@dover
the RS-A1 does indeed have a rotating headshell but what most people do not realize is that it is intended to have the pivot of the headshell directly above the stylus. Most people view this as a "horse and trailer design" with the pivot ahead of the stylus so it can better follow the groove. This is NOT the intent of the design. I have a fair amount of experience with this arm and find it to be a really good sounding easy to set up design. In trying to measure the tracking abilities the numbers were not representative of the perceived sonics. I also have a 9" Schröder Reference which I underhung and set of 0° offset and again the perceived sonics of the angular misalignment didn't seem anywhere near the same as a similar error on a traditional overhung tonearm. It is important to note that in both of the above cases the "design" of the underhung arm had the ability to absorb the energy caused by mistracking. The cartridge suspension allows for movement in the lateral and the vertical plane but conventional designs go to great lengths to lock everything else in place. The RS-A1 has the ability to rotate axially along the vertical plane and the Schröder has a floating magnetically damped bearing. I also believe the the the Viv arm also has this ability to allow some form of absorption / damping in a third direction. If we accept that angular error causes mistracking, it seems entirely plausible that how the arm deals with and recovers from a less than ideal situation could play a large role in the sonic signature of the design. Simply equating X° of angular error to some rumored distortion percent and calling the playing field level is far too simplistic of an approach.
dave
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@dover
They claim that the pivoted headshell deals with needle chatter.
I think this is exactly the point. I find the term "mistracking" quite vague and have yet to fine a "firm" definition of it. On the most basic level mistracking is any movement of the stylus that is not in the direction of the path made by the cutterhead. I do believe we are constantly mistracking and how the system deals with that behavior is critical to both the final sound and ultimate wear on a record over time. The net results of any mistracking are two fold; sonic degradation in the immediate and stylus/record wear in the long term.
Unfortunately this is not something that can be distilled down to the TAE being the "only number we have" so that is all that matters approach taken by some in this discussion. We first have to accept that for a given cartridge there is a distinct possibility that the sonic results of a 5° TAE will not be equivalent from tonearm to tonearm and I think that is the point that many who use and like the underhung arms are trying to make.
Is it possible to reverse the headshell 180 degrees with the RS and run a trailing pivoted headshell ?? Could be interesting.
Interestingly enough... I see two distinct problems with the concept of the RS-A1. Being able to align a stylus to a hidden uni-pivot bearing 17mm above it is a challenge and then only being given three pair of mounting holes at 6mm increments makes the concept of the pivot directly above the stylus a near impossibility. That said, when eyeballing it I have always picked the slots that error on trailing side since the thought of the stylus leading the pivot terrifies me. Of most importance the sound has never given me the feel that there was severe misalignment which lead me to much of my thinking above.
dave
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@mijostyn
Human ears make very poor measuring equipment and you do not know what you are missing. Ignorance is bliss.
Sadly, our ears are all we got. To go against our ’lying ears’ in the name of science shows lack of conviction in the ability to form and voice an opinion.
dave
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@rauliruegas
The issue of zeniyh is almost bs because we all know that if exist something imperfect in the whole anolog subject is exactly ANALOG and what surrounded it.
How can you say the above and then go on about TAE of the rigid float arm??? As Lew pointed out the tolerance specification from Orbray and Fgyger is ±5° and just because you choose to ignore it doesn't mean it is not a huge problem.
@mijostyn
Lew asked you if you paid attention to Zenith and you assured him you set the SRA with the nicest tools on the planet without answering his question about the zenith accuracy of your carts. You could send them to @wallytools and have JR take a look at it for you.
dave
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@mijostyn
A tonearm has to be held rigidly in all but two directions rotation vertically and rotation horizontally.
How does the Schröder Reference and anyone who is a fan of it fit into this world view?
dave
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@atmasphere
The problem with the 'mechanical engineering' view is when you define a "goal" or a "standard" then it can easily be seen if that goal is met and an unassailable judgement made. No consideration is given to the absolute magnitude or the underlying importance of the goal to begin with. As Lew pointed out above....if vanishingly low distortion is set as the goal then the system with the lowest distortion must always be best.
modulation on the LP itself will result in the arm not being perfectly in locus above the groove as it should be
what happens when the modulation is so extreme that it is actually considered mistracking? Is it at all possible that not being 100% rigidly coupled could cause the recovery from mistracking to be more benign? Now consider that mistracking is not an all or nothing type of proposition and is constantly happening and I seriously have to question the importance of the rigid coupling anyone demands. Everyone is allowed their choice of compromise and the choices by Viv Labs and the supporting anecdotal information is really interesting to me. Productive discussion about the factors involved is helpful to all and it seems at least plausible to me that the lack of rock solid coupling and anti-skate could make say 5° of tracking error on the Viv Labs more sonically benign than a lesser amount of TAE on a 'traditional arm'. One other thing that strikes me as odd in this all is that if TAE is truly the sole arbiter then why do the shorter underhung arms seem to be preferred?
dave
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@atmasphere
Agree 100% with you on the distortion which is why i tried to make a parallel with TAE. I find it highly unlikely that every tonearm cartridge combo will respond to TAE in the same manner and there is more to it than simply slapping a number on it and calling it equal. I think we can all agree that the lower the TAE the better but If we accept the belief that the lowest TAE is best then a 12" arm must better a 9" arm which is a statement that will draw lots of ire here. Going further a linear tracker would be better yet. With the new 9" sapphire arm, Kuzma counters this by saying arm rigidity is more important than TAE much in the way Viv labs asserts Skating forces dominate the situation. I see nothing technically inconsistent in any of the Viv labs assertions to merit calling them "stories" or deceptive in any way but it seems some here feel differently.
WRT cutting level and mistracking, it seems there is not a good definition of what mistracking actually is. My take is any movement in a direction not cut on the record is mistracking which means it is constant occurrence from numerous causes. I think the concept of "If it makes it across track 4 on record X it is a great tracker" is a far to simplistic all or nothing approach. The devil is in the details and lots of things come into play here and exploring the details is the best we can do.
If the coupling isn’t there as I have talked about, one of the results is more mistracking. IOW it works opposite of what you propose. This is simply because the arm is putting more energy into the cantilever.
Like distortion and TAE, mistracking cannot be a one size fits all proposition and making it thus is going in the wrong direction. What if it is the type of mistracking is what matters? I have found that comparing a conical to an advanced profile for a given angular error nets interesting results. For angles in the ±1° range the advanced profile is substantially better but once outside that range the conical becomes the preferred choice. IOW 5°≠5°
Regarding your last question, how do you know that underhung arms are actually preferred? Do you know of a poll regarding such??
Didn't mean to suggest that. I simply noted that amongst the specific subset of Viv Labs arms, the 9" arm seems preferred to the longer versions which is odd if TAE is the true metric of quality some make it. I do want to be clear that with my current setup (traditional offset overhung rigid bearing arm + advanced profile stylus), I find more than 1° TAE problematic but by comparison the same profile (microrisdge) on the underhung Schröder reference reminds me nothing of what I would expect hear from a similar error on a traditional arm. This simply tells me that there must be more to this than simply looking at the TAE as a single factor and explains my interest in this thread. Do I ultimately expect to become an underhung fanboy??? No... but that doesn't mean there isn't something to be learned from those who like it ~17mm short :-)
dave
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Lew,
It wouldn't be the first time logistics determined merit in audio. Everyone is allowed their preconceived ideas of what constitutes a good design. Universally extrapolating those beliefs and decrying anything that does not align with ones 'ideal du jour' serves little purpose. This is just another case of how much better my half empty cup of Evian is than your half full cup of tap water. If we don't accept the possibility that something outside our realm of experience might be better the chances of actually moving forward and learning are slim.
dave
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Lew,
the start of the response was to your point that many may use the 9" because it "fits" I'm with you on the scientific approach of observing behavior and then trying to explain it rather than using theory to dictate behavior.
@rauliruegas
Where are those evidences/facts/measurements?
When something fits the normal expected pattern of behavior all is well but in this case we have a fairly large break in that normal pattern of behavior when an arm with a nontraditional design establishes an observable pattern of people enjoying the results in spite of what most call an "obvious flaw" One camp here explains this by calling the manufacturer a charlatan and suggest the consumers are suckers who obviously have no clue about what constitutes good audio. They then proceed to parrot numbers and theories to support their opinions. The other camp here finds it interesting that he conflict exists and is intrigued to dig a bit deeper to see if there may be overlooked factors. If you pick any topic in audio a proper technical argument can be made for and against it but at the end of the day it is an established pattern of observed behavior that sets the direction everyone travels.
@pindac
Amen my brother!
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@atmasphere
The metric that needs to be discussed here is the lesser of the two evils which makes us wander into the land where ears become the ultimate arbiter. At that point individuals are allowed to have differing opinions and the vast majority here are respectful of others who have taken parallel paths.
Any offset is picked up by the cartridge as noise or coloration depending on the motion involved.
I see two possible situations here. Lets assume a 3° Zenith error at a given point on record. In the case of a traditional tonearm rigidly fixed in all but the lateral and vertical planes, the misalignment will cause a force in a direction that the tonearm is prevented from moving so it will need to be transferred to a direction that movement is possible which will come at some sonic penalty. Now consider the same situation with a tonearm that allows 'some' movement in a third direction. I'll agree that this will also add some sonic penalty as you describe but also see the possibility that it could be a much more benign penalty than in the first situation. Now take this a bit further to the extreme of a severely misaligned cartridge and we have the discussion at hand. The idea of mistracking reminds me of the mike tyson quote “Everyone has a plan until they get punched in the mouth.” Thinking you are going to have a setup that won't mistrack is akin to planning on getting into the ring and not getting hit.
I suspect the longer arm, like any other longer arm, suffers the issue of greater mass. You may well need a cartridge of lower compliance.
Oh boy.... there is another can of worms in audio that needs to be re-examined. I presume you are referring to the tonearm resonance. Everyone here should go ahead and add weight to the headshell to double the effective mass of their tonearm and see if their resonant frequency changes by the predicted factor of 1.4.
@rauliruegas
Do You think that an observer with good equilibrium objective/subjective can in any way trust on that even after " thousands of observations?, makes no sense at least to me.
Can you give me one "objective fact" in audio that is not firmly based on a solid foundation of subjective experiences?
dave
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@racedoc
The magnetic oil film helps to prevent any bouncing from the needle to start
resonances but as you know that oil is not compressible there is no floating at all.
Oil is not compressible but it will displace. Is there any movement in the arm in a direction beyond the lateral and vertical?
It has always been my thought that simply using TAE as the sole figure of merit in this comparison is flawed since there are many other aspects that can make a 5° TAE of a 'traditional' arm soincally different than the same error on the Viv.
Dave
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@maxson
Thanks for confirming. I suspect it is this additional ability for movement that plays a big part in the arms response to and recovery from movements that cause mistracking.
dave
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@lewm
Mijostyn’s position could be turned on its ear: you may be used to certain distortions created by overhung tonearms that you “like”.
you mean like skating forces causing the TAE to change dynamically with modulation levels?
I spent another week listening back and forth between the "straight underhung Schröder" and my traditional Schick and the normal cues to TAE that I key on are not the same in both cases. Gross TAE on the schick results in a harness to the high velocity peaks (think miles' muted horn) and that "harsh" sound is substantially less with greater TAE on the straight arm. The other interesting difference is the larger that normal TAE on the straight arm seems to come at the cost of an overall higher noise floor. This isn't immediately noticed until I return to the eerily black background of a properly aligned cartridge on the schick. That said I am beginning to think that there is a reasonably good chance that since very few people are aligned anywhere near where they think they are, the nature of the Viv labs is akin to a conical vs. an advanced profile. Incorrectly set up the conical wins.... properly set up the advanced profile takes over the lead by a large margin. A 2° change in TAE has changed one of the best cartridges I have heard to one of the worst. Change the microridge profile to a conical and suddenly you are "pretty good" for both setups.
dave
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All of the offset is applied at the single mount screw. The only thing preventing a 0° offset is the back of the cartridge hitting the armwand. I made a shim to get the clearance so the cartridge could be set straight.
I looked at the math and suspect the best setup for this type of arm puts the single null point about 80% of the way into the record. I have found that the predicted distortions by the math need another factor of 2 added beyond the traditional weighting to match what I hear. I also suspect stevenson was on the right track since things get really ugly as you pass the second null and approach the lead-out groove.
dave
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@lewm
My best guess is for some reason the underhung arms handle the TAE differently than a traditional arm. I think i would liken the sound to that of the conical vs advanced profiles. In all but the best setups the conical will sound better but leave a lot of the music in the groove. If you want a quick simple setup that will sound good use a conical and an underhung arm. If you have the ability / time to nail the setup an advanced profile on an offset arm will be better. For some reason in spite of all of its problems, the RS-A1 can get plopped down and be playing music in 5 minutes at a level of a fairly well set up traditional arm.
@maxson
I am about 12mm and I would listen to the last track as a test for alignment. For the last third of the record the single null moves about 3mm toward the spindle for every reduction of overhang of 1mm. Zenith also plays a role here and the chances of actually getting it to 0° is slim so this will change the theoretical ideal. I suggest starting with coarse moves and the last two tracks of a side since thats where the gross errors are most apparent. I do want to note that unlike the three underhung arms discussed here, the arm you are going to try this on is rigidly coupled in all but the lateral and vertical planes so i would be very interested in your results.
At the risk of giving all of the naysayers here some ammunition I believe this is what the math says about the resultant distortion of an overhung and underhung setup. It is this huge disconnect between what the math says and what people hear that has me interested in this topic.
dave
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Math without an attachment to a subjective listening experience is only worth the computer screen it is displayed on. Your Rorschach reference is a perfect one for this situation and you seem to be the therapist explaining to the patent what they should be seeing based on some measured metric.
dave
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Ahh like the old Vace-Fase illusion you get a 50-50 shot at getting correct. I did a google image search and got about 3 images into an online test and it was funny how you would look at the image and then tick a checkbox from a list of possibilities on the next page. Ya gotta like the power of suggestion to make you see / hear things.
dave
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@dover
I am suggesting keeping the headshell offset at 0 ( straight ) move the arm mounting point forward in order to set 2 null points.
The combo of properly set offset + overhang is the only way to get the 2 null points. If you eliminate either one of those aspects you can only achieve a single null. This single null still requires proper setup to achieve it.
My gut feel is that the straight headshell has more impact than the "underhung" geometry.
I am starting to believe the effects skating force are painted with much too wide of a brush. One only needs to set a traditional arm with no antiskate on a blank record and note the speed at which it flies to the center. Now take an underhung arm without offset on the same record and in theory the skating forces should identify the location of the single null. This will not be immediate and will take several seconds. The thing that is interesting about this is while both setups do have skating forces involved, the magnitudes of the two are vastly different. One could argue that the application of 'proper' antiskate to an offset arm will result in forces similar to that of the underhung arm but then we have to consider how modulation level comes into play and the need for a big brush to cover up the reality hiding in the cracks becomes clear.
dave
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@rauliruegas
Null points calculation it not depends of any other parameter, not even tonearm EL.
Whaaaa???
you need to specify at least four parameters which typically are alignment type, inner groove diameter, outer groove And Pivot to spindle (P2S). The math then returns you two null points, effective length (EL) and offset angle. The overhang (OH) is then found by subtracting P2S from EL. The knowns and unknowns can be reworked based on the information available. Effective length can be substituted with a known overhang and the P2S returned.
dave
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@rauliruegas
specifying a formula and not understanding its relationship to the discussion at hand serves little good. I doubt Løfgren would suggest it possible to get two null points without the addition of overhang no matter how much you point him to his math.
dave
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@rauliruegas
You have stripped all context from my original quote which was about the requirement of both overhang and offset to get two null points. Without overhang which requires an effective length to calculate the two null points cannot exist.
dave
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@rauliruegas
for some reason you introduced this particular tangent in response to me simply mentioning in order to get two null points both overhang and offset are required.
In this thread on feb 14 you wrote:
Anyway, for me the VIV/underhung issue is exhausted and at least for me useless to follow.
yet you still are active providing a distraction to the topic at hand. Next can we expect you to explain how the circumference of a circle divided by 2X its radius will always equal 3.1415? It does not matter what the diameter is, it can be 10mm or 32 miles, Pi will be the answer.
dave
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@rauliruegas
then please kindly explain to @dover how to use the null point formula you presented to set the two null points for the arm with zero offset.
dave
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@rauliruegas
As any can see it needed only most inner/outer groove radius and nothing else.
This will give you the theoretical placement of the null points. Nobody is debating this. Again the topic at hand is actually placing those null points on a record surface and being able to trace through to them with a cartridge.
More specifically the only comment by me on this topic was simply to state that in order to get existence of two null points, both overhang and offset are required. In order to calculate those a third variable must be called out (EL, O or P2S). Using only part of a complete set of formulae "to prove one is right" is of no use in this case. This has truly become a classic example of what @clearthink outlined above and apologies to all for engaging in this fray of the thread.
dave
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@maxson
The less the underhang the closer the single null point will be to the runout groove. It is also important to pay attention to the cartridge zenith since a slight offset of the Zenith from 0° will have the same net effect as a slight change in the underhang.
dave
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Hey Lew.... Great job!
Have you seen any mention in the documentation on where they want the null point to be placed? My guess is 2/3 to 3/4 the way to the leadout is a good start.
dave
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please check.
if you can trust the math it seems that putting the null at around 72-75mm will net the best overall compromise. Below is what 72mm looks like compared ot 99mm and a typical Lofgren A.
dave
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Hey Lew,
This arm is a paradox. It clearly does not appear to have the same 'weighting' for TAE as a conventional pivoted tonearm. Mijo mentions above that there is skating in all non-linear trackers but I think it needs to be clear that the nature and magnitude of the skating on a traditional arm is much greater than that of its underhung brethren. I mentioned earlier in the thread that when I placed an underhung arm on a blank record surface it pretty much stayed where I put it with no anti-skate dialed in.
When we get to a situation like this where experience conflicts with traditional beliefs I always tend to side with the experience and then look for the unique details of the specific situation to try to better hone my views on the traditional. In an underhung arm the single null point can be manipulated by either changing the amount of the underhang OR changing the zenith. My gut feel is to set the zenith to keep any skating to a minimum then adjust the underhang to set the null.
dave
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Maybe this indicates that zero tracking angle error is not the Holy Grail some claim it to be.
That's the designer's whole point, right?
I suspect there are a few other things at play here beyond the TAE vs. skating force. From personal experience I can say that 3° TAE error on a conventional overhung setup is vastly different in sonic character than the same error on the 9" Schröder reference I set up as a 0 offset underhung arm. I purposely chose 3° TAE since it is beyond properly setup traditional tonearm error but guaranteed to occur on any underhung design.
dave
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" “From the shape and location of the curves, it results that the largest distortion risk occurs when the overhang is not correctly set for the linear offset. On the other hand, the angular offset itself is not so critical”
I don't think when Löfgren had the above idea that he considered the concept of an advanced profile and the possibility of dissimilar info on opposing groove walls. I think those two additions make the correct angular offset (Zenith) as or more important than overhang.
dave
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@rauliruegas
Well, something to share with you is that I just finished my listening tests making on purpose a 2mm overhang error and other test changing only ( what more or less permits the headshell ) the angular offset. I think you need to do it.
If you only change overhang without a corresponding change in Zenith you will not be in a good place. Here is a standard Lofgren A compared to a Lofgren A with a 2mm increase of overhang.
here is the same +2mm with a complimentary 1.4° change in zenith.
and to complete things here is back to the standard Lof A overhang with a 1.4° Zenith error.
dave
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The fact that the Viv arm sounds good to some people speaks to the lack of sensitivity our ears have to the distortion created by zenith error. It is well made and trick which helps.
@mijostyn While your supposition above seems plausible, I would not consider it a valid statement of fact. I'll agree that a no offset underhung arm has much larger TAE than a traditional offset arm. I'll also agree that many find this type of arm to sound good. To attach these two facts together to make conclusions about the relative audibility of Zenith error is counterproductive and a much deeper dive into what is going on is needed. I know I have done similar in stating that a 3° zenith error in an underhung arm (the one case i tried) did not seem to equate sonically to the same error in in an conventional arm. It has also been posed that the UH arm users simply like distortion, that TAE is a pleasing distortion, and that if you like the sound of this arm your system is not capable of the required resolution for high end audio. It can also be pointed out that if our ears are not sensitive to TAE then any discussion of different alignment types becomes a fools errand.
I find all of this to be the exact opposite of the proper scientific method where one observes a pattern of behavior (good sound from the UH arm in this case) and then goes in search of an explanation. Many here seem to be looking at the 'standard' procedure of judging setups by some theoretical Y-axis value on a graph and cannot deal with the concept that there may be much more to this than looking at an excel spreadsheet. The differences in anti-skate between the two methods as well as other tonearm build factors have also come into the discussion. I expect it is some complex relationship of all of the factors mentioned in this thread that explains the seeming disconnect between TAE and the sonic perception of a 'traditional' vs. Viv arm.
I have been joking lately that crosstalk and channel separation have become the most important parameters in cartridge setup simply because they are the easiest for anyone to measure and brag about. I am adding the whole discussion of alignment types and TAE to this category since they are really easy to calculate and very difficult to implement to the accuracy required.
dave
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@mijostyn
How do you know you actually have the alignment you say you do? Here is a test report of three random samples of stylus assemblies from an order I placed. This is representative of the best numbers I have seen thus far and are kind of terrifying.
I don't care how great of a protractor you have if you are aligning to a cantilever without consideration of possible diamond set error then I see the baby going out with the bathwater. JR addresses this by optically placing a number on the Zenith error and then providing a protractor with the ability to correct for this error. Next we can open the can of static vs. dynamic worms and observe how much skating forces and groove modulation come into play here as well. In many setups, when you adjust azimuth to better crosstalk numbers you also change your alignment. Add or remove a gram of anti-skate correction and you have just changed your alignment. Its really easy to brag about a preferred alignment and the precision of your setup and quite humbling to realize you are actually nowhere near where you thought you were.
dave
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Hey all,
Another problem I am having with this discussion is the term 'distrotion' is being used way too generically. I believe that the original use of the term by Löfgren etal was referring to THD caused by having a HMA (horizontal modulating angle) different than the HTA (horizontal tracing angle). In his AES convention paper, Richard Tollerton digitally simulates errors of VTA and HTA in reproduced music and concludes large errors (beyond what an underhung arm provides) are required to enter the realm of audibility. This is in direct contrast to my experiences and as far as I can tell Tollerton only considers the effect of the relation of the cantilever in the horizontal and vertical planes and like the pioneering work does not include the effects of incorrect SRA or Zenith.
I find vinyl playback to be an inherently high measured distortion medium and any numbers predicted by the various alignment types tend to be of such a small comparative magnitude that much of this discussion is about the mouse and not the elephant it has trapped in the corner.
dave
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the elephant is every other thing about vinyl playback that obscures the ability to measure minor changes in THD as a result of TAE. Attempting to assign an accurate and consistent FOM to TAE from THD has thus far proven to be an effort in futility. An interesting addendum to this is how many people take the theoretical numbers rooted in the conceptual world and argue about the superiority of one alignment vs. another without a clue as to how their cartridge is actually aligned in the real world. I think it can be summed up with my belief that if you have two null points on the record face then you have won and bet far greater than half of the folks out there do not have any null points. For reference, based on the goal of an ideal Löfgren A a TAE of ±0.8° will push the null points off the playable area of a record.
dave
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