![]() ![]() |
Vinyl Asylum Welcome Licorice Pizza (LP) lovers! Setup guides and Vinyl FAQ. |
For Sale Ads |
Use this form to submit comments directly to the Asylum moderators for this forum. We're particularly interested in truly outstanding posts that might be added to our FAQs.You may also use this form to provide feedback or to call attention to messages that may be in violation of our content rules.
Original Message
Makes sense to me.
Posted by garth on November 18, 2005 at 08:28:26:
I think and visualize in 3-D so math is a bit "flat" for me. :-) But nevertheless it is perfectly logical to me that the further away from the pivot on the suspended side (read cartridge side) mass is added the more it effects effective mass, (is it four fold or to the power of two). So adding a little at the headshell increases effective mass more than the same amount at say 1 cm from the pivot or at the pivot.
Conversely adding mass on the other side of the balance (pivot) decreases effective mass. Move it coloser and/or increase the mass and the effective mass goes down.
It also is not surprise that the amount of eff mass reduction from increased C/W mass is quite small, it is after all very close to the pivot.
What about this: increse the mass in a way so it centered about the pivot, that is equidistant from it in all directions. It should add no effective mass but will it not increase the moment of inertia?
I see it this way, at this is nothing new, the tonearm should be free to move in all directions, natch, but shuld through it's inertia resist any lateral movement. Only the stylus/cantilever shuld move to the undulations of the groove but not the tonearm. Vertical movement shuld be free of inertial effects, in theory, to allow exact following of the groove during warps.
That said it seems to me the moment of inertia shuld be high as possible in the horizontal axis independant of the effective mass
That the Schröder arm for instance. It hangs from a single point and abslutely free to move in any direction with a total lack of friction. The attracting magnets create the moment of inertia in the range of several Kgs, not grams as in a conventional arm. Arm material is changed to adjust effective mass for cartridge compatibilty. The inertia is adjustable via the magnet gap. it may not be the perfect solution but pretty close.
Cheers and good luck!