Removable headshells 101


Due to the influence of Raul's thread on MM cartridges, I believe that some of us (perhaps for the first time), have acquired a tonearm/s with a removable headshell?
In my case, there was a vacuum of knowledge or information about what makes a good headshell and for the last 6 months a great deal of my time and effort has been expended in acquiring personal hands-on experience.
Perhaps a Forum to share experiences will help new adherents to this once denigrated (by the High End) segment of tonearm design?
128x128halcro
Thinking further on this, it seems to me that any headshell with such poor structural integrity that one could "actually see the shell convulsing", then it could be twisted (albeit slightly) by hand as well. I mean, how much energy does the stylus/cantilever generate as it traces the groove?

The Orsonic I purchased appears to be very rigid, at least to attempts to twist it by hand.

Now I'm not suggesting that Henry and Raul are wrong about the lack of good sonic qualities. But I am inclined to try it for myself before discarding it -- and yes Raul, with a few different cartridges to see if I find a match.
Pryso,
The forces transferred into the headshell can be large on a microscopic level 'if' they allowed to be magnified by poor structural design and/or rigidity.
If you examine the design o the Orsonic headshell you will see that the bulk of the aluminium structure is elevated above the pin socket which connects to the headshell.
This creates a 'lever arm' for a bending moment and the larger the lever arm.....the greater the bending moment proportional to the square of the lever arm.
The connection of this headshell to the socket itself on the Orsonic (or the copies)......is weak and poorly designed.
If you fix your Orsonic onto the tonearm......try holding the tonearm steady and whilst gripping the headshell at its extreme end......try twisting it back and forward.
This should illuminate the problem :^(
Wood VS the rest,..tests done by Reed tonearms in the research section of their web site have illustrations of acoustic vibration traveling through a table you may find helpful.

Orsonic, there seems to be an endless supply of this rare and short lived brand coming from somewhere, including a brand new box with it.
Regards, Dlaloum: TA = ToneArm. Vibration analysis is such a complicated branch of physics there may be a few professionals who can understand all of it, you can be assured I'm not one. Perhaps not a "black art" but it is a subject prone to generalizations. Building on your comments and Henry's most recent post, permit me a few?

My rudimentary understanding is that a vibration, emitted from a source point, “propagates” and follows the path of least resistance, somewhat like the ring of waves seen when a rock is tossed into a puddle. When these vibrations meet a border between two surfaces, they split, part reflected back and the rest continuing along the second body. How much goes where depends on the acoustical impedance of these materials.

Resonances are characterized by selection of materials, geometry or various devices attached to this body. These resonances may be reflected, amplified and reflected again until the source of the excitation ceases. Mass, materials, wether hollow or solid, holes, stress, associated materials this body is in contact with, texture or coating of the surface (skin effect) and physical configuration (straight/curve/taper/length) all have a consequence in frequency, amplitude, or transient behaviors. From my layman's perspective (read poorly supported opinion), if I intentionally selected a questionable design it would incorporate a removable headshell, and I did.

All this is so very complicated some simplifications are, for me, a neccessity. There are three means of address or correction available in my limited tool kit: Vibrations can be damped, reduced, or tuned. Selection of headshell material and mass are means of addressing these concerns, the choice of wether to retain the o-ring at the coupling is another. Cartridge isolation is also an influence long recognized. I'm reminded of the dimpled triangular alu. plate Grado offered as an option in the late '70's. There are some who are now exploring hard-points between the cartridge and headshell, "tip-toes" for your cart.

Although some of the above statements are probably accurate, I hope you'll correct me where wrong. None the less, a trial and error approach still seems sensible. Was it Voltaire who said, IIRC, "Best" is the enemy of "Better"?

Peace,
Well my experiments with resonance damping on arm & headshell have failed miserably...

Not because it doesn't work, but because my current test track/measurement method has accuracy that is around +/- 0.25db....

That results in variations of up to 0.5db between two readings of the same setup....

My gut feeling looking at the plotted results is that I can see a shift, but it is small (less than 0.5db) and not demonstrably repeatable...

Bye for now

David