In our Church meetings (I am assuming you are speaking about Sunday services) prelude music is welcome and we usually try to use Church hymns or Church related songs to bring the Spirit into the meeting. I am aware of the beautiful pieces of classical music that also bring the Spirit in many ways, but I believe that because of the importance of the Sacrament and its meaning, we usually use hymns that may help us to remember the Atonement Sacrifice of our Lord and Savior Jesus Christ.