In response to complaints on various forums about how importing or playing some audio CDs results in distorted sound, Apple has issued an update to iTunes, now at version 10.5.2 which is said to fix the problem, as well as makes unspecified improvements to iTunes Match. The download is available for both Mac and Windows, the latter having separate 32- and 64-bit versions available.
The Mac download, which requires OS X 10.5 on either PowerPC or Intel Macs, comes in at 102MB. The 32-bit Windows version is 66.13MB, while the 64-bit version is 68.01MB. The update may take some time to roll out through Software Update but is available from Apple’s support website regardless.