Rene,
I reread the article and understand that a key aspect of it is your question, "Is it really VTA/SRA changes that we're hearing or is it something else?" Apologies if I seemed to be dismissing it. This article has been used or mis-used both here and elsewhere by those with non-scientific motives. I suppose I was responding to those rather than to the article itself.
"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'"
That is a good question. Finding answers could indeed lead to improvements in music reproduction on vinyl. Even if the TT is perfect, many records are not. Neither Rushton nor I have vacuum hold-down, though I do use a periphery clamp. Even with two clamps however, some records just aren't flat. This makes the question very interesting. Wish I could suggest a satisfactory answer, but at the moment I can't.
The theory of changing resonant behavior doesn't seem completely satisfactory when the same differences are being reported across multiple, high quality rigs. I wonder if that theory came from the well-observed behavior of Rega style arms, which DO change audibly every time you adjust the arm locking nut?
It is *possible* to carelessly adjust arm height on a TriPlanar in such a way that its sonic character *might* be effected. The VTA tower raises/lowers the arm on a large diameter threaded rod. The good aspects of the design include a long thread contact area, to prevent wobbling about the vertical axis, and a set screw that pulls the entire mechanism tight against the outer housing. Lots of contact area, not just one screw point. Still, as with any mechanical device, there is some play in the mechanism. For example, one can approach any given arm height setting from either above or below. If one approaches a particular setting from above, the slack in the threads may not all be taken up. For this reason, I always adjust by bringing the mechanism *up* to a setting before locking the set screw. I can actually feel the weight of the arm moving up, so gravity is helping defeat any looseness in the threads. I also give the arm support a little nudge back and forth while turning the set screw to lock the setting in. This assures that the set screw mechanism is solidly seated. When carefully adjusted like this, a TriPlanar is quite rigid. Once it's locked down, any attempt to move the arm mount in any direction simply moves my 60 lb. turntable, without affecting the arm mount itself as far as one can tell by feel. No, I'm not going to pick up the table by the tonearm to test that!
I suppose it's possible that the mechanism's resonant behavior could change when I raise or lower the arm a few thousandths of a mm, but the kind of musical changes I described above don't seem to be consistent with that model, at least to me. They seem more consistent with the idea that the timing of when the playback stylus hits each individual groove modulation must match the timing as they were originally cut. SRA in other words. :-( Back to where we started.
Thank you Rushton and Restock for your supportive comments, and for even taking the time to unearth examples of why these attacks are without basis. I guess that's what honest men do. This little vendetta has appeared on multiple threads in the last couple of weeks, for whatever reason. I have chosen not to respond so as not to contribute to any deterioration in our normally enjoyable atmosphere. I will continue that policy. We all disagree from time to time, but that's no reason to poison the room. One wonders why the moderators haven't stepped in.
One point Raul made does need elaboration. "The industry standard for cutting head VTA is 20 degrees..." That may be true today, but manufacturing variances happen at all times and millions of records were cut before the standard existed. Old Deccas/Londons, for example, were cut at lower angles than more modern ones. If one only listens to recent releases then Raul's point would be more valid.
Golly, I sure hope Rushton's platter is flatter than mine. He paid enough for it. Why don'cha know, last Summer my li'l Teres actually absorbed 158 pounds of airborne moisture (Raul measured it for me). Why it blowed up so much it looked like Jabba the Hut. The spindle turned into an "inny"!
I reread the article and understand that a key aspect of it is your question, "Is it really VTA/SRA changes that we're hearing or is it something else?" Apologies if I seemed to be dismissing it. This article has been used or mis-used both here and elsewhere by those with non-scientific motives. I suppose I was responding to those rather than to the article itself.
"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'"
That is a good question. Finding answers could indeed lead to improvements in music reproduction on vinyl. Even if the TT is perfect, many records are not. Neither Rushton nor I have vacuum hold-down, though I do use a periphery clamp. Even with two clamps however, some records just aren't flat. This makes the question very interesting. Wish I could suggest a satisfactory answer, but at the moment I can't.
The theory of changing resonant behavior doesn't seem completely satisfactory when the same differences are being reported across multiple, high quality rigs. I wonder if that theory came from the well-observed behavior of Rega style arms, which DO change audibly every time you adjust the arm locking nut?
It is *possible* to carelessly adjust arm height on a TriPlanar in such a way that its sonic character *might* be effected. The VTA tower raises/lowers the arm on a large diameter threaded rod. The good aspects of the design include a long thread contact area, to prevent wobbling about the vertical axis, and a set screw that pulls the entire mechanism tight against the outer housing. Lots of contact area, not just one screw point. Still, as with any mechanical device, there is some play in the mechanism. For example, one can approach any given arm height setting from either above or below. If one approaches a particular setting from above, the slack in the threads may not all be taken up. For this reason, I always adjust by bringing the mechanism *up* to a setting before locking the set screw. I can actually feel the weight of the arm moving up, so gravity is helping defeat any looseness in the threads. I also give the arm support a little nudge back and forth while turning the set screw to lock the setting in. This assures that the set screw mechanism is solidly seated. When carefully adjusted like this, a TriPlanar is quite rigid. Once it's locked down, any attempt to move the arm mount in any direction simply moves my 60 lb. turntable, without affecting the arm mount itself as far as one can tell by feel. No, I'm not going to pick up the table by the tonearm to test that!
I suppose it's possible that the mechanism's resonant behavior could change when I raise or lower the arm a few thousandths of a mm, but the kind of musical changes I described above don't seem to be consistent with that model, at least to me. They seem more consistent with the idea that the timing of when the playback stylus hits each individual groove modulation must match the timing as they were originally cut. SRA in other words. :-( Back to where we started.
Thank you Rushton and Restock for your supportive comments, and for even taking the time to unearth examples of why these attacks are without basis. I guess that's what honest men do. This little vendetta has appeared on multiple threads in the last couple of weeks, for whatever reason. I have chosen not to respond so as not to contribute to any deterioration in our normally enjoyable atmosphere. I will continue that policy. We all disagree from time to time, but that's no reason to poison the room. One wonders why the moderators haven't stepped in.
One point Raul made does need elaboration. "The industry standard for cutting head VTA is 20 degrees..." That may be true today, but manufacturing variances happen at all times and millions of records were cut before the standard existed. Old Deccas/Londons, for example, were cut at lower angles than more modern ones. If one only listens to recent releases then Raul's point would be more valid.
Golly, I sure hope Rushton's platter is flatter than mine. He paid enough for it. Why don'cha know, last Summer my li'l Teres actually absorbed 158 pounds of airborne moisture (Raul measured it for me). Why it blowed up so much it looked like Jabba the Hut. The spindle turned into an "inny"!