Hi Goatwuss,
high effective masses are not bad and low ones neither. The influence of warps is not different for high and low effective masses, as long as the resonance frequency is the same.
So there must be the right dynamic compliance for a certain effective mass to attain a resonance frequency which is high enough to ensure stable tracking.
Your headshell rests right upon yr cartrdge. So the headshell- influence on the stylus suspension is higher than a part located closer to our arm- pivot. The vitual sum of all these mass-influences seen from the tip- location is called effective mass.
Basically we talk about a mass- spring- combination here. Our tonearm/ cartridge combination should work like a suitable seismic filter, which isolates the relative movements of our tip relative to our headshell. It isolates these movements from warps, modulation- rubbish coming from the groove and energy coming from the floor.
At a modulation- frequency of 8 Hz we still find rubbish and warp- energy coming from the vinyl- groove. The real silent region is from 10 to 14 Hz. So there we must locate our resonance frequency, independant of the current effective mass.
Mass is not the same thing as force. Just imagine that a planet in space may have a very high mass but perhaps could not experience any force working upon it. But try to stop it's movement with your own hands and you will not end the job alive, I fear.
But a higher effective mass is not a bad thing on it's own, as long as there is a low enough dynamic compliance to keep our resonance frequency high enough.
This effective mass can be calculated after the estimation of the current resonance frequency.
The calculation of the effective mass of an arm can be done as follows too:
Calculate the sum of all specific products (armpart- mass) x (part - to- pivot- distance)^2 of each part of the tonearm and divide this product by (effective lenght)^2.
Appr, one year ago we have read an interesting topic at this forum dealing with resonance frequency. Look for it using the search- window.
In the library of the Vinyl Engine Forum an interesting english- written danish AES- paper by P, Laadegaard can be found which I see as the best one upon this mattter published ever.
Jan.
high effective masses are not bad and low ones neither. The influence of warps is not different for high and low effective masses, as long as the resonance frequency is the same.
So there must be the right dynamic compliance for a certain effective mass to attain a resonance frequency which is high enough to ensure stable tracking.
Your headshell rests right upon yr cartrdge. So the headshell- influence on the stylus suspension is higher than a part located closer to our arm- pivot. The vitual sum of all these mass-influences seen from the tip- location is called effective mass.
Basically we talk about a mass- spring- combination here. Our tonearm/ cartridge combination should work like a suitable seismic filter, which isolates the relative movements of our tip relative to our headshell. It isolates these movements from warps, modulation- rubbish coming from the groove and energy coming from the floor.
At a modulation- frequency of 8 Hz we still find rubbish and warp- energy coming from the vinyl- groove. The real silent region is from 10 to 14 Hz. So there we must locate our resonance frequency, independant of the current effective mass.
Mass is not the same thing as force. Just imagine that a planet in space may have a very high mass but perhaps could not experience any force working upon it. But try to stop it's movement with your own hands and you will not end the job alive, I fear.
But a higher effective mass is not a bad thing on it's own, as long as there is a low enough dynamic compliance to keep our resonance frequency high enough.
This effective mass can be calculated after the estimation of the current resonance frequency.
The calculation of the effective mass of an arm can be done as follows too:
Calculate the sum of all specific products (armpart- mass) x (part - to- pivot- distance)^2 of each part of the tonearm and divide this product by (effective lenght)^2.
Appr, one year ago we have read an interesting topic at this forum dealing with resonance frequency. Look for it using the search- window.
In the library of the Vinyl Engine Forum an interesting english- written danish AES- paper by P, Laadegaard can be found which I see as the best one upon this mattter published ever.
Jan.