I can't speak for AAA titles on the PS4, but what I do know is that many smaller games (in general, regardless of console/PC) have pretty mediocre sound quality.
There are several instances where the soundtrack in FLAC has been several times as big as the whole game. It's such a shame that it is like this.
On the Playstation 1, for instance, most of the size was from the music itself, with the game only taking up maybe 100 mByte.
Audio Gear: Sennheiser HD 800 & HD 650, SPL Phonitor, Abrahamsen V6.0 DAC, JBL 705Ps.