1. A system for adjusting the operation of a media-playing set comprising: (a) a display and a control item viewable on said display, said control item being adjustable between different settings for adjusting the operational characteristics of said set; (b) memory to store a test sample for said control item; and (c) a demonstrational tool to generate a plurality of preview items for simultaneous presentation on said display during adjustment of said control item, said preview items being based on said test sample such that each preview item reflects the effect on said test sample caused by selection of a respective setting for said control item.