Graham Phantom vs. Phantom II

Dertonarm,

The damping does in fact damp the tonearm. It is a resistance to motion or vibration. It would change how the arm behaves dynamically.

Below is a quote from another website. This is the best summation of what is effective mass and how the distance of the counterweight (obviously in relation to the weight of the cartridge) does change a tonearm's effective mass.

"Equivalent Mass of counterweight at stylus tip=M*Lb^2/La^2(g)
If counterweight M weighs: 120g for example
Lb=counter weight centre mass distance from pivot: 5cm for example
La=effective length of arm from pivot to stylus: 24.5cm
Then "equivalent" Mass of counterweight as seen from stylus point can be calculated approx 5g.
Thus adding effective mass 5g on the cartridge+shell (when ignoring other masses of wand and fitting etc).
Effective mass is changing in accordance with the position of counterweight to balance the head mass so that "any" effective mass of arm is only "nominal or representative" value - useless for determining the actual resonance frequency expected from cartridge compliance and total effective mass (especially when the counterweight shaft is elastically connected with arm body as in "DYNAMIC DAMPING MECHANISM")."

Now to go beyond this explanation, I will add that a lower mass counterweight further away from the pivot in fact resulted in a lower resonant frequency for the same cartridge in the same arm. This gave me close to an 10Hz resonant frequency with extreme sonic benefits.

I myself did sonic tests comparing lower mass counterweight away from the pivot and a very heavy counterweight close to the pivot. I preferred the result with the lower mass weight away from the pivot. This in effect explains that the cartridge/arm type and combination is important in determining what is best.

I myself don't subscribe to the universal rule that is being put forth that the closer the counterweight to the pivot the better the performance of the arm.

Now, lets take what many people mention in regards to any of the dynamically balanced arms where the VTF is via a spring. Many suggest to disengage the dynamic VTF and use only the counterweight. I would suggest that this is more a function of the cartridge and arm combination. That in fact the best sound might result from a combination of the 2. Some dynamic VTF & some static VTF. This would yield an ideal combination in some cases. In the case of my Breuer this is easily realized. So in the end the cartridge sees the spring and the counterweight as a form of mass in terms of VTF. Effective mass can not be a defined number for a tonearm.

Dgad, let me quote myself:

"The distance of the counter weight from the pivot does NOT determine the effective mass of a tonearm.
The damping fluid is located circular around the pivot and thus the amount do have ZERO effect on the moving mass of the tonearm."

Now tell me, what your post 09-15-09 - which is obviously written as a direct answer - does have to do with what I said ?
I said that the distance of the counterweight does not DETERMINE the effective mass of the tonearm (take for instance that the countermass is not a moveable weight, but a fixed shaft or a ball - to illustrate the principle...).
And of course does a circular located damping fluid has no effect on the moving mass. It would certain had if it was located in the armtube (which it isn't for obvious reasons).

And yes - we all had the model of the simple lever and the very easy calculation of force being a result of mass and distance in fairly early high school (my sons turns 11 next year and it is in his curriculum for next school-year) - you do not need to search for it on the web.

Let me quote myself once again:

" This is the effective moving mass sans the cartridge. So the effective total mass is always and in any tonearm depending on the added cartridge body weight and the distance this added mass (the cartridge body) has from the pivot. "

Just give it a brief thought, why certain (most..... if technically allowed by their design....) tonearm designers do offered their products with a range of different mass counterweights (even - and especially so - if dynamically damping mechanism (Technics) was incorporated in the design...).
And sorry - physic does not care, whether you personally preferred in your specific set-up and with your taste in sound a low mass counterweight further away from the pivot vs. a higher mass closer to the pivot.

Again - the (obvious... if sad) fact that still most audiophiles do not understand the true nature of dynamically balanced mode and its very special interaction with the cantilever's suspension isn't physics problem either.
That several do prefer a mix of balanced and static mode is certainly fine with me, but is again a result of their sonic preference in their specific set-up and viewed (heard) through their individual matrix.
That try and error in audio does give individual satisfying results is great - that these great results all too often loose their magic touch in a few days or weeks should tell something.
The proof may be in the listening for some - but it is always an individual proof suitable of the one recipient only.
And many times just a lucky cross-out and vice-versa compensations of many sonic mistakes.

The fact that even Joseph Stalin was once backed by a large portion of his people did not make him a great statesman and philanthropist either.
Sorry again, - but this is not an empirical nor an objective set-up according to any scientific rule.
It is a personal impression as a result of a complex bundle of variables and viewed through a private matrix of preferences all your own.

Dgad, I do not want to lecture you nor anybody else.
As you wouldn't believe me anyway let me just suggest you send a PN to Schroeder or Bob Graham - you are in possession of both designers babies and they will happily explain the points to you.

Dertonarm,

I can't be bothered to argue with you but you are wrong. There is effective mass & nominal effective mass. Please understand the difference.

By the way such also applies to effective length of a tonearm.

Dgad, great - now you tell me I am wrong.
O.K. - wrong, but.... wrong with what ?
Anyway - after having learned so much from your two posts, I won't die a stupid man.............
Syntax - you were so right!

Dertonarm

Your physics seems to be faulty here. Assuming that the counter weight is indeed firmly connected to the tonearm tube (which is always the case in a well designed pivoted arm), then, the effective mass of the arm must be dependent on the distance of the counterweight from the pivot (ie. the moment of inertia “I”is dependent on the radius squared). The composite "I" for the arm tube/counterweight and subsequently the "effective mass" would essentially have the same dependency.