Many reviews in What Hi-Fi refer to how the rack improves sound and picture. Does anyone know how this is the case and whether or not it makes a noticeable difference in a "real world" environment? Do you need a very high end system for the difference to be noticeable? I can understand how sound can be improved from the centre speaker as it is essentially being placed on a quality stand, however how is the electronic signal in the amp / player and monitor improved?