It's the annual Christmas season, and a superb piece to play back on a full system is Bach's Christmas Oratorio BWV 248. Many recs of this. The one track that I really come back to is the soprano aria in Part IV:
Flosst, mein Heiland, flosst dein Namen. There is an
echo in this track, with a second soprano positioned at a distance to mimick the echo. Gorgeous, really. It's a perfect test track, to convince me that my speakers and gear are well calibrated to give a deep soundstage (they are

).
Buy it here as a single track (scroll down to Part IV,
Flosst, mein Heiland, flosst dein Namen):
https://www.prestomusic.com/classical/products/8030053--bach-j-s-christmas-oratorio-bwv248cheers