Does this plinth-tonearm arrangement represent "closed loop" solution ?
http://www.ebay.com/itm/112016969322
http://www.ebay.com/itm/112016969322
Tonearm mount on the plinth or on Pillar ?
Folks,
I am looking to buy a custom built turntable from Torqueo Audio (http://www.torqueo-audio.it/). They have two models, one with a wide base plinth where the tonearm would be mounted on the plinth (as usual) and the second is a compact plinth where they provide a seperate tonearm pillar to mount the tonearm. According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT. My concern is whether seperating the tonearm from the plinth would result in a lesser coherence in sound ? Isnt sharing the same platform results in a more well-timed, coherent presentation ? Any opinions ?
I am looking to buy a custom built turntable from Torqueo Audio (http://www.torqueo-audio.it/). They have two models, one with a wide base plinth where the tonearm would be mounted on the plinth (as usual) and the second is a compact plinth where they provide a seperate tonearm pillar to mount the tonearm. According to them the separate tonearm pillar version sounds more transparent and quieter because of the isolation of the tonearm from the TT. My concern is whether seperating the tonearm from the plinth would result in a lesser coherence in sound ? Isnt sharing the same platform results in a more well-timed, coherent presentation ? Any opinions ?
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The Resomat is indeed a contrarian design in that it specifically decouples the LP from the platter, whereas most platter mats make an attempt at coupling to facilitate the dissipation of spurious energy delivered into the vinyl by the passage of the stylus in the groove. This is again against the principle of "closed loop". I have the resomat too and it does bring a lot of goodies due to the "isolation" of the vinyl from the vibrating motor/platter, especially in terms of reducing noise floor and presenting a more airy sound. But music looses on the timing aspect, it doesnt sing as one, probably due to the decoupling. I have since moved to a Funkfirm Achromat which is the best compromise I have heard yet. And yes, it tightly couples the vinyl to the system. |
Throughout this thread arguments on both sides seem to have merit. I will say Ralph's data is the most convincing given that he has measurements to support his viewpoint. It would be interesting to see some data involving the turntable setup where the turntable functions from a different room isolated from the airborne and to some extent transmission through the structure of the playback room. During my college years I often listened to a system in which that was the case. In this case it was absolutely necessary or the stylus would fly off the table otherwise. We listened kinda loud! I still do. I really enjoy these kinds of discussions, always a lot to learn here. A similar discussion about spiking vs isolation of speakers on WBF is equally intriguing. Even the propagator of Stillpoints began to question his product and we all know what a wonderful system that is. |
Dentdog, There is no need to be apologetic regarding your affection for the Resomat. You have lots of respectable company in that regard. Like I may have written elsewhere, if not here, I am curious to try one myself. In the past year, I had an epiphany in the opposite direction. Since the mat (of any kind) sits in contact with the platter, more or less in the case of the Resomat, I don't think this directly pertains to the arm pod discussion. I was long an enemy of record weights and the like devices, believing that they "killed" the dynamic extremes of music, in parallel with your experience using other platter mats. Then I acquired an original record weight and peripheral ring made by Kenwood for the L07D, just to have them, since I own an L07D. By chance I have found that the L07D record weight used in conjunction with a Boston Audio Mat1 or Mat2 or the stainless steel mat on the L07D sounds much better, even more "lively", than the mats without the record weight. I don't believe for a minute that there is any magic in the L07D record weight, by the way; the experience merely suggests that my earlier suppositions were incorrect. Probably any good weight of similar mass would work as well. It's a weird hobby. By the way, I also think that maglev of the platter mostly acts to relieve pressure on the bearing and possibly contribute to a lower rumble figure, but I don't think it does much to isolate the platter, at least not in a major way. So, your findings there do not add or subtract from the debate about arm pods. I do take your point about the Terminator tonearm; because they are riding on a cushion of air that would seem to isolate the arm itself from the underlying structure, the Terminator and other air bearing tonearms could be said to mimic the effect of an outboard arm pod, albeit I do believe from what you wrote that the understructure of the Terminator is directly bolted to the plinth. In which case the coupling or lack thereof would be a function of the air pressure and other aspects of the interface between the moving arm wand and its carriage. |
Lewm, the Terminator tonearm actually pivots vertically on two contact points of an underslung carriage. This is joined to a sliding metal inverted V bearing which slides horizontally on a similar inverted arm,separated by a thin cushion of air. A pump with very low pressure allows for a long thin surface, decoupled by air. Thus the arm can pivot vertically while the sliding inverted bearing moves without resistance, [air cushion]. The support arm under the inverted bearing is attached to the plinth, with the air cushion separating the bearing from the support arm. The air cushion completely separates the inverted bearing and the undercarriage from the support arm and the plinth. As to the resomat, I have experimented with three other mats and in each case the dynamics I was accustomed to hearing were sucked out of the music.This was without doubt the most dramatic negative change I have heard in the system. The music just died. Needless to say the resomat is in place permanently. While I have formally studied physics on a basic level and have some limited understanding of airborne/foundational vibrations, in no way am I qualified to refute or support either of the theories being bandied about here. I do know however that the above methods put into effect, including the magnetic bearing supporting the platter all work to decouple all the working parts. This to me seems to reduce the chances of resonant/non-resonant vibrations being transported throughout the playback system. Totally contrarian I realize, but it works and to me it works better than what I have heard otherwise, particularly in the case of high db playback. My ego isn't really attached to this, so anyone who wishes to shoot it down, have at it. |
Dear Halcro, You wrote, "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." But that is an incorrect assumption based on all my past experience. I have been present many times, in many different listening venues, when acoustic feedback causing distortion was sound-pressure-dependent. Backing off the volume control could reduce the effect and eventually eliminate it entirely, in these instances. Perhaps this is not a problem in your house, but it is a real phenomenon in some others. In the case that Atma-sphere (Ralph) describes, perhaps conditions were such that there was no appreciable acoustic feedback, even at 100+ db. It's possible. Careful set-up and room damping can indeed eliminate or remove the problem, but that does not mean it does not exist. Dentdog, More to the point, is your Terminator tonearm mounted on your Salvation turntable or is it on an outboard arm pod, separate from the turntable? The Resomat is indeed a contrarian design in that it specifically decouples the LP from the platter, whereas most platter mats make an attempt at coupling to facilitate the dissipation of spurious energy delivered into the vinyl by the passage of the stylus in the groove. Many do say the Resomat works great, however. Which should make us re-examine the theory of the platter mat. |
I've been digging through this to the point of multiple circular thinking all leading to nowhere. My comprehension, while not fully through, does lead me to question many of the tenants expressed here, if only due to being invested in a TT/plinth?/tonearm which violates almost every principle presented here for superior SQ. Trans-Fi Terminator tonearms , linear tracker with air bearing. Salvation TT with magnetic bearing, floating for all practical purposes. Resomat platter pad which further isolated the LP from the platter. nothing is connected with respect to vibrations being transmitted concurrently during playback. Sounds great. I did follow Terry9 and place a little damping material on the arm wand to some good effect. Maybe it's my tin ears but it sounds really great to me. |
This study trumps everyone... ;^) http://www.theanalogdept.com/images/spp6_pics/TT_Design/MechanicalResonances.pdf |
You said that was correct....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. |
The trouble is that the instabilities and so forth in the Earth’s crust and other sources of low frequency vibration actually force the entire building structure, house, apartment building, converted ICBM missle silo, whatever to move like a carpet being shaken such that everything inside the building is also forced to move and all attempts to control this very low frequency vibration with damping methods won’t accomplish squadoosh. This is not to say that damping doesn’t have it’s place. I’m actually a big fan of contrained layer damping in applications such as CD transports, output transformers, the top plate of iso platforms and capacitors, among other things. Even very rigid structures and stiff materials have their place in vibration isolation inasmuch as they can help control bending forces produced by Earth's crust motion. |
We do agree on this point. We both recognize that air borne vibration can be a problem.No we don't.... I pointed out that:- If air-borne sound pressure is a problem in the turntable playback system, then every increase in volume would of necessity degrade the sound.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. |
atmasphere 4,796 posts 05-09-2016 5:00pm Geoffkait: "i don’t think anyone is suggesting that damping techniques are 100% effective." to which Atmasphere replied, "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)." Oospy daisy! In that case consider my post to be in defense of your position. As for your point about damping, I actually didn’t address damping effectiveness, only vibration isolation, in my previous post. Cheers |
Halcro. Yep, transmission, WRT vibration, means the same thing here in NZ. You mentioned transmission at resonance (FR) and at this frequency, it is obviously at is maximum since the excitation frequency and resonance frequencies are the same. At excitation frequencies below FR, transmissibility approaches 1, so we more or less get out (vibration) what we put in. At excitation frequencies above FR, we get attenuation (partial isolation} as Geoff has explained above. The further we move above FR the greater the isolation. The curve being asymptotic to zero as the excitation frequency is increased. It all depends upon the FR of the material or structure, So in your apartment wall example, the FR of the wall is well below the audio band and this fits perfectly with what has been said.... Your excitation frequencies are well above FR so no vibration would be detected. So we have the question of what is the FR of the structure of the TT or pod? If this falls within the audio band then there is a potential problem. Maybe a test would be to suspend one of your pods from a thread after removing any damping you have applied. Tap it to ascertain its FR. Cheers. |
Atmasphere wrote, "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." i don’t think anyone is suggesting that damping techniques are 100% effective. Nor is anyone claiming that vibration isolation techniques are 100% effective. However, there are two points I’d like to make. One is that - generally speaking - vibration damping techniques, e.g., constrained layer damping, are regegated to frequencies, say, above 30 Hz, whereas vibration isolation techniques, e.g., mass-on-spring methods, are primarily regulated to frequencies between 0 Hz and 30 Hz. And for the latter, vibration isolation, one should address as many of the 6 directions of motion as technically feasible for best results, not to mention attempt to produce as low a resonant frequency for the iso system as possible. Since the resonant frequencies of the cartridge and tonearm as I mentioned previously are circa 10-12 Hz then even such heroic iso means as Vibraplane and some other examples, with resonant frequencies around 3Hz, can provide isolation effectiveness of perhaps only 50-70% at 10-12 Hz. Obviously, obtaining a resonant frequency below 2 or even 1 Hz would be great. Nevertheless, one should do the best one can, including isolating the other gear from seismic type vibration, too. geoff kait machina dynamics |
Sorry, Ct. I just took another look at that photo, and I still think that the new brushed aluminum or steel pillar that holds the tonearm closest to the viewer is NOT sitting on the shelf; to my eyes it is attached to the granite base that also supports the bearing and the platter. IOW, not Copernican. Not super optimal for the other school of thought (the linkage school), either, but in that general direction. |
Ct, I if I misinterpreted the photo of the Verdier, mea culpa. But would it be possible to have this discussion without the heavy air of sarcasm and condescension? Most of us are trained professionals in some specialized area or other. And most of us must have been fairly successful in our field, in order to be able to afford the toys that allow for these discussions to go forward. I take it as a given that none of us is stupid, in other words. My eyesight may rightly be faulted, if I did not see the single photo of the Verdier correctly, but I am not stupid, either. You're certainly not the only one who is guilty of the insult approach to debate, so I apologize if you feel picked upon. Now, to get back to the Verdier, I DO feel that the OEM tonearm mount on the Verdier is a weakness of the product. It does include a sturdy vertical pillar, as you say, but then the actual platform for mounting the tonearm is attached to that vertical pillar and hung out in space (see my reference to an inverted L-shape). This allows for easy adjustment of P2S distance, but it is not the greatest idea for structural rigidity. The new pillar-shaped pedestal looks better to me, no matter whether it is attached to the granite or not. |
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.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! 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.If air-borne sound pressure is a problem in the turntable playback system, then every increase in volume would of necessity degrade the sound.The defence rests....😎 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. |
HalcroErr...perhaps you should read my post again? Or does "Transmission" not mean the same thing in New Zealand? |
The airborne stuff, by comparison, is relatively inconsequential IMHO.Correct Geoff.. 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.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. |
It’s a little bit difficult to isolate (no pun intended) the vibration caused by airborne Acousitc Waves from the vibration caused by mechanical vibration including seismic type vibration without making some rather elaborate arrangements. But if you could I’m confident you would find that low frequency seismic vibration of the type produced by Earth crust motion, traffic, subways, etc. is by far the worst offender as regards exciting the resonance of tonearm, platter and cartridge, all of which have resonant frequencies around 10-12 Hz or thereabout, well below the lowest frequencies almost all high end audio systems are capable of producing. So, the solution for Verdier and other high mass designs is high performance (very low resonant frequency) seismic isolation. The airborne stuff, by comparison, is relatively inconsequential IMHO. geoff kait Machina Dynamica |
Excellent comments Pani :^) Pani Did I read on here in the past that you owned a Nouvelle Verdier ? IMO/IME it’s very easy to fall into the trap of listening to "sounds" (Audiophile), rather than the flow of the music created by the musicians (Music Lover). I have been in these phases. fwiw - they (phases), imo can be very therapeutic especially during difficult times. But it becomes about the gear, and not the music anymore. Now that linked table is a naked design; meaning all parts easily accessible. To the "ever wanting change" vinyl audiophile - it is crack. I resisted change with it, and spent time on setup with dialogue from its maker-designer. May he rest in piece. Pani - I think your personal experience answers the question in your original post quite well ? Cheers |
Lewm Optical illusion Lewm. (an inverted L-shaped affair that never looked to be very stable, to me) An Aluminum block rigidly mounted to its plinth .....unstable ? ok...... Look again. the turntable has been rotated counter clockwise. 90 degrees. The stock pillar is still there holding up the other tonearm. The external pod is not touching the same plinth that the platter is attached to. Nothing really radical but certainly better than stock. Well ok if you think so. But "Earth" for both of them, Tonearm Pillar and Plinth that holds the Platter, is now the Vibraplane. I think you just jumped over to the other side and became one of them Copernicans with your comment ? |
Now here is a serious new turntable...I saw that video. The tonearm pods are themselves on the same plinth as the turntable if I am not wrong. So then, is this setup some type of Optical illusion ? That Verdier setup is incorrect. I have owned the Verdier too and have tried various setup configurations. In the setup cited in the link above the motor housing and the turntable are placed on different platfoms, one is on a vibraplane while other is on a regular raised platform. This may give the sound some added transparency due to the seperation but they dont sing like one. The coherency is affected, I have tried it first hand. Probably the person who set it up would never agree to this because he first of all doesnt believe this can happen (hence he set it up like that) and secondly he did not hear this problem after setting it up like that. With all those expensive tonearms, cartridges, isolation platforms, one has invested very well and it is expected that he knows very well what is doing but simple things are some times elusive |
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 Again, I tend to agree with Ralph on this one and find it hard to believe that airborne vibration, even not at the resonance frequency, has no effect on the turntable system playback. I would propose yet another simple test, similar to the one I proposed before:
I am pretty sure you could hear the music through the headphone (although it would sound funny as it has gone through the RIAA stage). |
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:-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.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. |
Verdier photo: It looks to me like Dietrich simply replaced the OEM flimsy tonearm mount (an inverted L-shaped affair that never looked to be very stable, to me) with a nice solid pillar and then attached it directly to the granite "plinth". Nothing really radical but certainly better than stock. Slaw, I may be wrong, but isn't the HW19 a suspended type? The OP's post contained a perfectly reasonable question that brought out all the usual suspects to comment. |
For me... all of this is very simple... Before one considers TT that commands thousands of $'s X 10... this person should first buy a VPI HW-19 and try all sorts of experiments. This TT, along with an owner that has the willingness along with the machinery to try all sorts of mods, will have had enough experience in which to make the OP's post irrelevant. |
Fixed Pillars/Armpods with a Suspended table ? Lewm Bdp24 I agree with both Lewm and Bdp24. So then, is this setup some type of Optical illusion ? http://www.whatsbestforum.com/attachment.php?attachmentid=19961&d=1429540940 The turntable appears to be stock to me. The Armpod has been carved to fit around the plinth. The outboard Pillar/Armpod is an accessory product made by Acoustical Systems. Now Henry says - Dietrich knows a thing or two about turntables, arms and cartridges. So Henry, any idea why Dietrich has put what looks like a fixed pillar/armpod on this customers suspended turntable ? |
Under circumstances where we fire sound at a material.....Correct....unless you define the transmission of sound through the material as caused by vibrating molecules. During Sound Transmission Testing of walls for apartment buildings, we test at all frequencies from 20Hz to 20,000Hz at SPL up to 100dB. The resonant frequencies of all masonry and combination plasterboard/stud/insulation fall well below the audio band and no vibrations are detected. Glass walls of certain sizes and thicknesses can be induced to vibrate at their resonant frequencies (20-30Hz) at high SPLs. |
Halcro accoustic excitation.... firing sound at the material. putting the material in an environment where sound is present. Ok again for clarity.... Under circumstances where we fire sound at a material..... Are you saying that the material will ONLY vibrate at its resonance frequency, assuming that this frequency is present in the sound? If any other sound frequency is used there will be NO vibration in the material? This with any energy level in the sound? |
Now here is a serious new turntable... http://www.analogplanet.com/content/dietrich-brakemeirs-apolyt-turntable-aims-be-worlds-finest-and-m... 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? Just like the famed Continuum Caliburn turntable with its arm support divorced from the platter bearing support via suspension cables and bottom magnets. They are obviously all mad....😱 |
Accoustical excitation at frequencies other than the materials resonant frequency will result in NO vibration in the material, regardless of the energy level of this excitation?"Acoustical excitation"....? I'm unfamiliar with that term in the scientific sense. Can you please explain its meaning? As I stated, acoustic theory as I studied it, related to materials science and air-borne sound transmission accepts that there are only three physical observable factors.
That is why the famed 'myth' of the glass of wine/water being made to shatter when a singer hits the resonant frequency has only been scientifically observed when the volume was increased to 115dB if I recall correctly? |
Halcro Further expansion of my last question.... Are you saying that, with accoustical excitation, the material will ONLY vibrate if the excitation frequency is the resonant frequency of the material? IOW. Accoustical excitation at frequencies other than the materials resonant frequency will result in NO vibration in the material, regardless of the energy level of this excitation? cheers. |
Halcro "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'." I want to be sure that I have interpreted your statement here accurately. What you are saying is this....A material will NOT vibrate as a result of acoustical excitation unless that acoustical excitation is at the resonant frequency of the material and that this acoustical excitation is of sufficient energy. Is this a correct summation of what you just posted? Cheers. |
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.This is an uneducated assumption. 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:-
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? For the heavier plinth and platter components of the turntable system, a resonant frequency in the order of 2-6 Hz may apply. You seem to use the term 'vibrate' as if somehow it were a different genus to 'resonate'? Not only is your understanding of air-borne sound transmission and vibration factually inaccurate, it is logically impossible. Were it true....every increase in the volume dial would degrade the sound. Let me repeat that.... If air-borne sound pressure is a problem in the turntable playback system, then every increase in volume would of necessity degrade the sound. Now there are many out there who will exclaim that this is indeed the case with their systems but as I explained previously...they are hearing the effects of structure-borne feedback...AMPLIFIED. There are tens of millions of turntable systems where turning up the volume is heard to IMPROVE the sound quality noticeably. |
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Halcro, you ask if I run OTL. Well, I did, and they sounded fine, but I decided on home brew, where cost is less of an object. Before building anything, I decided to optimize the system (instead of the pieces thereof), and found that I could improve system performance by using solid state Class A, push-pull, with low voltage rails, which allowed me to safely remove the now-redundant protection circuits from the ESL's. Amps better than OTL? Don't know - but the system sure is. |
No strawman argument from me Ralph, at least not intentionally. I’m with ya, man! But in the different executions of a solid plinth offered by a multitude of turntable makers, all attempting to advance, or at least equal, the State Of The Art, there are varying degrees of success at achieving mechanical rigidity. I was merely acknowledging that reality. The table I was referring to, by the way, is the Townshend Rock, the only table that locks the front end of the very long and flexible (in relation to the size of the LP groove) pickup arm onto the plinth, much as the back end is on all good tables. And that means every arm, no matter the design and quality. Makes other table designs look downright sloppy! |
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:
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. |
**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.** My posts were based on the information you supplied or didn't. How can I ignore facts which weren't offered? You were repeatedly asked details about the pod. Did you give them? 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? Atmasphere, you've made your point and I think everyone understands it. Why don't you go back to tube design or mastering? Unless we can figure out why results differ, there's nothing more to say. |
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. 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. |
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.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. Err...anyone ever go to clubs with DJs playing vinyl at 105dB levels? Structure-borne vibrations are by far the greatest source of distortions in the vinyl playback system. That is why the makers of anti-vibration stands (both active and passive) are successful. These stands have zero effect on air-borne vibrations. Because the induced ’feedback’ is amplified when the volume is increased....most lay people conclude that the ’volume’ has caused the feedback when it is in fact the ’volume’ that simply amplifies the structure-borne feedback which already exists within the particular system. |
Lew, **To wit, there would be a great deal of movement of the LP surface, mediated by the suspension, that could not be followed by movement of the tonearm pivot, and this would generate spurious signals at the cartridge/LP interface. On a more micro level, this principle is operative in the relationship between any plinth, suspended or not, and any arm mounting system.** Not true. On a micro level the vibrations would not make it between platter and arm with a high mass "dead" plinth. Part of the reason such plinths sound good is because they resist vibration transmission. You think this engineering principle holds true under any circumstance. It does not. It holds true if and only if part of the table is in extraneous motion and the other parts move with it simultaneously. That is motion other than normal platter rotation. High mass tables are more likely to be immune to such motion. **Reed used to make an armpod. Regards, |
True, a suspended-subchassis table will always have a plinth common to the platter bearing and arm pillar (at least as far as I know!), while a non-suspended doesn't have to, the later fact the impetus for this discussion. When I was said I would not consider a table without a common plinth, that included non-suspended tables, which I agree with the others is, in regards to the importance of the mechanical integrity between platter bearing and arm, no different than a suspended-subchassis design. How that plinth is isolated from what is below it (by springs---commonly---in suspended tables, and whatever method in non-suspended) is a related but separate issue. 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. My table was designed with this matter a very high priority, it's non-suspended plinth made of steel in the shape of a shallow upside-down baking pan, and filled with plaster of Paris, to make it much stiffer and more non-resonant than the common MDF, acrylic, or aluminum (or combination of two or all three materials) plinth. Recognize it? But the designer of this table took his intention and dedication to making the mechanical nature of his deck as stiff as possible to another level by addressing the other area of mechanical integrity in turntable/arm/pickup design, 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?! ;-) |