My thanks to Marco for calling my attention to this thread today (june 19). In fact a few days ago I received a note from someone else at CD Freaks questioning that same statement on my CDMedia site (http://www.chipchapin.com/CDMedia/cdr4.php3).
I had sent the following response, which may be of general interest. I’ve added a few edits for clarity.
Thank you for writing, I appreciate your comments. As I’m sure you noticed, this was a direct quote [from a Richard Whitworth article in Tape Disc Business] in one of the areas where I hadn’t done any analysis of my own.
[But] my interpretation of the offending sentence is as follows:
- Nominal 1x linear velocity (i.e. the linear velocity at which the wobble is at 22.05kHz) can vary between discs, and
- The start and ending points of certain disc regions are physically fixed in terms of diameter
Therefore the “ATIP time” [i.e. the nominal duration as defined by the wobble] of those fixed regions cannot itself be fixed.
This seems plausible to me, but I claim no personal expertise in the area. Any elucidation on your part will be more than welcome.
I never received a reply, but having now read this thread, this still seems quite reasonable to me.
By the way I’m looking forward to browsing this site some more. I think this is the first time I’ve been here and it seems like a great resource.
Also, by all means send me any corrections or clarifications regarding material on my CD Media pages. I’m planning to do an update sometime this summer.