SVS SoundPath Subwoofer Isolation Feet

At that price, maybe you get what you pay for?  Seriously,  how much engineering and materials can go into any product that sells for $10 per unit ?

Springs are better isolation.  Much better.

@mitch2 If they were so successful why change the hardness of the rubber so much?  So which product do they stand by?

You nailed it exactly. You can not isolate a subwoofer. Bass is extremely powerful. Play a 30 Hz test tone at 80 dB and walk around you house, go outside and walk around your house. The whole house will be rattling. Glasses on shelves, silverware in drawers, the walls, everything will be rattling, a symphony of rattles. And, there is absolutely nothing you can do to stop it. Fortunately, the loudest sound always wins and with the entire system playing the rattling is masked. Anything that is not masked is usually easy to find and stop. (like my movie screen) 

@dtximages 

My expectation is very low when buying products that drastically undercut the price of the main players.  If I want a good product I never buy the cheap product.  I might not buy the most expensive product either.  Also, in this time of supply issues, a lot of the junk Chinese products as well as high quality products need to source components based on availability.  For a product like the one you discusses, the main/only driver in sourcing components is price.