There are many differences between live band classical and rock concerts. First and most important is you will hear music without any distortion in this environment as opposed to amplified rock music.
Since the concert is in a church, pay attention to the long reverberation of sound, i.e., slow decay of musical notes which adds more to your enjoyment. Do you know which Brandenberg concerto they will play? The second concerto has a most unusual solo ensemble consisting of trumpet, flute, oboe, and violin. Pay attention to the trumpet and its long decay of notes unlike you have heard elsewhere. Same goes to other instruments. Bach's third concerto may be the most popular concerto grosso ever written.
So you are in for a treat. Don't worry about imaging, layering, 3D sound-staging and other crazy stuff we pay attention to in our hi-fi audio systems. This is pure unamplified music. What you hear is the real thing. There is no comparison for this.