Discuss The Viv Lab Rigid Arm


I am trying to do my due diligence about this arm. I am just having a hard time getting my head around this idea of zero overhang and no offset. Does this arm really work the way it is reported to do?

neonknight

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.

You expect trouble when designed analog equipment! It is for that reason- vibration (whether from the LP, airborne or otherwise) that you want the rigid coupling I mentioned, as well as preventing any play in the arm bearings or platter bearings- otherwise that play will result in the arm not being where its supposed to be: directly over the cartridge.

The rigid coupling, ie, Tonearm and Chassis rigidly fastened and connected via precise Geometry, using a coupling material that has exceptional damping / dissipation property is very advantageous.

To have a Platter and Tonearm interfaced and functioning with the tightest mechanical tolerances in place for the critical interfaces and offering a friction free operation is also very advantageous.

Combine the above two advantageous conditions together and the outcome is a mechanical interface that is close to being absolute in optimisation for the function. 

When the advantageous conditions are present, it enables other concerns to be considered, of which some are taken quite serious and others not too much.

Concerns such as:

Is the Mounting of the Assembly fit for the role, where minimal environmental impacts are controled to the point of not being detrimental.

Is the Eccentricity of the LP able to produce Wow that has a detectable presence and is a detriment to the signal being produced, as the result.

Then there are the micro issues, such as the impact of drag.

Is the Wow able to cause friction/drag, that is detrimental to the signal produced. .

Is the styli not being at the same height/plane as the Vertical Pivot Bearings Axis, able to produce drag/friction that is detrimental to the signal produced.

Is the condition of the styli, (not ultra polished) able to introduce friction/drag, to the point it is able to impact on the function of the armature and even worse tonearm, producing a condition that is detrimental to the signal .      

Mijostyn, You wrote, "You have to be kidding me Lew. After all I have said about measurement microphones, digital signal processing, and crazy microscopes? I measure everything that affects the performance of my system. If you don’t you are out to sea without a compass." And then in a later post you intimated I must be getting senile because I "forgot" you own the above gear. I forgot nothing; none of that stuff is useful for measuring IM or Harmonic or other kinds of distortion, which is what I specified in my prior statement. What you measure is frequency response curves (or rather your hoping for a flat line). All I am saying is that you (and me too) don’t really know how our gear is performing in our home systems, with regard to that kind of analysis of distortion in the electrical sense of the word.

Earlier also you fretted that the TAE created with an underhung tonearm will cause phase anomalies. What about the phase anomalies you and I happily live with, caused by dipole speakers where the rear radiation is 180 degrees out of phase with the front? What about phase anomalies possibly generated by the very steep slope hi- and low pass filters you told me you use at the crossover point between your subwoofers and your Sound Lab panels? (I believe you mentioned 80db/octave, done in the digital domain.) And finally, phase differences between the two channels, one vs the other, such as that theoretically caused by high TAE in a tonearm, ought to be much less audible or troublesome to the listener, compared to  phase anomalies within one channel, because the content of the L vs the R channel signals is always different anyway. The brain is taking in two complementary but distinct sonic signatures and melding them into a stereo image. This is also not to mention that studio recordings were seldom done in such a way as to preserve phase, top to bottom, anyway. So I would blow off phase anomalies as a major "problem" arising from TAE.

One of the Viv owners who commented in this thread, pointed out that the base of the tonearm is drilled out such that it can in fact be anchored to a plinth. Even if one doesn’t use those mounting points, the Viv sits on an arm board which is part of the plinth and is at least tenuously moving in unison with any perturbation to the bearing/spindle/platter assembly. So, worst case scenario, the coupling would be superior to using an outboard arm pod. (No offense meant to anyone who uses an outboard pod; I sure don’t want to open that can of worms again.) If it were me, I would bolt the base to the arm board and forgeddaboudit.

@lewm , you did not check out those programs. I can measure distortion both IM and harmonic. I usually do not do that as it is a PITA. I trust in the specifications of the equipment I buy. Distortion also is not something I can adjust aside from optimum set up whereas frequency response and group delays I can to great effect. 

Yes, we live with some phase distortion. The point is to minimize it. I used fairly potent sound absorption behind the speakers from floor to ceiling. The Sound Labs being the dipole line arrays they are minimize reflected sound otherwise to a degree impossible with any other speaker type including horns.

The Viv arm's bearing is floating which makes it worse than a unipivot which is pretty bad. 

The digital filters I use do not change phase. They will ring if you get carried away with the slope.

I have done the experiment of twisting the cartridge and underhanging it. The image is distorted and the blackness between instruments and voices disappears filled in by high frequency hash. Things like cymbals and triangles become harder to localize.

The Viv arm is a very poor design perpetrated by people who have no idea what they are doing. If I prevent one person from getting one I have done humanity a service. 

If the Viv bearing is “floating“ as you say, I would not like it either. I mentioned this very early on in this thread. Their literature is unclear. Can one of the owners and users of the Viv tonearm comment about whether the pivot point is fixed in space and not floating and also not a Uni pivot? That would be helpful to me anyway. but the main subject of our discussion has been underhung tonearms in general versus overhung tonearms, and the effect of TAE on sound quality. 

@intactaudio  : " on a solid foundation " but your observations on the VIV owners has not that " solid foundation ".

 

Observation must be under control with very specifics targets to look for.

First observation on the VIV is the manufacturer site that's a " bs " for say the least.

 

R.

What about the phase anomalies you and I happily live with, caused by dipole speakers where the rear radiation is 180 degrees out of phase with the front?

@lewm @mijostyn The reason any speaker with rear firing information should be at least 5 feet from the wall behind it has to do with how the ear processes near term reflections. When 5 feet from the wall behind the speaker the delay time is about 10ms. When the ear hears a sound, it makes a short term copy and looks for other examples in near term. If less than 10ms or so, the ear interprets similar examples as harshness (which is why side wall reflections have to be tamed), but if 10ms and over the ear can use it as echo location information, which means the sound stage of such speakers can be more palpable.

So I'd be unconcerned about 'phase anomalies' in this regard. 

@atmasphere With diffusion panels directly behind the speaker is it possible to shorten that 5 foot distance by a small amount? I have always considered trying planars but my listening room is moderate in size. 22'L x 16' W x 8'H. The most useful set up would only allow pull the speakers 3.5 to 4 feet off the front wall. Wonder if that is a viable option?

Dear @atmasphere  : Analog/audio is full of anomalies and the @mijostyn  pointed out: " The point is to minimize it. "  even what I " preach " in the forums almost always: put at minimum any kind of " distortions ".

But subjectivity makes that some audiophiles instead to put at minimumm those " anomalies/distortions " just added more, VIV confirm it.

 

Anyway, for me the VIV/underhung issue is exhausted and at least for me useless to follow.

To each his own.

R.

 With diffusion panels directly behind the speaker is it possible to shorten that 5 foot distance by a small amount?

@neonknight No. But if the speakers are closer than the 5 feet having something absorptive might help with the harshness that will result.

@neonknight , My system is on a 16 foot wall. Go look at it. The speakers are just over three feet from the wall and behind them the wall is covered from floor to ceiling with 4" acoustic foam tile. This greatly attenuates frequencies above 250 Hz which alleviates the harshness atmasphere mentions. This distance keeps interference out of the midbass and I use subwoofers below 100 Hz with very steep slopes. Without subs and wall treatment Atma-Sphere is correct. 

I have been using dipole panels exclusively since 1978. They have run the gamut from Acoustats, to Magnepans, to Apogees, back to Acoustats and now Sound Labs. 

Let me know what speakers you plan on getting and we can talk about it. 16 feet is plenty.

The "bearing" of the ViV is not a "floating" one in the typical sense.

 

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.

 

The most fascinating fact of the ViV is that it teases out the very best of EVERY

cartridge me and my friends mounted on it. No matter of weight and compliance.

 

But for sure the people here which never had an hand on this great tonearme

are bashing it because it not pays attention to "regulations and facts" and for them

 

...  the earth is still flat! ;-)

 

 

 

But for sure the people here which never had an hand on this great tonearme are bashing it because it not pays attention to "regulations and facts" and for them... the earth is still flat! ;-)

There are some people here who enjoy making grand proclamations and pronouncements. Many take a rather odd pride in this behavior, some peppering their remarks with comments such as, "I’m not polite," "I’m not politically correct" or my favorite: "I’m brutally honest" when what they really mean is, "I enjoy being brutal." They’ll often bolster their comments by claiming certain professional qualifications. Some have established YouTube channels they promote in hopes to monetize their "expertise." One of the logic-challenged ones you’re arguing with here claims to be a physician.

What these sorts have in common, as you note, is a lack of experience. Their hubris has convinced them that their intellect can overcome that deficiency and, to an extent, they are right: Knowledge and wisdom can help you avoid mistakes that otherwise would teach you the lessons of experience. But the truth they don’t want to acknowledge is v-e-r-y simple:

There is no substitute for experience.

That’s why I’ve avoided commenting on this arm. I understand as well as anyone here its unusual geometry and the measurable distortion that can result, but I won’t discount the reports of those who’ve actually seen and heard it. Without actually correlating expectations with actual results, the Viv’s critics have added nothing of value to this conversation. But their "contributions" make them feel very important, and that feeling is what they seek. It’s why they’re here.

Post removed 

Your motivations in general are worthy, but your judgement of what is a scam and what is merely an alternative approach that has merits and demerits is poor in this instance, because your mind is closed. And by the way, your argumens against underhung tonearms, leaving aside the specifics of the Viv, are mostly about Euclidean geometry, not Newtonian physics.

mijostyn

Cleeds would be talking about me.

As a frustrated intellectual he is unable to discuss the relevant issues regarding this arm as he is unable to understand them. He is also unaware of and unable to understand my real motive

Ad hominem argument - the laziest of logical fallacies. You’re not fooling anyone here.

@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

 

 

What Dave just said about TAE, and what I was trying to say early on in this thread.

All I know is that the RS LABS RSA1 tonearm violates every “commandment” of modern design:

underhung

not firmly anchored to plinth

cartridge DEcoupled from arm wand

unipivot

pivot is elevated above both cartridge and counterweight

CW dangles in space, free to swing due to LP eccentricity

And yet it works. By comparison, the Viv makes much more overall sense. Raul makes a fair point about the Viv website. There are many questionable claims on that website. You should see the RS labs owners manual. It is laughable. But that does not have anything to do with the results.

 

lewm

All I know is that the RS LABS RSA1 tonearm violates every “commandment” of modern design ... And yet it works. By comparison, the Viv makes much more overall sense.

Crazy, isn't it? I think there are actually many examples of things in audio that at first glance (or even second, or third glances) wouldn't seem to work. I find it incredible the fidelity we can get from an LP today. I understand the mathematic fundamentals behind digital audio, for example (Fourier, Shannon/Nyquist), yet intuitively it still seems impossible to me.

What interests me about these underhung arms is exactly that - the geometry is contrary to what we've all "learned' is best practice, yet reports from those who've heard it are very favorable. That's worthy of further investigation because it suggests there's something in the current set of accepted best design practices that's either being overlooked, or over- or undervalued. Identifying those underlying factors could lead to better pickup arm designs of every kind, including conventional pivoted overhung arms.

There are people who lack a natural curiosity about the way the world works. For them, there is security and safety in books and policies and theories. But real discoveries - by which I mean both the great ones that change mankind and the small ones that can yield the greatest joy - are usually found in the real world through experience.

I understand the mathematic fundamentals behind digital audio, for example (Fourier, Shannon/Nyquist), yet intuitively it still seems impossible to me.

Like any technology digital had an uphill path to follow. For example jitter was a thing known to cause problems... I have a transport from the early 1990s  (Teac) that was highly respected at the time. But over time its pretty obvious its gone out of date. People update them with better clocks. The newer clock boards you can get on eBay for $20.00 have two orders of magnitude greater frequency stability; after installation this aged transport sounds a lot better...

Some people are dumbfounded by how 'dragging a rock thru a groove' could possibly work; not really realizing that their old saw isn't describing what's happening, because:

There is no substitute for experience.

This is correct.

Its also helpful to know what people have experienced prior to making blanket statements about them. Is mechanical design experience helpful? Is the experience of learning from your mistakes helpful? Is the experience of connecting what measurements we can make with what we hear helpful?

 

 

 

... Is the experience of connecting what measurements we can make with what we hear helpful?

Exactly, and that has been my point in this thread. To make real progress, we need to correlate measurements with what we hear. I think that should be true in all aspects of audio equipment design - not just pickup arms. Obviously others are willing to dispense with the listening part.

Exactly, and that has been my point in this thread. To make real progress, we need to correlate measurements with what we hear.

@cleeds Its been my experience that's what you do to sort out what's going on.

That is what led me to increasing rigidity in the plinth of our turntable; increasing coupling between arm and platter surface and overall making it dead as possible- damped platter, damped plinth. As I did these things the impervious nature of the system began to emerge; when I started the system was sensitive to volume pressures of 90dB; after I was done even at 105dB it was measurably and audibly superior. 

My technique was to place the stylus on the platter pad and measure the phono preamp output while playing a 100Hz tone thru the line stage of the preamp, amps and speakers. 'Success' was in reducing the output. I found that the better the coupling, the more dead the system, the lower the output at any frequency accompanied by a perceived improvement in bass, mids and highs- the system sounded less congested.

Damping the platter was easy but the plinth got tricky since it had to be machined out of solid aluminum.

I've been trying to correlate amplifier distortion vs how the amplifier 'sounds' for a very long time. My experience with that is both the measurement guys and those that prefer to only trust their ears hate what I've been finding. I think this is because the work messes with their world view. Its not surprising to find some pushback on this thread on the same account.

 

Lew and Dave: The Viv armtube can slide back and forth in the direction of its length through the housing by about 1mm. It can rotate around the axis of the tube a few degrees and it can be lifted a couple of mm to the top of the housing, tho here it takes some lifting to oppose the magnetic force of the fluid--not likely to happen during play.

@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

 

Maxson, First, thanks for your response. To your direct observation, does azimuth remain stable over the course of traversing an LP during play? The top surface of the headshell on a Well Tempered Reference tonearm, for example, visibly rolls over toward the spindle as it moves from outer to inner grooves.

@lewm I've never seen the arm roll as you describe. It takes a bit of twisting on my part to get it to leave its upright position.

I did spend some time trying to see if it could be bought from a seller in Japan. So far no luck in finding a web presence for one who has it listed. 

Why do you suggest that “something happened” to the Viv with CF arm wand? So far as I know, it’s still available, CF being an option vs the standard metal wand.

Because I don’t see the CB on their website so I assumed discontinued:

http://www.vivaudiolab.com/Rigid_Float.html

Like VPI, generally seems that when both are offered, Carbon fiber tonearms performs better than aluminum/metal.  So I was wondering which ViV tonearm was better - the HA or CB?

 

DS Exports may no longer be involved.

Here in the US, it’s Mike Fajen @ Sierra Sound: 

 

For me, CF does not necessarily outperform stainless or aluminum or some other metal for use as an arm wand. I’d have to hear both versions. In general I have not been fond of CF in audio, except as headshell material. I do not care for the few CF tonearms I’ve heard, e.g., the Well Tempered.

@boothroyd 

thanks for the Sierra lead.  I’ll reach out to ask sonic difference between the HA and CB.  I haven’t found comparisons online yet.

The distortion created by the Viv's design, tracking angle in particular, are easy to measure. The fact that it and other designs that seem implausible are capable of sounding "OK" to some people means absolutely nothing in the greater sense, just as some obviously silly "tweaks" seem to sound better to some people. Human ears do not make very good measuring devices and what "sounds good" is a matter of experience which is varied to say the least. Since it is impossible to standardize our hearing and the systems we listen to we are all thrown into a washing machine of varied opinions much of them based more on individual bias than real substance. 

As for what sounds better, an aluminum or carbon fiber arm tube, properly designed they both sound exactly the same, like nothing. If an armwand has a sound it is defective. The arm wand that has no sound will always be more accurate. The ideal arm wand is infinitely stiff and totally resonance free. It has to have a mass appropriate for the cartridge being used. The Kuzma 4 point arm is a great aluminum design and the Sat arm a great carbon design. I have heard both and I do not think I could tell the difference in an AB test. I also doubt they are measurably different. But there are people who wax poetic over the SAT arm which admittedly is a beautifully made device. It is beautifully made like a Patek Philippe watch. My Garmin watch is not near so beautifully made and costs 1/50th what a Patek Philippe does but it actually is more accurate and a lot more informative.  How a well designed carbon fiber or aluminum arm tube functions depends on what it is attached to. 

@cleeds I am mortally wounded. I shall never be able to show my face in public again.  

 

On the comparison between CB and HA, from Roy Gregory's review on theaudiobeat with reference to "Carmen Fantaisie" [Decca SXL 2197]:

"If we return once again to the Ricci recording to furnish our examples, the RF7 HA delivers the same, frictionless passage through the recording -- indeed, to an almost greater and certainly more obvious extent. Its dynamics are more explicit and contrasts more vivid, with music sounding faster, more energetic and performances more vital. But that added speed, drama and expressive intent come at the cost of a less poised and leaner presentation. The aluminum ‘arm lacks the rich tonality and smoothly motive substance of the RF7 CB, instead offering angular elbows and attitude. With the RF7 HA at the helm, Ricci’s playing takes on a more aggressive and higher-risk quality, the metaphorical tires on this sports car starting to squeal and occasionally smoke. It’s exciting, it’s exhilarating and occasionally it’s uncomfortable. It’s also exactly the performance that I remember so vividly from my first listening sessions."

Mijo, I get what you’re trying to say about the “sound” of a tonearm, but what’s your reference for sounding like “nothing”? Every arm is made of something. How can something sound like nothing?

I keep thinking of George Costanza explaining to NBC execs that “Seinfeld” was about “nothing”.

Dear @mijostyn : " . Since it is impossible to standardize our hearing and the systems we listen to we are all thrown into a washing machine of varied opinions much of them based more on individual bias than real substance. "

You are rigth and the " problem " is that to each one of us like different kind and level of developed room/system distortions. The owners of tonearms as the VV one just like the developed distortions that are the " holly grail " for its ears/brain. Are these gentlemans wrong? certainly not because it’s what they like.

I already posted several times in different threads that no one can be questioning any single full subjective opinion, is untouchable even if for some of us could be wrong that opinion.. That’s the real problem with subjectivity but such is the audio world.

Btw, each one of us has " different " level of common sense due that our first hand experiences and ignorance levels/knowledge levels are different too as is each one of us: true " open mind " or true " closed mind ".

 

" properly designed they both sound exactly the same, like nothing. If an armwand has a sound it is defective. "

 

In theory I agree because not only the tonearm arm wand has to has no " sound " at all but all tonearm but it’s almost imposible to achieve in audio real world playback tests. In some ways " colorations " ( by many reasons ) are developed in diffrent ways and those colorations are what we listen.

 

R.

 

 

Raul, I advise you to listen to an underhung tonearm and consider that a mathematical solution to minimize TAE at all costs put forward in 1940 might not be the last word in 2023. That’s what I intend to do before forming a definitive opinion. Based on the RS LABS, I think you’re rushing to judgement. Also realize that your and Mijostyn’s position could be turned on its ear: you may be used to certain distortions created by overhung tonearms that you “like”. 

@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

How did you create an underhung Schroeder? Does it have zero headshell offset too?

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

 

 

 

Do you detect a greater uniformity of any colorations, from lead in to lead out grooves?  That's what I thought I heard with the RS Labs, less in degree and fewer variations in sonic character, compared to a typical overhung tonearm, as it traverses an LP.  Which made it sound more like a good R2R playback.  (That's my best metaphor for it.) This effect was not probably as great as may come across in my writing about it, due to the fact that we must use words to describe it.

I could probably underhang my Sperling arm---like the Shroeder, it just has a bolt at the headshell to set offset angle. How large is your underhang with the Schroeder, Dave? With the RS Labs it was between 5 and 10mm.

@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

@intactaudio Dave good to see the inquisitiveness ( the quality of wanting to discover as much as you can about things), is proving to be availing.

I was off this thread, but my visit and your last post has got me 'back in the game'.

As said, I have been fortunate in having it agreed a New Tonearm Design, I am being asked to be present for a demonstration and offer a assessment of the demonstration experience, has been agreed to have one of the models set up as a Underhung Geometry.

It will be a rigidly coupled Mounting, it will be used in comparison to the 9" and 12" Overhung Geometry. The length of the Arm to be allocated for a Underhung Geometry is yet to be made known.

The Plinth/Chassis will be able to mount Two Tonearms to a 12" length.

The demonstration is to use a Two Cart's, same Brand/Model with very similar hours of usage.

The Tonearm Design also has a Geometry, that has the Styli when in the Groove at the same height as the Vertical Bearings Axis Pivot Point.

Your taking the time to create the experience and evaluate, has been a added boost to my intentions. I am keen to see what is able to be created and where the attraction of the Geometry can be discovered, in relation to the Overhung alternative.

As per usual, whether Overhung or Underhung, all assessments will end up as a subjective evaluation, that is to be made through drawing from multiple years of experiences of being demonstrated multiple differing HiFi related Designs being put to use. 

There is a Computer Programme available occasionally for System Health Checks, especially for a Vinyl Set Up. The use of this on a well known system produced a end result, where the improvement in the presentation was by myself perceived as almost Tangible. The imaging become very focused and the performers were more present than what was remembered. This Software might? be available for the demonstration day as well. 

It will be used at some point to give the New Tonearm Design the fairest of lore, as getting the Cart' optimised in its set up Geometry will go a long way to help learn as much as can be offered.

      

Pindac, I’m sure you know this, but because you did not mention it, I hope your underhung tonearm will be built with zero headshell offset angle.

Dave, in your aural experience reported above were you listening to an RS-A1, or what? Also, what is “arbitrary distortion”? Could it also be called “subjective distortion “? Thx.

@lewm, "nothing" is the ideal goal. The tonearm's job is to hold the cartridge rigidly in the right position to do it's job having only two degrees of motion, vertical and horizontal. The right position is tangent to the groove with a SRA of 92 degrees and a stylus azimuth perfectly perpendicular to the surface of the record. The tonearm can not resonate in any way and should have frictionless bearings. 

There is no perfect tonearm, but in evaluating tonearm designs I think it is helpful to keep this in mind and make as little compromise as you can, picking the compromises that are least harmful. When you add into it that you are dealing with a sprung suspension and an unavoidable resonance problem the cartridge itself becomes an important factor in the design of every tonearm and has to be kept in mind. 

So, there is this push-pull situation in tonearm design. Fixing one problem makes other problems worse. I believe, since there is always a threshold under which problematic issues become inaudible, the appropriate approach is to minimize all the problems in a balanced fashion and hopefully bring all of them in below the threshold of audibility.  Many very smart engineers have looked at this problem and the vast majority of them have decided that the 9", pivoted, offset tonearm does this best. Newer tonearm designs utilizing the Thales algorithm like the Schroder LT and the Reed 5A and 5T may advance tonearm design to the next level. The principle makes enough sense that I would be willing to try it. Carriage driven tangential tonearms also make sense but are much more complicated and expensive to make. I put air bearing arms and this Viv arm in the same category, arms that optimize one or several factors at the gross expense of another which I find unacceptable. Maybe the distortion caused by this is inaudible to some people, but it is there and is audible to some of us.  

Lew, if you look at the business end of the Schroder arms he uses the same design on all of them, a cartridge mounting plate is attached to the end of the arm with one screw in a slot. So the cartridge can be twisted within a certain range and the overhang can be adjusted withing the range of the slot. If you mount the cartridge with only the inboard screw you can twist it straight and slide it back creating an underhung arm without any offset. This may not work with all cartridges but it does with the MC Diamond because I tried it. This configuration definitely caused enough havoc with imaging that I am pretty sure I could pick it out reliably in a blinded AB situation.