- vladan3101
- Posts: 17
- Joined: Thu Nov 03, 2022 1:53 pm
JAES paper or distortions due to lateral tracking error
I did not think that this paper could be of much interest here because it deals with the problems in LP reproduction, not the production itself, but 340 views of the post about the tracing paper (https://www.lathetrolls.com/viewtopic.php?f=1&t=10062) in less than two days made me think I might have been wrong.
Unlike the tracing paper, which was mainly a historical survey with little original material, this one has a complete analytical solution for the optimum overhang and offset angle for the so-called “Löfgren C” alignment (Least Mean Squares distortion over the disk, rather than the Tchebyshev or mini-max optimization criterion, aka “Lofgren A” and “Bearwald” alignment).
The problem has been unsolved since 1938, when it was initially formulated by Löfgren [3], but it is mainly of theoretical interest. The most important practical result is that tracking error null radiuses (where the protractors for “Löfgren C” force the zero error) should be at 70.0 and 116.0 mm rather than at 70.3 and 116.6 mm as the previously used approximate formulas suggested, but that difference is probably too small to be audible in any practical circumstances.
The complete paper is available for free (without a subscription to AES) at https://www.aes.org/e-lib/browse.cfm?elib=21560. Their Open Access policy allows free downloads but does not allow posting the paper on other sites.
- p1cturelamp
- Posts: 7
- Joined: Sun Jun 04, 2023 3:45 pm
Re: JAES paper or distortions due to lateral tracking error
Sounds useful! Hope AES's research yields fruit and brings this old issue to light!
- vladan3101
- Posts: 17
- Joined: Thu Nov 03, 2022 1:53 pm
Re: JAES paper or distortions due to lateral tracking error
It already created some further research. Peet Hickman published "Analysis of Löfgren's Tonearm Optimization" in the Jan. 2023 issue of JAES, see https://www.aes.org/e-lib/browse.cfm?elib=22031. Unfortunately, this paper is not published under the Open Access policy, so it can be downloaded for free only by members of the Audio Engineering Society. Others have to pay $30.p1cturelamp wrote: ↑Mon Dec 18, 2023 3:20 pmSounds useful! Hope AES's research yields fruit and brings this old issue to light!
That paper confirmed my main result but also provided new derivations for practically all known results for all 3 of Lofgren's alignment cases (A, B and C) and provided very interesting asymptotic approximations.
Even more impressive is that the author seems to have solved the problem that nobody solved from 1938 to 2022 by hand –- in my paper, I used symbolic calculation software. I reported what I did but still feel it involved a form of cheating. His paper did not.