I think it's a bit situational. We once had someone visit our parish who was a trained singer and was just passing through. She could have nearly functioned as cantor without a microphone because she was so loud. It was clear that she was a highly trained singer and was just projecting in keeping with her skills and training, not "showing off". I was pleased to hear her singing, although I think as a matter of personal prudence it might have been appropriate for her to turn it down a bit. A sort of, "read the room" situation. At least in this instance, I don't think it was showboating, much like I don't think I'm showboating when I sing out at other churches (and am often alone in doing so). But I also don't try to compete with the cantor, especially if everyone around me is very quiet.

There ARE people who do make a habit of showboating, however, and that is clearly inappropriate, regardless of skill level.

There are people who in so many words effectively think Catholics in the pews should sing but rather feebly and not be audible more than 2-3 feet away. They are a legacy of generations of discouragement of singing. Handicap their opinions accordingly.

IF you're musically and vocally competent, sit yourself halfway to two-thirds of the way back into the main worship space where your voice will best be blended by the acoustic and sing musically and competently. A supporting voice, not a leading voice.

and carpets surely do not help! I recall singing in a 1990s newly constructed church which was carpeted throughout the pews. You could not hear the person on either side of you! All you could hear was your own voice. I believe it is a fact that most of the pips will not sing unless they hear singing from those located nearby in the congregation.

"Would you like to join our choir?"

The best answer to that often is: you need more voices in the pews, not in the choir.

See https://forum.musicasacra.com/forum/discussion/16728/on-the-lighter-side#Item_63

I've often said that we should turn our schools into prisons, and build real schools.

Is this parish you're describing a converted Jesuit retreat center OR psychologist's office?

In my parish the choir has only been singing on major feast days. It would seem that Corpus Christi does not rate high enough this year for the choir to sing. When times like this occur, I'm in the pews and I can tell you about the only time everyone in the congregation is actively participating or singing is when when we sing/chant the Lords Prayer otherwise they don't sing or they sing to themselves. I thought about why this was and came to the conclusion that the Lord's prayer is probably the only piece of music that never changes from one week to the next.

There are other factors at work in my parish that create or that foster non-compliance by the congregation especially when it comes to singing, everyweek a different Entrance and Communion antiphon, Responsorial Psalms and about every three months or maybe five a different gospel alleluia or Mass setting. Also, when the cantor sings it is not whats in the pew missal. Kind a hard to follow along or participate when the philosophy is "Oh they've heard this before, or we sung this before so they'll know it"

I only bring this up because as a choir member in the pew, our congregation isn't singing and have to believe this is the case in many parishes. This may not make any sense but when I was growing up and when I first joined the choir forty some years ago, we had one Mass setting, one Alleluia setting, traditional hymns that people knew and what was in the missallette is what the choir or cantor sang.

Today it seems that we need to keep the congregation guessing and then question why they are not singing. Some food for thought.

To add to what Sponsa says, it is also possible to do both hymns and propers. For instance, today we will sing an entrance hymn whose text is a trope of the entrance antiphon, and once the priest reaches the altar, the hymn ends and the schola begins chanting the introit. We invert the pattern at communion, where we first chant the communion antiphon, then sing a choral motet/anthem, and lastly sing a communion hymn as communion is finishing and purification of the sacred vessels takes place.

Re: the hymn and introit thing, I'm not going to tell people what to do, but as a PIP when it comes to the NO, on the rare occasions these days that I attend it, I'd rather just do the introit, which is what the book envisions, and then choose one really spectacular hymn on the way out. And for communion, I would like to see restored, one of these days, the practice of singing the Communion chant at the purification; in our parish, we do it after the triple recitation of "Domine, non sum dignus" (TLM…) and it's either very long, leaving us no time for anything else, or we have to sing at least one hymn (sometimes repeating it), because it's so short. Now, normally, and in fairness, the organ plays when permitted, which is a relief; this is all to say that singing at communion beyond what's required is something that I loathe with very few exceptions (one of them being, surpisingly a good version of "I am the Bread of Life," the Proulx arrangement of which is excellent).