by Harry » Thu Jul 12, 2018 12:16 pm
Whew! A lot to digest for an old retired guy.
1- The inertia issue only becomes an issue when the arm is being forced to move due to warps, we flatten the record using our periphery ring which removes one major hurdle.
2- The effective mass issue is a red herring when you 3D print the arm as you can control the mass precisely and the 12" has minor effective mass gain over the 9".
3- The material used to construct the arm has more effect on the sound than the length because the way vibration is transmitted, the amount that is dissipated, and the true mass of the arm is so effected by the material used there is no way to isolate the variables. 3D printing all three arm lengths removes these variables as the mass is almost the same for all three, the material is exactly the same, the rigidity is the same other than the length issue. A very logical way to test arms.
4- The arm tube from the bearing assembly forward is the only part 3D printed the back end of the arm is aluminum and stainless steel and all three lengths use the same back, there are no other variables introduced.
5- The 12" version creates less skating force so immediately it has the advantage as skating force and the removal of it is very detrimental to the sound quality. For me using minimal or no skating force is a way bigger positive than shorter length.
Leaving out having all these mounted on the same ultra low speed error table is missing a major point. No one has done this but VPI. We have an ultra stable, ultra accurate, non feedback possible system, using all three arms that are exactly the same other than length and using three matched cartridges. End of discussion, no one else has or can do this.
Plus, do not dismiss the fact that we have the same tape machine as the machine the tape was made on. Running one of those master tapes on a Studer, while a great machine, is not the same machine and that matters.
HW