While ripping audio CDs in the past few days I noticed that not all CDs can be read at top speed. My PX-708A can extract audio at up to 17-40X CAV, but some of my music CDs refuse to be read faster than 8X CLV.

(I only noticed this recently because I upgraded to a faster drive and switched from EAC to PlexTools. My old drive with EAC was slower than 8X so I never noticed variation between CDs.)

I know there are characteristics of CD-R/RW media that impose speed limitations, but I am surprised that some of my garden-variety pressed audio CDs have to be read quite slowly.

What exactly determines the top speed a pressed audio CD can be read?

Here's a thread where speed problems are being discussed : http://www.hydrogenaudio.org/forums/index....howtopic=19627&

This said, if your speed is indeed related to the CDs, it must come from their error rate in your drive. CDs with a high error rate will be read slower. It is also possible that there is a scratch at the beginning, and the drive slows down, then refuses, for a given reason, to speed up.

I'll follow up in the thread you referred to, but I question whether the CD reading speed "must come from [the] error rate." I understand your point, but just like a drive can select the appropriate burning speed for a blank CD-R by detecting the media type, it seems the same could be done for reading. Of course I had always assumed that all commercial audio CDs were pretty much identical, but I could be wrong.