Glossary
um = Micrometer (read: micrometre) - Unit of length.
mN = Millinewton - Unit of measurement of force.
um/mN = micrometer / millinewton
g = Gram (Weight)
cm/dyne = (Dyne per Centimeter) - Unit of measurement used primarily for surface tension.
cu = compliance units ( ~ elasticity of suspension)
compliance = inverse of stiffness in relation to phonograph cartridge suspension which may apply to both horizontal and vertical planes. (Ex. Low = stiff / High = soft) Static compliance = measured at rest / Dynamic compliance = measured under modulation. Typical published cartridge specification figures are measured @ 10Hz, however, in certain cases measurements may indicate 100Hz (ie. Japanese) based calculations.
effective mass = A complex calculation, in brief this term determines the moment of inertia of the tonearm about the pivot point, calculated by the equivalent mass required at the effective tonearm length to provide the same moment of inertia, and this “mass” per se equates to the net effective mass.
resonance frequency = Frequencies at which the response amplitude is a relative maximum are also known as resonant frequencies or resonance frequencies of the system. Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude oscillations in the system due to the storage of vibrational energy.
Phonograph cartridge and tonearm resonance frequency = When selecting either MC, MI or MM cartridges for your record player, the total mass of a tonearm (including cartridge and headshell) must be taken into account in relation to the mechanical compliance (elasticity) of the cartridge cantilever system. Refer Ortofon article. Link
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Why phonograph cartridge published Dynamic Compliance figures can be misleading - Part 1 & Part 2