Yes. Decoupling the base of your machine from whatever it’s sitting on can reduce noise levels by an audible amount. I got about -5 decibels by adding rubber feet to my machine. It’s not much, but should notice a small difference.
Pretty much any rubbery thing will work. Neoprene is commonly used, and cheap. The best vibration absorbing material is Sorbothane, but it’s very expensive. I used those standard solid-rubber feet that you can buy in hardware stores.
To decouple an entire enclosure, you need to line the interior of the box with a rubbery material and then add a hard layer over the rubber. The acoustic energy will vibrate the hard interior walls, which vibrates the rubber lining, which converts the mechanical energy to heat – thus mechanically decoupling the interior from the exterior.