Why the voice matters
In the Liturgy, the people themselves answer, chant, and pray. The voice carries psalms, litanies, hymns, Gospel responses, and Communion praise. A simpler musical setting helps the words remain clear and keeps the service connected to the received Coptic rite.
The restrained sound also protects the difference between Eucharistic worship and other gatherings. The Liturgy has its own order, altar movements, priestly prayers, deaconal responses, and inherited melodies.
Instruments in other settings
Some parishes may use additional instruments in non-liturgical gatherings, youth meetings, retreats, or celebrations. The altar service follows a more restrained pattern because it is the Eucharistic worship of the Church.
This is a matter of rite and liturgical discipline. The Church receives a way of worship and teaches the faithful to pray within it, so the music of the Liturgy remains vocal, ordered, and recognizably Coptic.
The restraint also keeps the deaconal responses accessible. The faithful can hear the words, follow the tune, and answer with the Church in the musical form of the Coptic rite.