OK... I'm back home from my appointment.
Here's the kicker,
@fabiocz , you are dealing with two different energies, and whether or not you can tame them.
Spoiler: You Cannot. Hedge: do so, completely.
I mentioned above: just short of turning your Sub down,
you will never be able to stop the Wave Fronts... the Acoustic Energy generated by the Driver... from vibrating things. NEVER.
There is, and I believe this even if refuted by others, a physical transference of energy conducted from cabinet to structure, even in the most well built cabinet. Depending on your structure and other such issues, this energy can affect the space you are in, i.e. create rattles or other structural vibrations.
For me, where I live has suspended wood flooring, and when built, I assume the landlord cut corners by either using a more widely spaced floor joist or thinner floorboard than is normally used. My room is effectively a wooden trampoline. When I walk across the floor, things move, no matter how light my step. My Subwoofers did rattle things, and this persisted largely, to some degree or another, until I finished a Coupling/Decoupling system.
Most will say carpet decouples, but to what extent? (Not much!)
Rubber feet (standard equipped) are supposed to help, but again, to what extent? (Still not much.)
Spikes couple, they do not decouple as is often advertised... they are meant to penetrate carpet and sit directly on the floorboard. (Using spikes on hard flooring, with discs, is pointless to a large extent, as they still act as a coupling mechanism (which is great for leveling, anchoring; not so much for dampening vibrations.)
The way I came to really understand things is that the balance of coupling and decoupling is necessary to achieve the best isolation. A solid pad with vibration dampening properties (think Maple Amp Stands (thick cutting boards) or Granite Slabs coupled directly to the floor) gives you this foundation. Spikes by themselves will still transmit energy, but by combining them with a material that naturally dampens that energy, you gain an edge. Then, you decouple on top of that.
For me this is a spiked concrete platform driven through my carpet to the floorboard, leveled, then my bass cabinets with Soundpath feet placed on top.
I would say I conservatively eliminated about 85% of the transferred physical energy as opposed to just using any one component on their own. Most of the rattles and vibration I would feel went away... not all, but most.
Yet strong LF content will break this isolation, not because of conductive energy, but because of the acoustic energy... the wavefront coming from the driver.
All of this is a prelude to asking you to really consider what your situation is. IMO, the Soundpath feet are a really good, if slightly overpriced, product. Those squidgy fcukers do wonders!
But you cannot expect them to do everything!
That said, I do not believe at all that the vibrapods can do better. Frankly, I would expect them to be less effective than the Soundpath feet for the simple reason as they do not have the mass to do what the Soundpath feet have demonstrated to be capable of.
Now, I find myself needing to (potentially) disabuse you of what I consider to be a pure BS marketing claim: None of these products will make your Bass performance "tighter" or whatnot, if that is what you are hoping for. Keep in mind, the Bass Cabinet (consisting of at least one Woofer and an enclosure is a complex system onto itself, and the interaction of the Driver in that Cabinet is not going to be affected by a set of feet. The Sub will either have good performance or not.
All these products aim to do (realistically) is prevent conductive physical energy from transferring from Cabinet to Structure.
If you have a poorly designed Sub that outputs a distorted signal, the distortions in the wavefronts will still cause problems. If you have a very clean and linear Sub that is capable of producing infrasonic frequencies, you will still have vibrations carried through the wavefronts themselves.
I hope this all makes sense to you.
