Actually the speakers move more without isolation. The very low frequency seismic type forces are causing the entire building to rock back and forth. The idea that speakers rock back and forth on springs or wobble is a f-f-fallacy. It’s the opposite. That’s the whole point of isolating anything. Hel-loo! That’s why electron microscopes are isolated on spring systems, so they won’t move whilst photos are taken of the sample. It’s a mass-on-spring SYSTEM. It’s not rocket science, guys. 🚀 That’s how they were able to detect gravity waves with the amplitude of an atomic nucleus - by isolating the optics and electronics so they wouldn’t move.
It might not be obvious to the casual observer 👀 but there is a limit to how big and heavy speakers can be due to center of gravity issues. BUT those limitations don’t apply to subwoofers which have relatively low centers of gravity. So, springs can go directly under the sub without all the rigamarole needed (a la Townshend Iso device) to get the springs in a wide pattern so the speaker will be stable.
It might not be obvious to the casual observer 👀 but there is a limit to how big and heavy speakers can be due to center of gravity issues. BUT those limitations don’t apply to subwoofers which have relatively low centers of gravity. So, springs can go directly under the sub without all the rigamarole needed (a la Townshend Iso device) to get the springs in a wide pattern so the speaker will be stable.