Cartridge ISOLATION; What Say You?

The reason the stylus vibrates in the first place is the record groove hits it. Therefore, equal and opposite, just as much vibrational energy goes into the record as the cartridge. Equal and opposite.

Conservation of mechanical (vibrational) energy is not a law, but conservation of energy is. Therefore the vibrations are not necessarily equal.

I have a few Decca cartridges. Been using them since the 80s. When I upgraded two of them from the red bendy plastic fitting to the milled aluminum Decapod, I noticed a specific change to the presentation of music. The improved and more rigid mount tightened the music, if you will, lending more stability to the image, faster transients, reduced sibilance, slightly larger and blacker soundstage. While I prefer the accuracy, and would never go back, I will say that it did reduce the musicality of the device. Just a little but it did raise the question of why. Why did it sound more musical? Colorations from vibrations? Harmonics?