwise it is free to do.

This is why an arm pillar will always be noisier and more colored no matter how dead it is. It can't possibly be in the same plane as the platter bearings, and if you think we are talking about absolutely microscopic issues you are absolutely correct! But think about the fact that you need a microscope to see what's going on in the grooves of an LP or to really view a stylus and then its blatantly obvious that the more rigidly you can couple the arm base and the platter bearings, the less there will be any minuscule motion between them.

Its not enough that you have the most dead pillar in the world. If the platter bearings are not in exactly the same locus 100% of the time then all the effort into that arm pod is nil. And that is the fact that shoots all arm pillars down. Essentially the base upon which they rest becomes the plinth, and its simply not going to be rigid enough!

No offense Ralph, but your expertise is with tubes and modifying an old Empire table does not qualify you as a table or arm designer.

If that were all there were to it I would agree 100%!! If you think though that working with an 'old Empire' is my only exposure to mechanical issues you would be mistaken. What you are engaging in here is a logical fallacy- without really knowing anything about me, you are trying to reach the argument that because the you only know me for award-winning electronics, that somehow I must not know anything about mechanical engineering. That's not a safe place to set your assumptions or anyone else's!

Trying to make this sort of appeal does not further the debate (although from my perspective I am not debating, instead simply explaining a rather basic engineering principle that relates to LP mastering and playback); all it does is exercise a logical fallacy, and by definition that means your conclusion is incorrect. I am currently under the assumption that you can do better than that- please don't prove me wrong.