Is extremely accurate "VTA" adjustment necessary?

Thank you Rushton and Tom for your contributions here.

I think the question here is whether changes of 0.1mm in tonearm height are actually necessary. I would agree based on my personal experience that changes on the order of 0.5mm to 1mm do make a difference. The question is more about smaller changes than that.

The problem is that I have to mostly agree with the article. Following the same geometrical argument I do also think that the variations from cartridge to cartridge, temperature fluctuation, thickness variations in records (even in audiophile ones) are much bigger change the vta/sra angle more than a tenth of a millimeter change in the tonearm height.

Looking at my turntable and even with a record clamp and an unwarped LP you see changes in the record of more than 0.1mm which would say that the vta/sra angle changes as much as if you would change the tonearm height on the same order. On a highly resolving system this would change the sound as the LP goes round at 33rpm. This would be quite damning result for music reproduction through LPs. I good measurement of the thickness variations is to shine a laser pen on the record and look at the reflected light some meters away. You then geometrically determine the difference in height as the record goes round. My guess is that unless you use an inner and outer record clamp you will have variations bigger that the 0.1mm adjustment possible on some tonearms. Otherwise one could be quite busy adjusting the VTA as the record turns.

I would think in agreement with the author that mechanical stability, when a more staple thread of the VTA adjuster is hit, accounts for most of the difference in the sound for these tiny adjustments. Rushton, this could for example explain your observation a couple of months ago, when adjusting vta and hitting a "mechanical" sweet spot.Roy Gandy would be really happy about this argument, although I think he goes to the other extreme by not providing any possibility of vta adjustment on his arm.

A good example is the new vta adjuster for the Teres turntables. They allow adjustment of the vta to 0.0254 mm (1/1000 inch). If we can here differences in the sound on that order we really would be distracted by the VTA variations during the turning of a record. On the other hand I do see a good reason for this degree of fine adjustment. If I can adjust the vta by 0.0254 mm I can set a more reasonable 0.25 mm very accurately and reproducible. Also you have ten possibilities to hit a good thread.

Meine zwei Pfennige...

Rene

Doug thanks for your insights. I know that you and other (TWL etc.) probably know a lot more about this than I do. After all I have only been into analog for a little more that 10 years. I just would like to make some point before you dismiss this article completely.

I think the author does agree with you that different thickness of records need different arm height adjustment, and that you will hear that difference. After all the difference between a thick and thin record can be quite substantial and on the order of an mm. The question here is more on how accurate does it have to be. If 0.0254 mm difference is audible on your system, I think you should hear a variation in your sound as the record turns, since the record thickness is varying more than this. Do you?

Sorry, but this might get quite controversial now. As a physicist I got to take issue with the following statement:

"As for that article, to me it's just another pointless argument offered by a theory-blinded engineer trying to "prove" that I can't hear what I hear."

- First of all the article does not say that you won't be able to hear differences in VTA adjustment.

- Second it does offer an explanation for what you hear if you do micro adjustments. It is just that what you hear might not be the vta/sra adjustment itself but more the mechanical rigidity of the tonearm mounting and selecting a good thread. In particular the triplanar arm might just offer you ten settings with the same average vta (across a record) that offer different rigidity of mounting. This probably is better that if you had only one good setting available. And my guess is that you will hear all the different settings on a good resolving system, except the reason is not the VTA or SRA angle.

- Third, his arguments are purely geometrical, not scientific. The argument just you that other geometric variations are much bigger than adjusting vta to 0.0254 mm accuracy and which should have a bigger impact on the sound. All this discrepancies and error are clearly measurable and like I said you might actually hear them. But then you should hear the VTA adjustment varying as the record is rotating as well.

As a physicist I do believe that there are a lot of things you will be able to hear in a good system that are not measurable and maybe not even scientifically explainable yet. These are complex physical systems and much more difficult to describe than most engineers think. However, geometrical changes in the vat angle just does not seem to be the correct explanation for this phenomenon of being able to hear extremely fine changes in VTA. In particular with turntables resonance control, vibration control, and rigidity are very important. There’s s lot of deaf (and blind) scientist and engineers out there, but this example does in my opinion not fall into this category.

Also the other important point here is that if we know what is going on, maybe there are better engineering solutions out there. The Teres project is a great example for this.

All the best,

Rene

One question I forgot to ask everybody here:

How accurately do you adjust the VTA via tonearm height adjustments (0.02mm, 0.1mm, 0.5mm, 1mm)? For example Rega spacers are 2 and 4mm, which is certainly does not seem to be enough.

Rene

Decay, how thick are those spacer record mats that you add for thin LP's?
This does seem a like good option, since you are not disturbing the mechanical aspects of the arm mounting. However, like many popular tables mine does not use any record mats, which makes this impossible for me.

(sorry for adding another answer to the thread hear, I should learn to answer everybody in a single response..(:-)

Rene

Hi Rushton,

I do not dispute that you and Doug and others are hearing these changes.
And I do trust your ears and system more than mine. To keep my question
short and precise: My question after reading the article is just: Why don't we
hear the variation in VTA as the LP rotates, since this variation is much bigger
than changing the armheight by .005'. This was really the technical problem
that stroke me the most when reading the article.

I guess we can't really tell the change in sound over a two second period but
then we all can hear diffrences over a much shorer timescale than that. It
seems to me from your experiences It might be just the average vta that
counts for each record even if the errorbars are much bigger than that.

Oh, this doesn't come quite down to just intellectual curiousity. I am
deliberating to get a Teres table and I was wondering whether a $200 VTA
adjuster would make sense and whether I am giving up mechanical stability in
that case. The above article just caused myself to rethink some of what I have
heard here on Audiogon and elsewhere. I guess based on your experiences
maybe I should just give it a try.

Thanks again,

Rene

Thank you all for your responses.

4yanx - Thanks for your response. Of course I could just go ahead and get the vta adjuster anyway. I just wanted to have some more rational reasons before handing out $200 for vta. Since everybody here seems to agree that differences in record thickness need vta adjustment possibility, it would be difficult to find a better solution for the price.

Rushton - Thank you very much for all the details about the Walker Proscenium turntable. Out of own experiences I know that any tolerance below a thousands of inch takes a lot of effort and care and is certainly not cheap to produce. I very much doubt that my Michell turntable is even close in tolerances. I never had a chance to see the Walker table live, I would be very interested to see the solution they found for a rigid vta adjuster. Another number I am really interested in is the thickness variation of a record. I probably should call Classic records to find out what the tolerances are in the production of their current Quiex LP's. I'll keep you updated if I find out more.

Psychic - For now I was more thinking along the lines of an acrylic platter, which is probably closer in tolerances. I doubt I will be able to afford a Teres with wood platter anytime soon.

Raul - Thanks for your support. So far I haven't really worried too much about vta. I do have a Rega arm which is a pain to adjust on any table. The Michell vta adjuster (or the incognito for that matter) is fine but I suspect it is going to have exactly the mechanical problems mentioned in the article. The vta I found with the adjuster was actually close (less than +-0.5mm) to the 2mm Rega spacer, which I thought sounded actually slightly better when I changed it. I would certainly appreciate a more solid vta solution, however I doubt I will play with vta adjustment too much. I usually adjust everything in my system so that I really like the way it sounds and then usually just leave it alone for a while and just enjoy the music. As with respect to my experience in analog: I only have had three different turntables and four cartridges, which certainly does not make me an expert. Also I never really had a high-end setup. Also I do think Doug does give good and thoughtful answers. I have posted several times in the same thread as Doug and I always thought he was quite spot on. Also on Personal turntable/cartridge evolution he did mention that he had a various tables since 1967. (If you get a chance it would be great if you would post your history there as well.) Otherwise, I agree: Enjoy the music.

Also one more comment: I just think the science perspective on audio has always led to heated debates, and vta adjustment is right on the line in that respect. I would prefer though if we can keep personal attacks aside.

All the best to everyone,

Rene

Raul, Psychic, Jphii, 4yanx: Since all of you seem to missing Romy the Cat so much: Here's a nice treat for you all...

Romy the Cat - Forum

Thanks again to everyone for their responses and back to the original topic of discussion. I think many of the posts have been very informative and really helped a lot in answering the question of importance of micro adjustments of vta/sra. Sorry for not responding for quite a while. Here’s a collection of answers to various posts that occurred during my absence (dating back to 10/8/04)

Doug – Thanks for you very much for your responses and thanks for going back to the article and for taking a fresh and more neutral look at the article. Thanks for trying to answer my earlier question on why don't we hear the variation in VTA as the LP rotates, since this variation is much bigger than changing the arm height by .005'. I agree that it is very difficult to find a satisfactory answer to this question, in particular since you and many others do have systems that are able to resolve very small differences in vta adjustments via arm height. I am quite convinced that it is the actual minor change in the vta or sra angle that causes the audible differences, but I agree that the answer in the article seems not very convincing either. Your observations are no explainable by mechanical rigidity arguments, since changes in the sound that are due to the arm height change would not be as repeatable as they are if mechanical resonance behavior would be the answer. Also the construction of the TriPlanar arm seems to address the mechanical stability question already.

Thomas – I agree that azimuth is an issue that needs to be addressed in fine-tuning much more than vta. In particular since it is not even a question on which angle to choose. Too bad most companies choose to only hand you a mirror. I think there’s probably more people out there arguing and finding solutions to vta that finding good approaches to azimuth adjustments. Maybe a good time to start a new thread about azimuth…

Eldartford – I did not quite understand you comment on measuring the different critical parameters by reversing wires in one channel. Would you mind elaborating on that some more or eventually giving references?

Decay and Greggadd – Thanks for you discussion of measurement vs. adjustment by ear. In my opinion objective and accurate measurements seem almost not possible in this case. The missing knowledge of the correct cutting angle for each record as well as the inability to measure angles to an accuracy of less than a tenth of a degree seems to make accurate measurements impossible. Remember that I was talking about changes in arm height on the order or less than 1/10mm. Although measurements might give a good starting point but the ultimate measurement in this case seems to be the ear. Also one more question that you might be able to help me out: If one tries to adjust for a 2 degree variation in cutting angle, would that not correspond to a change in arm height by about 6mm? These are huge changes compared to the ones we were talking about earlier.

Again thanks to everyone for his or her answers.

Best wishes,

Rene

Update: Looks like there has been a lot more controversy about the vta article by Geoff Husband aside from this thread

Exposing the VTA myth?-Revised

The Great VTA experiment

Cartridge alignment Part 2

Well, I think I am certainly convinced now that my next table/arm combo will have the appropriate facilities for adjusting vta. After all this discussion I really need to try it for myself. There's nothing better than experiments, theory is not always a good substitute. I am note sure though whether I will get really obsessive about it, since I usually prefer to just listen without tweaking.

Doug, you really brought up another good argument earlier, although I think it is a very good one FOR vta adjustments if done properly. I also think that there is a chance that the cartridge alignment is off due to the slightly changed geometry when adjusting vta. However, for minute adjustment in VTA with a well-executed tonearm mount and vta adjuster, this should not change the geometry more than putting on a record of different thickness. This also would mean that we should certainly adjust for different record thickness to be true to the changed geometry.

Also this makes me really doubt the cheaper vta devices for Rega arms like expressimo and incognito. When you loosen the arm, change vta and then retighten, everything could have changed: The tonearm could slightly shift around in the mount changing cartridge alignment completely, you might hit an unstable thread on the mount, etc. Not the best method to get reproducible results. The bottom line is: If you want to bother about vta, you better do it right with a well-executed mechanism.

I really have to thank everybody here again. I thought the discussion was really helpful and really brought out some of the usually hidden issues in adjusting vta. And I do have to agree:

You can't ignore it but you don't need to worship its altar.

Again best wishes,

Rene