iTunes
To obtain bit perfect playback;
Disable all DSP like "Crossfade songs", "Sound Enhancer" and "Sound Check"
Disable the equalizer
If you use an outboard DAC over Toslink or USB; set volume to max
Source: krmathis
FLAC
Just like Microsoft, Apple don’t support FLAC.
You can install Fluke to import FLAC in iTunes.
You can use software provided by Xiph.
A detailed description can be found here.
© Vincent Kars February 2011