Yeah, it's time for some orchestral music in the Zelda universe. Twilight Princess' soundtrack sound quality was a bit iffy due to its use of MIDI.
For example, here's Midna's lament in Twilight Princess (MIDI):
And here it again, but as part of Brawl's soundtrack (Orchestral):
I dunno, I don't really know much about MIDI, so maybe it's just the quality of the recorded video on youtube. All I know is that the use of MIDI was one of the complaints in many TP reviews.