I still have not figured out why I perceive foobar to sound better than iTunes
I was just playing with Foobar 2K and I don't know if this might be the reason that it's perceived to have a better sound than iTunes...
under Library on the main menu, click on Configure and under Playback, you will see that by default they apply a
Replay Gain to the playback of the music which is probably why it sounds different. You can turn it off if you want and see if you notice a difference.
In iTunes (11, for me), I see this as an option you can turn on under Preferences called
Sound Check. It sounds like the same thing but I don't know if it will make it sound the same since I have never used this feature.
Just an assumption.
"ReplayGain is the name of a technique invented to achieve the same perceived playback loudness of audio files. It defines an algorithm to measure the
perceived loudness of audio data.
ReplayGain allows the loudness of each song within a collection of songs to be consistent. This is called 'Track Gain' (or 'Radio Gain' in earlier parlance). It also allows the loudness of a specific sub-collection (an "album") to be consistent with the rest of the collection, while allowing the dynamics from song to song on the album to remain intact. This is called 'Album Gain' (or 'Audiophile Gain' in earlier parlance). This is especially important when listening to classical music albums, because quiet tracks need to remain a certain degree quieter than the louder ones.
ReplayGain is different from
peak normalization. Peak normalization merely ensures that the peak amplitude reaches a certain level. This does not ensure equal loudness. The ReplayGain technique measures the
effective power of the waveform (i.e. the RMS power after applying an "equal loudness contour"), and then adjusts the amplitude of the waveform accordingly. The result is that Replay Gained waveforms are usually more uniformly amplified than peak-normalized waveforms."
~Wiki