I was going to wait awhile before posting about the sound upgrade. Yes, there is an improvement. It is subtle but definite in the bass guitar reproduction. Hard to say exactly what but it seems like the bass guitar has better separation from the rest on the music. If that makes any sense. I would say the separation is more on par with the midrange now. One disclaimer though, I recently changed receivers to an HK 3490. I only had about five hours of listening before adding the feet. I did notice immediately after adding the feet however.