Always wondered about that whole break-in time thing. My only observation regarding sound is how to explain the times you walk in a room and know the sound is correct within ten seconds. How does that phenomenon square with the phsycoacoustic changing memory theory? If that was absolute then you would have to adapt to every system you were exposed too; and do it every time you spend a few days listening to something else as that something else would sound odd to you until it re-integrated with your aural memory based on this hypothesis. Yet people can remmember instantly the sound of systems they owned twenty years ago. Try walking into a room with a Pioneer reciever and a pair of Large Advents;.. even if you don't see the equipment, You get that instantaneous flashback; knowing immediately what that sound is. How could you remmember that if your aural memory changed so thoroughly? I think people who ascribe to this theory ignore the minds capability of processing vast quantities of data intuitively. We who believe there is a period of adaptation disregard exactly how the mind empirically processes information; we look at it as if the brain was a computor; which it most certainly is not and does not process in a linear fashion like machines.