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Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ. |
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Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ. |
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In Reply to: I agree with Baerwald being mathematically attractive, but... posted by travisty on May 2, 2011 at 03:16:58:
> On a practical basis however, if one has standard mounting distance according to a standard IEC template,
> the EFFECTIVE best alignment for any given record made in the past 25yrs could easily be Löfgren B because so
> many of them have their last modulated groove radius even before the Baerwald inner null point.
The problem I'm having is how to address this sort of misunderstanding and misrepresentation of alignment methodology. The alignment terminology labeled Löfgren, Baerwald, Stevenson, etc., is not a terminology based on a specific set of null-points but on a specific set of beginning and end points for the modulated groove area. When you say that you believe that Löfgren B might be the better alignment because "many LPs have their last modulated groove radius even before the Baerwald inner null point," you demonstrate a misrepresentation and a misunderstanding of alignment methodology. An LP can never have its last modulated groove radius occur before the Baerwald inner null point. The definition of Baerwald, which we now call Löfgren A, always places the inner null-point well inside the modulated groove envelope. Only Stevenson's alignment has its inner null-point coincident with the innermost modulated groove.
For example, if you have Löfgren's A alignment with null-points at 66-mm and 121-mm and you switch to an LP with its innermost modulated groove at 66-mm, your alignment is no longer Löfgren's "A" alignment. Now it becomes Stevenson's alignment. Therefore, you need to be talking about specific alignment null-points instead of mislabeling them Baerwald, Löfgren, or Stevenson. Your concern is that the inner null-point should be placed at a specific point in order to achieve the best compromise for the vast majority of LPs.
My point is that if you do not want to compromise your alignment you should measure the beginning and ending groove radii of each LP and realign your tonearm for Löfgren's "A" alignment for each individual LP. This is because Löfgren's A alignment produces the lowest overall distortion compared to any other alignment methodology. On the other hand, if you want to compromise and select a permanent set of null-points, the label you place on them (Löfgren, Baerwald, Stevenson) will actually change with each LP you play depending on its innermost and outermost groove radii.
> Stevenson null points are not generated off groove radii like the Löfgren A & B are.
Not true! Stevenson's alignment is simply Löfgren's "A" alignment with the inner null-point at the innermost groove. In other words, Stevenson's alignment minimizes tracking error distortion across the modulated groove envelope with the caveat that the inner null-point must be coincident with the innermost groove. For example, suppose you had an innermost groove radius of 54.8-mm and outermost groove radius of 146.05-mm. Löfgren's "A" alignment would yield null-points of 60.325-mm and 117.42-mm. These are also Stevenson's null-points for an innermost groove of 60.325-mm and outermost groove of 146.05-mm.
The truth of the matter is that everyone who came after Erik Löfgren simply reproduced Löfgren's equations in slightly different form. There is really nothing new in tonearm alignment since Professor Erik Löfgren published his original paper in 1938.
Best regards,
John Elison
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Follow Ups
- RE: I agree with Baerwald being mathematically attractive, but... - John Elison 10:56:44 05/02/11 (1)
- Thanks for correcting me on Stevenson - travisty 17:35:45 05/02/11 (0)
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