PS
Don't get confused by the bitmapping option for cd's. Details for the different options are below.
Off - Have a Guess? Disable bitmapping
Type 1
Set to use a technique called “dithering” to reduce noise or distortion produced during audio output
Type 2
Set to use a technique called “noise shaping” to reduce noise in the audible range
Type 3
Set to use a special dithering technique developed specifically for the PS3 system to enhance audio playback
I'm told type 3 is about the most effective for most playback sources, but there's no harm in trying out all settings with a good source and see what your own ears think
(When playing audio CDs, these functions are available only when audio is being output at a frequency of 88.2 kHz or 176.4 kHz. Set [Audio CD Output Frequency] under (Settings) > (Music Settings) to [44.1 / 88.2 / 176.4 kHz]. )