-----Original Message----- From George Brock-Nannestad: :"...what are the deviations in measurements on the same disc, same diagnostic system, but different placement of the CD on the hub..." My experience with PlexTools has been they are remarkably consistent even after printing on the disk. Bob Olhsson Audio Mastery, Nashville TN Mastering, Audio for Picture, Mix Evaluation and Quality Control Over 40 years making people sound better than they ever imagined! 615.385.8051 http://www.hyperback.com