As to suggestion #6:
6. For fine VTF adjustments don’t futz with the counterweight, there’s an easier way. Set the counterweight for the highest VTF you think you’ll need (ie, close to the pivot). Pick up some 1/4" I.D. O-rings from Home Depot. To reduce VTF a bit just slip an O-ring or two on the end stub. Thin O-rings reduce VTF by .01-.02g, thick ones by .04-.05g. Quick, cheap, effective. (For safety, always lock the arm down while adding or removing O-rings.)
I don't understand why you are using o-rings when it is easy enough to use the counterweight system to make fine VTF adjustments. You should have a small weight that screws into the end of the tonearm. The way to make fine VTF adjustments is to unscrew the small weight when you want to decrease VTF and screw in the small weight when you want to increase VTF. I haven't had any difficulty making fine VTF adjustments using this technique, and it seems easier to me than slipping on (and off) o-rings. |
12-06-09: Thom_mackris
Yes, you have to unmount the arm to remove the trough, and yes you want to remove the support bar. The idea is to eliminate a vibrating tuning fork. You'll be removing two small, straight slotted jewelers' screws.
From my perspective, I would say that this idea of taking apart the tonearm to remove the trough is very inadvisable. First, the trough and support bar are VERY rigid. Second, to test my intuitions, I did an experiment in which I tapped on the trough with a screwdriver to test for resonances. There were none. The trough and support bar is no tuning fork. |
Jfrech:
When I tap on the trough, I hear a *sound* but a sound is not necessarily a resonance. The sound that I hear when I tap on the trough quickly dissipates. Now, you can impart a lot more energy upon a tonearm part with your finger (or a screwdriver) than can ambient sound energy from your speakers. So, what that means is, when resonance is lacking, sound energy has no chance of having any impact on the sonic performance of the tonearm.
Resonances are something different. What is different about a resonance, and why resonances are such a problem, is that when a resonance exists, sound energy is trapped within the object, which then becomes a source for additional sound propagation. In effect, sound energy that enters the object tends to stick around for a lot longer. That's why the tone that you hear from a tuning fork hangs around so long - it's because of the resonance at the tuned frequency of the tuning fork. On the other hand, other frequencies tend to get wiped out rather quickly, so that's why you don't hear them.
I can't, and don't, comment on what people think they are hearing. For example, I will not tell you that you aren't hearing what you say you are hearing. I simply lack sufficient information to make such a statement. The question that I ask myself is: "is there an explanation that is based in sound physics or electronics reasoning that explains what people say they are observing?" |
08-27-10: Dougdeacon
... ultimately what counts is whether a person knows what they are talking about.
Agreed. In this case the measure is how music sounds with and without the trough. We know. You don't.
The OP requests that you avoid further postings on his thread, which he started to help people willing to help themselves, not to argue anyone into something they're unwilling to try.
What I know is what you say you hear, but you have failed to give a logical explanation as to why you are hearing what you say you are hearing. As it turns out, some of us have other things to do rather than to spend all our time listening to a wide variety of audio equipment. Since some of us have limited time, we need to cut down the search by pre-screening down to a set of logical candidates to investigate from the wide variety of available audio equipment that is sold. That's why I look for logical explanations, because that is how I get clues as to what is worth my while to investigate further. Don't get me wrong, I think that there is a limit to what you can learn from objective data. If you want to optimize a system to your specific tastes, you can only do that by listening to the actual equipment. But you should understand that there are real limits to subjective evaluations: they are subject to being colored by various preconceived notions. That's why you, and audiophiles in general should learn more critical thinking about this stuff. You will find that seeking out objective information and data to support your subjective assessments will help you in your own evaluations. Ultimately, what you do is up to you. But what I am telling you is that when you post your opinions on public forums like this one; those comments are going to be evaluated by people like me based on whether subjective comments can be supported by an rational explanation (or at least some evidence of reasoning) of why you might be observing what you are observing. In my mind, relying on well-worn buzzwords just doesn't cut it. |
08-28-10: Thom_mackris
Dear Paperw8,
You went to the effort to quote my comment about the the THIN BAR to which the trough mounts, and then conveniently side-stepped my point by IGNORING this bar and turning your attention to the trough itself.
The (relatively) heavy trough hangs off this (relatively) flimsy bar. I don't have time to make this any more obvious to you.
What is obvious to me is that you have a different tonearm than I have, because on my tonearm, the bar is rigid. In fact, the entire assembly of the trough and bar is rigid. It does not look like "flimsy" construction to me. You didn't say what it is that you design, but it doesn't appear to be electronic equipment (then again, judging from your comments about quantum mechanics, I gather you aren't a physicist either - as it turns out, I took a class in quantum mechanics when I was in college). If you look at the specifications of some audio equipment, you see that some makers list data that seem to have no practical value other than to look impressive. For example, the frequency response of an amplifier at 200KHz is of no significance to me - I can't hear frequencies that high anyway. This is the point, you try to sort out what matters and what doesn't matter from the constant barrage of claims that you see relating to audio equipment. To sort it all out, you need more than buzzwords; you need good data and information. You say you're hearing what you're hearing. I'm not saying that you're aren't hearing what you say you're hearing. But if you can't give a logical explanation for why you are hearing what you are hearing, your opinion has less value to me. On the other hand, opinions that are attached to some rationale have more value to me. That's not being dismissive, and that's not being closed minded that's just my saying that you haven't given me enough information. I ask for a logical explanation and all I get are "wizard of oz"-type assertions of "we know what we're talking about! Don't question our knowledge!" Neither you, or anyone else here, owes me any specific information but I do evaluate information based on the extent to which it makes sense to me. I mean, when I read stuff on this forum, one reaction that I have is that I find myself thinking with amazement over how some guys seem to blow a lot of time and money constantly turning over new equipment in pursuit of some "ultimate" audio experience. Hey, if you're got the time, money and motivation, then from my perspective, have at it - it's your time and your money as far as I'm concerned. But I'm just not one of those people who is looking to go out of my way to spend large amounts of time and money on audio. I'm thinking about it now because I am in the process of replacing components in a system that I have had for over a decade. |
Here is an equation that I found to estimate the resonant frequency of the cartridge cantilever:
rf-c=159/sqrt((eff_mass-t+mass-c+mass-f)*(compliance-c))
rf-c: resonant frequency of cartridge cantilever (Hz);
eff_mass-t: effective mass of tonearm (g) (11g for Triplanar);
mass-c: mass of cartridge (g);
mass-f: mass of fasteners to attach cartridge to tonearm (g) (I use 0.5g as a guess);
compliance-c: compliance of cartridge (10-6 cm/dyne).
As an example, I have a Lyra Delos cartridge so for me:
mass-c: 7.3g;
compliance-c: 12;
so I end up with rf-c=10.6 Hz.
I treat this as an estimate, but it is well within the 8-12 Hz range. |
Since it takes so little time (less than the duration of a cut on an LP), remove the trough and try a practical observation. It's pretty simple to do.
The trough is attached to an arm. The arm attaches to the tonearm by a screw that is not accessible from above. Whether it is easy to remove depends on the armboard. For some turntables, the removal is easy, for others not so. I'm in the latter category. I would have to remove the tonearm from the armboard to access the screw. But, yeah, if it's easy to remove, then it's probably worth a try on a "what the heck" basis. |
You are on the right track with this tonearm resonance issue. It is very much a result of the amount of energy a cart is allowed to impart back into the arm. This is not only a function of the compliance, but also the damping of the cartridge itself. Some cartridges are notorious for transferring relatively significant amounts of energy into the arm.
I'm not understanding the distinction that you are making between "compliance" and "damping". In fact, I'm not sure that I understand how you are modeling the system. I will tell you how I conceive the system model and then you can comment on where I might be incorrect or leaving out relevant information. The cantilever is attached to suspension within the body of the cartridge. That suspension can effectively be modeled as a spring. The total of the effective mass of the tonearm and the mass of the cartridge can be modeled as a mass that is attached to the spring. In a spring system, energy can get trapped within the spring when you excite the spring at a resonant frequency for the spring. That's what causes the spring to vibrate out of control. In the cartridge context, the excitation for the spring comes by way of the stylus. The source of the excitation is any energy source that couples through the stylus, this includes the groove of the record, vibrations from footsteps, etc. Under normal circumstances, the kinetic energy from the excitation is passed through to the attached mass (cartridge body and tonearm). Maybe this is what you are referring to by "damping", but that occurs outside of the cantilever. So, if you want to test the ability of the tonearm to dampen vibrations, you can do that test separately from the cantilever. That was the "tap" test that I described earlier - it was a test to see how well the tonearm could dampen vibrations. As Atmasphere stated, the Triplanar is made using vibration dampening material (I don't personally know that to be the fact, but it seems reasonable to me). In the case of a resonance in the cantilever, kinetic energy gets trapped in the cantilever suspension and the spring vibrates in an out of control fashion. At a resonance, significant amounts of kinetic energy are transferred to the tonearm. So now you have a situation where there is a lot of energy being transferred from the stylus (which is vibrating) to the cantilever and from the mass (cartridge/tonearm), which is also vibrating. So energy is being transferred into the cantilever (spring) from both ends. When the frequency of energy transfer is just right (i.e. at the resonant frequency) this creates an unstable condition called a resonance. This is the physical mechanism by which the resonance in the cartridge cantilever operates. A resonance that originates within the tonearm would be a different mechanism. I no reason to presume that such a resonance would, per force, trigger a resonance in the cartridge cantilever, but I would expect the cartridge to pick up the energy from this resonance. If the resonance is within the audible spectrum, I would expect that you would be able to hear it. Apparently some here believe that the Triplanar has such resonant properties. I don't know; I've told you the sum total of my testing on the matter. But for my part, I'm probably at least as interested in understanding how all this stuff works together than I am seeking the "ultimate" sonic experience. When I got my turntable system, my attitude about it was to get a system that I expected would sound pretty good (it was replacing a Technics SL-BD20D turntable that I had had for a decade). While I ended up with a turntable system that sounded pretty good to me, what I did not like about the process was the large number of unknowns. There are 5 components that work together in a turntable system: the turntable, the tonearm, the cartridge, the phono stage and the tonearm cable. There seems to be a belief that some turntables work better with certain tonearms. I could never get a good explanation as to how these determinations were made other than they were the result of trial and error. I have since gained a better understanding (through my own efforts) of the relationship between the tonearm and cartridge, and between the cartridge, tonearm cable and phono stage. I engage in discussion like this because my primary interest is understanding how stuff works and to that end, I've learned quite a bit in discussions like this. In some ways, you can learn more when you disagree with a person than when you agree. |
08-22-10: Dougdeacon
the publication of suggestion #6 here is what inspired Tri-Mai to add that small, threaded VTF weight. You apparently got one and your gratitude is duly noted!
The fact of the matter is that I do appreciate that you contributed to improving the tonearm. I only got my tonearm a couple of months ago, so I didn't know the history of it all. As to your other comment:
As for theoretical arguments that the damping trough is quite rigid and "shouldn't" need to be removed, I'll refer you to the dozens of owners who've actually tried it. Not one has failed to hear improvements such as I described.
Whether you choose to try it yourself or not is up to you of course, but theoretical objections won't convince anyone who's actually heard the difference.
I tried to make clear that it is not my business to tell people that they aren't hearing what they say they are hearing. My inquiry tends to focus on whether I can make sense of what other people are saying; things that make sense to me are more persuasive than things that don't make sense to me. I must say that the fact that other people say that they can "hear the difference" is not particularly persuasive because you always have to watch out for the "emperor's new clothes" phenomenon in which one person says something, and then other people possibly convincing themselves that it is true because they saw it in writing somewhere. The reason for my skepticism is that in this forum, I have read incorrect statements made by people who assert the authority of the statements on the basis that others had written the same thing, or that they saw it in a wikipedia entry, and so forth. While the Internet is a good source of information, one of the problems with the Internet is that incorrect information can get propagated, and then acquire a certain measure of authority by the mere fact that it was repeated. |
08-27-10: Thom_mackris
We can discuss issues of rigidity until we are all blue in the face. Would you say that the thin bar that supports the damping trough is more rigid than say, a ... tuning fork?
I won't speak about all tuning forks, but the tines of a fork have properties of a tuning fork. I would say that the trough on the Triplanar is more rigid than are the tines of the fork. However, you have to keep in mind that there are several factors that influence the resonant character of a tuning fork. Among those factors are the geometry of the object and the material properties of the object. I would encourage you to read the comment by Atmasphere:
08-23-10: Atmasphere
The Triplanar has a extensional damping material on the arm tube to reduce mid and high frequency resonance artifacts. This is one of the reasons this arm is so neutral- most arm manufacturers do little to address this issue.
This is an example of a statement that makes sense to me. To my observation, when I tap the Triplanar at various points, I found the tonearm to be very dead. I can believe that the material properties of the Triplanar dampen vibrations. So my empirical observations support what Atmasphere is saying. It is hard for me to imagine that such an apparently dead tonearm would be picking up the resonances that some here have claimed to be the case. You are correct, people can discuss this stuff until they are blue in the face, but ultimately what counts is whether a person knows what they are talking about. In my case, I tend to make that determination based on whether I can make sense of what the person is saying. |
Tapping on a Rega to find resonance points is one thing, tapping on a Triplanar is plain foolish and will not reveal the differences in nuance that these tips address. The vibrations created at the cartridge are entirely different from the vibrations you created by tapping on your arm. Your empirical observations are completely irrelevant to what happens in the cart/arm during playback. And let's not forget that the particular cart in use will have an impact on the vibrations the arm sees.
Heretofore, people have just thrown around the term "resonance" without saying exactly what they were talking about. It appears that you are citing a specific resonance: namely, the resonance in the cantilever of the cartridge. This is something that I can work with. From what I understand, concern about cantilever resonance is a legitimate concern. However, the way that you address that concern is to know what you are doing before you buy the cartridge. For example, it is not a true statement that the trough in the Triplanar is "vestigal"; if you use a low compliance cartridge with the Triplanar you can have problems with resonances in the cantilever. That was why the trough was put there - for use with low compliance cartridges; and there are companies (like Clearaudio) who still make low compliance cartridges. The thing to do, then, is to look at the specifications for the cartridge to determine where the resonance is likely to be if you install it on a Triplanar tonearm. As I understand it, you typically want the resonant frequency to fall in the 8-12 Hz range. Now, if there are other sources of resonances to which some here are referring, where the source or potential cause is not articulated, then I can't work with that. But what I do know, is that it appears to me that there is a fair amount of effort involved in removing the trough from the Triplanar. I don't know why I should undertake that effort other than for the fact that I read some comments from people who proclaim that it will make a difference and that, somehow, if I can't tell the difference then the fault lies in my hearing or in my system. I make no personal statement about anyone making such assertions, but the way that I think about things, it's hard for me to work with these kinds of claims if I don't understand the underlying physical phenomenon that I am trying to address. My training is in electrical engineering and not in the arts, so I think about this stuff differently. |
08-30-10: Dougdeacon
Dan,
Thank you for asking, I appreciate it. You'll find the answer in my last post, dated 08/27/10. I haven't posted since as it would be fatuous to contribute to a discussion after explicitly asking that it stop.
I've got to say that it seems a bit presumptuous for you to act as though you have personal ownership of this discussion. If you don't wish to comment, then you are free to independently decide to not comment. Anyone else can similarly make their own decisions (of course this is a moderated discussion, so the moderator has something to say about this as well). Nobody is right all the time and nobody has all the answers, and that goes for everyone and for you as well. Here, an issue got raised that you couldn't address; take this as an "emperor's new clothes" moment because while some people will accept your conclusions on some topic just because you expressed it, some people will challenge you to explain what facts support your conclusions. With regard to this discussion, you have provided some useful information about the Triplanar tone arm. Most of it seems reasonable, some of it seems questionable. Other people, including me, have added some information. I'm not going to declare that everything I write is correct, but if someone has persuasive facts to the contrary, then I want to see it; my attitude is that I might learn something. Even if I am inclined to disagree, it will likely force me to get my facts together to support my opinions; or I might get my facts together and find that they don't support my opinion. Either way, ego is of littel value to me here, the idea is to learn something, otherwise this forum is of little value to me. |
