Jay Knowing and understanding all these parameter doesn't necessarily help when you have an undocumented reel in your hands! A lot of material in public archives & libraries lacks such technical information. I have found a useful tool for determining what tracks have been recorded onto a tape is a Group Arnold Magnetic Viewer 1022. This responds to the magnetic fields on a tape and gives a visual representation of the recorded track pattern on a tape. Nigel ---------------------------------------------- Nigel Champion Archive of Maori & Pacific Music The University of Auckland Auckland New Zealand