Discuss The Viv Lab Rigid Arm

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.