Gnason wrote,
"Most turntables from medium to high end have a vibration suppression system built into the unit."
The trouble is when turntables do have some sort of vibration ISOLATION system built in, such as spring system, the built-in isolation system is not nearly as effective as a very competent outboard isolation system. The spring rates of the on board spring systems are just not as low as they should be to be effective. Obviously, the cartridge and tonearm are designed with very low resonant frequencies, which is intended to suppress acoustic vibration, but are still susceptible to very low seismic type vibration. While damping and resonance control for turntables might be issues, they are not substitutes for vibration isolation. Furthermore, some damping techniques are more effective than others. There’s a damping gap. 😳