bought dvds appear to play fast

bought season 3 of Monk off Amazon (region 2), however upon playing them on a region free machine (philips 642) player, they seem to play too fast.
i.e., the voices sound like chipmunks...

ripped with dvdshrink, to remove region coding, and played the rips on another dvd player (LG) and yet exactly the same problem.

any thoughts - are the discs faulty or what? - have never heard of this issue before.
cheers for any advice...