Tonearm mount on the plinth or on Pillar ?

According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT.

This statement from the original post is false.

The problem you are up against is an engineering issue and is very similar to that of the steering and suspension in a car. Any looseness or flex in that system results in dangerous or scary handling!

Now in a turntable how it plays out is that instead of being scary or dangerous, it works out as a coloration: the platter must be as tightly coupled to the plinth via its bearing as possible, in turn the plinth must be absolutely rigid and acoustically dead while coupling the platter bearing to the base of the arm (which in turn should have no play in its bearings). Any divergence from this formula results in coloration.

The reason is simple: if the platter has any other motion other than rotation (for example a slight up and down that might be imparted from the plinth due to room-borne vibration), if there is any difference between that and the base of the arm the cartridge will compensate (since the stylus has to stay in the groove) with stylus motion and therefore a coloration.

So if the arm is sitting on a separate structure from the plinth, it is open to motion in a different plane and/or frequency as opposed to the platter and plinth. You really want it to move in the same plane and frequency as the plinth so that whatever that motion is can't be interpreted by the cartridge.

I am often amazed at how poorly understood this concept is.
 

In a typical cutting lathe is the cutting arm mounted on the same plinth as the platter or is it on a platform ?

The lathe platter and the cutter are mounted rigidly in the same assembly. Ours is made of cast-machined stainless! That assembly in turn resides on an anti-vibration platform which in turn rests on a table with adjustable pointed feet.

By having the cutter and platter rigidly coupled, vibration entering the system does not get cut onto the LP. The same principle must be applied in playback to insure a lack of coloration. Any deviation from this formula will result in -wait for it- deviation (of the stylus) and will result in coloration.

Whether that coloration is heard and accepted as such by the operator is another matter entirely!

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. 

This statement is unexpected and seems counterintuitive, at least to me. Could you describe the tables measured? If you've seen photos of Halcro's TT101, do any of the measured tables reflect that level of isolation?

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?

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.

We ran this experiment using our lathe. The reason was we wanted to install a 12" Triplanar on the machine so we would not have to move the lacquer to a different turntable once in place- to test, simply place the tonearm on the cut.

The easy way out was to install the arm on a pillar. We found out really quick that was not the best move. Now you have to understand several things here- first, the lathe is mounted on an anti-vibration platform that is rather massive, designed specifically for the lathe. That in turn sits on a custom table with adjustable points for feet. The entire arrangement has to be by definition rather dead, else sounds in the environment can affect the cut. What we discovered is that the arm mounted on the pillar was giving us more noise than the same lacquer played back on a Technics 1200 sitting nearby.

IOW, it was not suitable for actually telling if our cut was truly silent, set up in this fashion.

By coupling the arm directly to the plinth in which the platter bearings reside the issue was solved. Apparently even though a very effective anti-vibration platform was in use, it could not prevent the arm from moving in a different plane from that of  the platter (which is the failing of pillars generally speaking, per my first post above, should anyone care to understand the engineering principle in layman's language). This ultimately required that we machine an arm mount that mounted to the plinth rather than the platform. We made our measurements using the phono equalizer in a Tascam mixer board, read by an Tektronics 465 oscilloscope. I hope this gives you some idea of how easy it is to measure this!

As to sound pressure- we get about 90-95db of noise going on when mastering. The vacuum system is enclosed in its own chamber, but still makes noise when in operation. 

Now I understand this is bad news for some and as a result there will be those that think that somehow these principles don't apply to their machine. It is true that I did not make the measurements on anything other than our lathe, but if you think the engineering principle is somehow different, or that the lathe is somehow noisier than a conventional turntable (while at the same time somehow perfectly capable of turning out cuts that are so quiet that essentially the playback electronics are the noise floor no matter how quiet) you would be mistaken, check with Mr. Occam on that one.

It is of no consequence whatsoever that we used a silent groove for this test. A groove with modulation will still experience the same noise and colorations if the arm is anchored to a point that is able to move with respect to the platter.

This is not a difficult principle to understand; IMO the resistance to it springs out of the cost of some of the machines guilty of this engineering flaw- its an inconvenient truth (especially when you consider how much harder it is to make a plinth for the platter and the arm).  FWIW, the lathe is not a cheap machine either; if we were to put it up for sale in its present state (functional tested used stereo cutting system) it would be going for over $30K. If it were new it would be pushing 6 figures. Out of necessity it has far more precision in its construction than most turntables.

Now I want to make something very clear. I'm not saying a system with a separate pillar can't sound **good**. What I am saying is that if the arm mount is integrated into the plinth it will be lower noise and have less coloration, i.e. it will sound **better**.

First we're told, **All we have to do is place the turntable in a room with speakers playing loudly and then measure the output of the cartridge.**

Then, **As to sound pressure- we get about 90-95db of noise going on when mastering. The vacuum system is enclosed in its own chamber, but still makes noise when in operation.**

All of the above?

Yes.

So. Are you referring here to playing the cut disc back on the nearby technics sl1200 in your work environment ? or did you actually mount the tonearm that was on the pillar directly to the lathe plinth?

It seems most expedient to answer this question- the answers to both parts is 'yes'. The pillar got abandoned- currently we are designing a machined bit that matches the shape of the lathe's plinth so we can bolt the arm mount directly to the lathe. In this fashion it will be impossible for the base of the arm to have movement different from that of the platter bearings.

I don't see how attaching the tonearm to the plinth can affect the 'noise'?
Surely the 'noise' is a function of the isolation, the tonearm pod mass, fixity, density and material selection as well as the tonearm rigidity.

I've explained it twice in this thread already. What part of my prior explanations are unclear? The 'noise' is actually introduced when the arm and platter bearings are able to move in different planes and rates. This is what happens when a separate arm pillar is employed.

your target in that tests and your " intuitive " premises are way diferent to our audiophile main targets and premises. So, your conclusion is not conclusive about what we want to test UNDER DAY BY DAY LISTENING ANALOG EXPERIENCES and that's why for you is so " easy to measure ". Your methodology can't fulfill our audiophile targets and premises and can't help us because the your " vision " of the whole subject is overall limited.

Actually this is not true. First you have to consider that we have audiophile intent- which you have to have if you want to do a decent job mastering an LP! Second, I think you are confusing the cutterhead with the lathe itself. The lathe is a first-class turntable that outclasses most turntables ever built, and obeys all the same physical laws. This is why adding a tone arm for playback faces the same issues as any other turntable.

In my case I want to know where is the SPL ( if exist. ) umbral where the theory start to reflect the " damage " creating ADDITIONAL colorations/distortions because the non-integrated TT tonearm approach.

As previously mentioned, I have explained this twice already in this thread. I suggest you re-read my initial posts and then ask me questions that might clarify some of the points made.

You apparently believe that all separate arm pillars are the same regardless of size, weight, construction, density and supports.
The only reason an arm pillar can

move in different planes and rates

is if it is inadequate.

They all have one thing in common: they relay on the surface on which they rest. If this surface has any motion that allows the pillar to move in a different plane than the bearing of the platter, it makes no difference how well the pillar is constructed. Its a basic engineering flaw. I have explained this before.

What was this pod that Atmasphere used and how is this motor noise relevant?

We are not talking about motor noise here! Please re-read my first two posts- I am wondering though if I need to clarify in some way due to the obvious misunderstandings I have encountered!

You are totally wrong because I'm asking for normal day by day listening enviroment in real home audio systems, I don't care about lathe or about your self targets. YOUR TARGETS ARE NOT THE AUDIOPHILE TARGETS. GOT IT?

Oh I got it alright. What you don't seem to understand is that the lathe is an extremely high quality turntable- one with a massive platter, massive plinth, extreme platform and powerful drive. But a turntable nontheless, and one that stands up to any turntable made today. You could easily use it for playback only. So you are incorrect- my targets are the audiophile targets. You need to understand this, but right now I am thinking that you have an monetary investment that prevents you from doing so.

well, with all respect to him and you he is not a regarded TT/tonearm designer and for his posts neither an audiophile.

Actually this statement is false as well. It might interest you to know that Tri Mai of Triplanar was an employee of mine years ago. Further, we've been selling a turntable for about 15 years. It started as a modified Empire 208. Its expanded beyond that now and the result is we have a copycat who was a customer of ours and the price of used Empire 208s has skyrocketed on our account. That sort of influence does suggest some regard. I'm also an audiophile- that's why I do these things. Please try to stick to the facts rather than creating hearsay.

What I have been discussing here is a pretty basic engineering principle. It is not hard to understand at all. Anyone with a mechanical engineering background will agree with me instantly. I suspect those that don't have a monetary investment that forces them to resist, but this would be like resisting Ohm's Law, if you will pardon the expression.

Air borne vibration will hit the record/platter directly, as it also hits a plinth and arm. Any such vibration transmitted via the plinth will arrive after the event. How will this insure coincident behavior between arm and platter?

Again, for what, the 4th time? The platter and arm must move in the same plane and frequency, should there be any movement at all. Likely this would be airborne induced. If the base of the arm can move in a different plane or frequency, the result will be interpreted by the pickup as a coloration or noise.

For this reason the plinth must provide absolute coupling between the platter bearings and the base of the arm, and also must be completely dead (free of vibration) for best results.

In the case of an arm pillar you have essentially a poor plinth. This is because the mass of the pillar will simply not be in the same plane and frequency as that of the surface of the platter. Since the cartridge is essentially the interface, its stylus must make up the difference between the motion of the pillar and that of the surface of the platter. This insures that there will be a coloration. Please note that the platter does not have to be spinning for to be measurable.

As some others posted you are intuitive more than scientific in this subject.
No one of us audiophiles have a lathe at home but normal TTs but because in your  simple  " test " you say that appears a " coloration " then in any inferior/normal home audio system things must happen too. That's what you infere but can't prove it.

Oh I can prove it alright- and I reported how that was done. It certainly is intuitive and also scientific. Sorry I didn't record the measurements; at the time I didn't think anyone but ourselves would be interested.

Raul, if I might be so bold, you are accusing me of being intuitive and not scientific, despite the fact that I made measurements and my comments derive from those findings, while those my accusers have none!! Does anything strike you as wrong with that picture??

When we were developing the Atma-Sphere 208, we started with a plinth that was really terrible (the stock Empire plinth). We found that by treating it with damping materials, it got better, but was far better when we replaced it with a plinth that was machined of solid metal. The benefits were enormous- this made the machine far less susceptible to the volume of the stereo as it was playing in the room; bass was improved and so on.  At that point the plinth was machined out of solid aluminum 0.75" thick.

We found that by installing a brace between the the mount for the platter bearings and the base of the arm that there was further benefit.  Now if the pillar theory was correct this would not happen- improving the coupling would make it worse! This is science after all.

"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.

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?

Nothing at all. As stated previously, the stylus does not care where the difference is between the two- if the pillar is still and the platter bearings are not, its still a problem.

- 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.

Its best to isolate the motor such that its vibration is not a problem. Its also good to insure that the plinth is adequately damped. Beyond that I can’t comment on this passage as I can’t make out exactly what you are trying to say.

- 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.

Its not ’my science’, its just science. Please reread my posts above- clearly you don’t understand them else you would not have said this.

- 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.

I’m not talking about how noisy the platter bearings might be. Nor am I talking about motor noise. Please reread my posts above as you don’t seem to have done so.

- 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.

The arm pod can be fully damped as long as it is ridgidly coupled to the mounting of the platter bearings. Please reread my posts above as you don’t seem to understand this rather basic engineering principle. Could you also explain the word ’aisle’ as it seems to be a mis-spelling or mis-use.

- 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.

Ah- I think you mean ’isolated’ when you use the word "aisle".

If that is correct, the statement above is not entirely correct. It is true that it is good to isolate the turntable/pickup from vibration as best we can, but the cartridge must be held in firm locus at any time during its journey across the LP surface. If this simple issue is ignored, noise and coloration will result.

- 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.

You don’t seem to understand that if the platter bearings are noisy, no amount of vibration isolation of the arm will prevent the cartridge from making that fact plainly obvious! I’ve serviced thousands of turntables in my life and seen that played out quite a lot. If you have a noisy platter bearing, you should replace it with a functioning unit.

My God !!!!!!

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

Your conclusion here is not logical and runs counter to real life! Do you not understand how a cartridge transcribes vibrations into an electrical signal?

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??

If the base of the arm moves in unison with the base of the platter bearings, the noise of the platter bearings will be much harder for the cartridge to pick up. If the same factor is on both sides of the equation, it can be canceled.

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.

I think the problem you are struggling with is the idea that somehow you are going to make everything perfectly dead silent.

In the real world this is impossible. No matter how dead you make it, there will always be some difference that you can’t find or fix. That difference will be interpreted by the cartridge as noise or a coloration.

Because of that in the real world a good solid plinth will beat a separate arm pod/pillar every time. Again, this is not to say that a pillar can’t give good performance, it is saying that a silent and rigidly coupled plinth will give better performance. You can’t beat the math on this one.

BTW, what I have stated above is also why an arm board on an otherwise solid plinth may not be a good idea. This is because if the arm board is of a different material as the plinth, it will be able to move due to vibration in a different plane. This is why we don’t have an arm board on our turntable.

Now if you have been thinking of a poorly designed plinth and comparing that to a separate pillar, then you are not thinking about what I am talking about at all. This is so important I’m going to repeat it:

If you have been thinking of a poorly designed plinth and comparing that to a separate pillar, then you are not thinking about what I am talking about at all.

A table with a suspension is a different story.

A suspension is irrelevant. The rigidity of the plinth is what is important. 

Unless that means something other than what it says, you're changing your story.

My 'story' has been 100% consistent through this debacle. However I suspect that my prior posts have not been read very well, or they have been interpreted in some way I could not predict.

To be clear here, the noise in our mastering environment is airborne. The vacuum system sits in a box (to suppress noise) at the other end of a rather long hose.

I understand your engineering principle, but I question the significance. Will a massive plinth transmit small main bearing movement to the arm base? Excite a tuning fork and touch it to a big rock and the vibration is turned to heat. Even if it does transmit it, the resultant arm movement will occur after the main bearing event.

You say you understand this basic engineering principle (not mine by any means BTW), but the rest of the paragraphs contradicts that statement. So I think that the first statement must be false.

FWIW, I think we can be unconcerned about the bearing noise in this conversation (although I do think its important), unless the bearing chosen has serious problems! Even the bearing system employed on a lowly 1970s BSR is relatively quiet and not a source of trouble unless it is damaged or in need of maintenance. Modern turntable bearings are usually pretty good (although I have seen some wankers in some +$20K machines, worse than those BSR bearings I just mentioned but likely that is a topic for another thread). So the real issue is airborne and structural borne vibration, which I have maintained since the inception of this thread. If you don't get that, then you've not been actually reading my posts. 

What about micro movements you allude to? Not likely, and with the same time consideration.

Sound pressure waves hitting the platter are also hitting the plinth and arm at virtually the same time. To say that a plinth will insure coincidental movement between cartridge and record also doesn't make sense with regard to time. The impact on the record player is instantaneous and rotation of the record is continuous.

If you don't understand the bit about micro movements here, then my supposition that you don't understand the basic engineering principle is confirmed. You might want to have a conversation with a mechanical engineer whilst maintaining an open mind.

If you look at your second paragraph here, obviously you understand the problem, and then like Raul did a few posts above (see 'My God!') arrive at a false conclusion not supported by logic. I find it perplexing- so I have to assume that an agenda is underlying this that causes you to veer away from what seems a rather obvious solution. BTW, the fact of the platter rotating has nothing to do with this! Again, we discovered the problem and made measurements that confirmed it; it seems that those that are proponents of arm pillars have no measurements whatsoever.

Yes indeed...because Ralph can, with the same conviction that he demonstrates his turntable theories....can postulate that OTL valve amplification is the only true path to audio Nirvana....despite the observable distortions.

For the record, this is not entirely true. I do think OTLs have advantages, else I would not be making them. But all amplification has observable and audible distortions. A topic for another thread.

That’s a direct quote. Now we learn the motor is at the end of a long hose. Does it produce 90-95dB of noise in room? If so, is this noise + mechanical vibrations?

The measurements are based on this story and now it looks inappropriate. This is the same as the music coming off a turntable?

Looks like we have no relevant measurements.

The vacuum system, along with the monitors, produced about that much sound pressure at the time. There is no mechanical vibration from the vacuum system whatsoever- all the sound is airborne. So these measurements are quite relevant. Fleib, if I can offer a bit of advice, try to craft your posts in a way that it is not obvious that you are simply trying to make the other party wrong by ignoring facts. You will have greater success.

But the "correctness" and superiority of a common plinth turntable design does presume the plinth provides an inherently rigid mechanical connection between platter bearing and arm pillar simply by virtue of it being common, too large a presumption as well as an over-simplification, I realize in hindsight. The rigidity of the plinth in different tables varies, and is a major contributor to the sound of every table. Their designers have invested a lot of time, effort, and money into either maximizing the rigidity of the plinth, or at least strengthening the mechanical connection between platter bearing and arm pillar.

As I have maintained since the inception of this thread, the rigidity of the plinth is paramount. If the plinth is not rigid, then it can talk back to the pickup and editorialize. This is no better than an arm mounted on a separate pillar.

I think we can all agree that none of us are interested in what sucks. We want the best for our ears. So can we agree that in this conversation we are talking about the assault on the state of the art? If not, the conversation is moot. Please do not bring up inferior execution as an argument- such would be a logical fallacy known as a Strawman.

the front end of the arm. Free to vibrate (how much and at what frequencies dependent on the stiffness and resonant characteristics of the headshell, arm tube, all the way back to the arm’s bearings and counterweight, and down into the main pillar), it will and does! When the end of the arm, and therefore the cartridge, the measuring device of the LP groove, is free to vibrate and resonate (especially cartridges employing low-compliance stylus’), it is surely adding to or subtracting from the output of the cartridge. That is a major source of lost or added information in the playing of an LP, and only one table in the world addresses the issue. Now do you recognize the table?! ;-)

I don’t recognize the machine, but I recognize the flaw in the thinking of it in that way as you point out. The cartridge must be held in absolute locus- the arm can’t be talking back to it any more than the rest of the machine.

That is the most unlikely scenario. Airborne induced vibrations in the platter/tonearm/cartridge synergy are virtually non-existent as the turntable world would have ceased to exist if this were not so.

This statement is false, although I do agree that structural borne vibration is also a problem and have stated exactly that in prior posts. This comment suggests to me that you have not read them.

If you think air borne vibration is not a problem you are up against the issue of the real world. No matter how dead you think a thing might be, it will always have some motion, some vibration. Its inescapable, unless you subscribe to the idea that perfection is indeed possible in this world. When I went to engineering school and for that matter elementary school, my teachers were at pains to make the point that perfection is impossible - that is why we have the term ’state of the art’. It is this latter bit that underscores how your statement in quotes can’t possibly be true.

So a proper design must take into account that air borne vibration as well as structural borne vibration exist no matter how damped the setup.

My posts were based on the information you supplied or didn't. How can I ignore facts which weren't offered?

Trying to make someone wrong is a simple technique, which weve seen on the web countless times. In so doing, the goal is not mutual understanding but simply trying to make someone else wrong solely for the sake of doing so. It does not further knowledge. IOW I don't agree that your posts were based on what you say- as far as I can see, you want me to be wrong and go away, simply so you can be right.

I'm not here to make you wrong; someone asked a real question and I answered it with the accepted and correct engineering principle. It does not matter to me beyond that, others might disagree, but they are not wrong because **I** don't agree with them, they are wrong because they lack the engineering understanding:

Assuming your results are what you say, why should we accept this as the last word on this matter? Prominent table/arm designers have reached different conclusions. You're more knowledgeable than Kuzma, Reed, or Torqueo Audio?

Reed site had a set of resonance numbers which favored the pod. They're gone now, but your anecdotes are fact?

To the latter: of course, but to be clear they are not anecdotal if backed up with the measurements; of which so far I seem to be the only one here to have caused their hand to move to get (and I hope the irony of this conversation is not lost on anyone....).

To the former: apparently, if you are saying by being correct on this subject I'm more knowledgeable, but I'm not under the illusion that because I am correct about  this that I know more than someone else. What's happening is I understand the engineering, that's all.

I've been designing tube stuff and mastering all along- no need to go back, I'm already there. I know why the 'results differ'.

It does seem though that this rather odious bubble has been popped and its contents safely dispersed without harm to the parties in the vicinity.

Most people follow this belief but if you had studied acoustics and the science of materials, you would know that materials react to air-borne sound by a mixture of:-

• Reflection
  
• Absorption (as heat)
  
• Transmission (passing directly through)
  

It is only when sound pressure of a sufficient volume (and that's important) at a material's Resonant Frequency occurs...that the material can 'vibrate'.
You do know of course that the Resonant Frequency of most tonearm/cartridge combinations is 6-15 Hz and this is well below the frequency reproduction ability of all commercial loudspeakers and almost all subwoofers as well?
It in only in this frequency band that any vibration of the tonearm/cartridge can be observed. There is no 'alternate' vibration phenomena unless you can direct us to the relevant scientific papers

Halcor, the second to last statement here is plainly ridiculous- and may be why you are having trouble understanding how this works. The resonant frequency of the arm and pickup is irrelevant- that affects tracking and the ability to play bass but has no bearing on the fact that higher frequency vibrations can be transcribed by the cartridge. Were this not so as you state, it would be impossible for the cartridge to put out anything at all!

You seem to use the term 'vibrate' as if somehow it were a different genus to 'resonate'?

It is unimportant whether the vibration is occurring at a resonant frequency or not- its vibration either way- just more of it if its at a resonant frequency.

If air-borne sound pressure is a problem in the turntable playback system, then every increase in volume would of necessity degrade the sound.

Correct.

There are tens of millions of turntable systems where turning up the volume is heard to IMPROVE the sound quality noticeably.

This statement is false.

Dietrich knows a thing or two about turntables, arms and cartridges.
And gosh....what are those?
They look like tonearm pods and did he say in the interview that the tops of the pods are totally isolated from the plinth and structure?

They look like pods but they are part of the plinth. Go look at the video again. This looks like an excellent machine! It does not support your position.

If any other sound frequency is used there will be NO vibration in the material? This with any energy level in the sound?

Correct....unless you define the transmission of sound through the material as caused by vibrating molecules.

Not in an imperfect world. I am sure the word NO was capitalized for a reason. Damping material damps, but cannot remove all vibration, unless its perfect. It isn't. Its very effective for sure, but not 100%.

No strawman argument from me Ralph, at least not intentionally. I’m with ya, man!

Got it- I sorted that out a bit later.

It really doesn’t matter much to me if people wish to create a fantasy parallel universe in which the laws of physics, evidence and data don’t exist. Audiophiles are renowned for indulging in such shenanigans.
But when some, proffer nonsense as ’fact’ without a skerick of scientific evidence and insist that we swallow it as gospel.....it begins to matter.

Halcro, we are on the same page in this regard.

Unless, that is, if you are claiming you have a damping system so profoundly effective that ***zero*** vibration is the result- if that is the case, then you will have been successful where no-one has been before and the world will beat a path to your door.

In the meantime, I am the one with the skerick (sic) of evidence (actual measurements) whilst no-one else seems to have caused their hand to move to produce any. On top of that, I get accused of having no evidence... Ironic to say the least!

If air-borne sound pressure is a problem in the turntable playback system, then every increase in volume would of necessity degrade the sound.
Correct.

The defence rests....😎

We do agree on this point. We both recognize that air borne vibration can be a problem. I've seen exactly this affect turntables in the past, which is why I went through the lengths to create the machine I did.

I also recognized that no matter what I did, I would never be able to rid the machine of all vibration, so I made the plinth as rigid and dead as possible to prevent the cartridge from being affected by what vibration there was; allowing the mechanism to work for the goal (minimum pickup of noise other than the information in the groove) rather than against it.  The result is it is quite impervious to the volume level in the room; even at 110 db the sound is still very relaxed.

@thekong, I know that test tones are less appealing, but if you substitute a sweep generator in your test you outlined, then you can produce a chart showing at what frequencies the weaknesses lie and also display the waveform on an oscilloscope, allowing for a quantitative result. This is very much what we did in our test; only we did it with a silent groove since it was with the attempt to use an arm pod where we first noticed that there was a problem. Most audiophiles don't have access to a silent groove, and you don't really need one. Whether the platter is rotating or not really isn't important, since the noise we are looking to eliminate is not originating in the turntable to begin with.

i don’t think anyone is suggesting that damping techniques are 100% effective.

Actually Geoff, I was being accosted about that very thing when I pointed out that it was impossible for any damping system to be 100% effective (perfect).

You said that was correct....
You then contradict yourself by writing:-

The result is it is quite impervious to the volume level in the room; even at 110 db the sound is still very relaxed.

The two statements are logically incompatible.
No amount of plinth dampening will avoid the effects of air-borne sound waves on the vinyl, cartridge, stylus and tonearm.
The fact that you and many others can listen to vinyl played back at excessive volumes demonstrates conclusively that air-borne sound waves have no effects on the turntable system.

Actually I'm not contradicting myself at all- merely point out that the design is successful. I assume from your post here that you did not actually read the post from which you quoted or such would have been rather obvious.