Seriously though, I have "frozen" tubes in the freezer for a few days just to see if they would sound better, and they do, everything becomes more focused, tighter, especially the bass with more punch as well. But it does not last forever, 2 weeks tops... I do not know if it had any lasting benefits at all with just using the freezer, but I believe a cryo treatment is a bit more permanent though I do not know what affects it has on the sound.