Assuming your Teac maintains greater than 8x across the entire disk, then that's really all it needs to do. Extraction is slowest at the beginning of the disk and typically increases gradually as the laser moves toward the outer edges of the disc. Therefore, if the 13x you mention is an average (arithmetic mean) of the read speed, then chances are it is reading at less than 8x near the beginning of the disk.
If I remember correctly, some people were able to achieve very good DAE with the Teac 32x, while others couldn't get much above 4x. If you haven't done so already, you can check your specific drive with Erik Deppe's very handy CDSpeed utility ...
http://www.come.to/cdspeed/ It will test and graphically display the drive's audio extraction rate so you can easily determine how well it's working at the beginning of a disc.
Best regards,
Floyd