Sorbothane is a material like any other, and it must be used in the right place in the right way. That means engineering calculations. The sorbothane website is a good place to start.
IMO, feet are not the right place. Spikes give much better performance in both the TT which form my testbeds - sound is more focussed and precise, while sorbothane feet sound mushy.
Where sorbothane shines is in motor isolation. But again, it's not often used correctly. According to the website, you need inches of low durometer material to isolate the typical AC TT motor. That describes my DIY units - but not many others. Of course, there are other valid approaches, like SME.
The key here is how much noise is transmitted into the TT plinth from the floor. If you live in a railroad switch yard, you will need as much isolation as you can get. The SME solution is made for you. IMO. If you live on rock, miles from the nearest industry, highway or railway, you probably don't need any isolation at all. The latter is my situation, which is why spikes without any isolation device work for me.
As noted, YMMV.
IMO, feet are not the right place. Spikes give much better performance in both the TT which form my testbeds - sound is more focussed and precise, while sorbothane feet sound mushy.
Where sorbothane shines is in motor isolation. But again, it's not often used correctly. According to the website, you need inches of low durometer material to isolate the typical AC TT motor. That describes my DIY units - but not many others. Of course, there are other valid approaches, like SME.
The key here is how much noise is transmitted into the TT plinth from the floor. If you live in a railroad switch yard, you will need as much isolation as you can get. The SME solution is made for you. IMO. If you live on rock, miles from the nearest industry, highway or railway, you probably don't need any isolation at all. The latter is my situation, which is why spikes without any isolation device work for me.
As noted, YMMV.