1. The antiphon from the Roman Missal as set to music there or in another musical setting;
2. The seasonal antiphon and psalm from the Simple Gradual;
3. A song from another approved collection of psalms and antiphons;
4. Another suitable song.
Almost all churches in the US consistently use option 4: another suitable song, when the preferred option 1 is the chanted antiphon! There is a compromise to be made between the preferred Gregorian Chant and any other song, and we have found these in Christoph Tietze’s Introit Hymns for the Church Year. This is an excellent collection of the Entrance Antiphons that are set to popular hymn tunes. We have been using these here for quite some time now. Whenever you see a Latin title for the Entrance Antiphon, know that we are singing the preferred text for the Entrance of the Mass, coupled with a psalm and doxology (a blessing which invokes the Holy Trinity).
(Originally appeared in Christ, Prince of Peace Bulletin, 11/14/2010)