Tried it. Now I think the idea that there is some orthopractical interpretation of these ancient neumes is a bunch of hooey. Because of that, they are perfect for our postmodern world, mixing subjectivism and traditionalism (into something hopefully workable and aesthetic). Like some forms of psychological warfare or ideology, the sheer gibberish of it all shocks and confuses the choir out of their autoplay mode. Because in crisis we look to authority for guidance, in such a state the choir is more likely to pay attention to the director, who is free to interpret any squiggle like a Rorschach blot without allowing an "akshully" from some neume nerd, because all interpretations are arguably valid. So net-net, it's a stress on the choir, but can produce better sound, if the director is good enough.

Interesting assessment, Chrism. I'm not sure that it holds up. Suppose in what you wrote, we replace "ancient neumes" with "square notes," and given the controversy surrounding interpretation even of square notes, I expect it should apply. What do you think?

I think it is another symptom of our text-centred, literalistic musical approach of the last few decades. The freedom of chant and subtleties of its interpretation cannot be re-created by sweating over the exact notation given in the manuscripts—trying to re-enact a certain interpretation is simply fallacious.

Antiquarianism : yes, they're antique.

Rigidity : only if the user insists on a single orthopraxis and anything else is wrong -- especially in cases more Rorschach than rastrum.

I have sung at Mass from the Triplex a few times. Including times when I couldn’t find my regular dog eared gradual but the nice crisp triplex was just there to hand... but more often on purpose.

I don't know the melodies well enough to sing from the chicken tracks adiastemic neumes alone. Nothing like. Well unless it's a requiem. So I experience them as elaborate, and rather useful, performance notes. Like performing from an annotated urtext.

Which is rather ironic, of course.

I guess I spent two weeks at Saint Meinrad some years ago studying a bunch of hooey with Fr Columba Kelly OSB, but I still find the Laon markings especially useful for emphasizing (the t or tenere mark) or moving lightly through (the e, which is really c, or celeriter mark) particular notes. I don't have to sing for Mass, though, and it would be a huge challenge for a parish schola to do all the markings. Fr Columba's overarching theme was that the chant should convey the text; he spent much of his career setting English texts to chants that work for English, with important adaptations from what would be done in the Latin. That's the message I got out of learning the Triplex markings, not that the chant must always be done with them.

Facts:
1. The Graduale Triplex is the 1908 Vatican edition arranged for the novus ordo.
2. The two volumes of the Graduale Novum are also Vatican editions, although lacking official recognition of all their content.
3. The Catholic Church ("Rome") has the authority to regulate liturgical music praxis, not musicological scholarship.
4. The Vatican edition was an imperfect restoration imposed on the Catholic Church by Rome and was not something that developed organically over the centuries.
5. When the Vatican edition was promulgated, it was intended to suppress the Medicaean editions, not the ancient manuscripts; the motu proprio of 1904 (not to be confused with TLS) even stated that other editions could be tolerated if "the variations introduced prove themselves to come from the authority of other good Gregorian codices."
6. The Solesmes rhythmic markings are not part of the Vatican edition and no one is required to observe them.

Probable opinions:
7. The ancient manuscripts have greater authority than Dom Mocquereau.
8. There are few if any in the Church hierarchy who really care whether or how Gregorian chant is sung nowadays.
9. Neumes that clearly differentiate long and short values cannot reasonably be considered "intentionally vague," as someone here put it.

As I understand it, antiquarianism with regard to the liturgy refers to a preference for older forms simply because of their antiquity, not necessarily because they're better suited per se, usually to the exclusion of forms that developed organically. A solid argument could be made the Vatican edition itself was a manifestation of antiquarianism, and that the Medicaean edition represented organic development. Indeed, we know there was considerable opposition to the restored editions.

Claiming that "the Church has assigned a text [i.e., a performing edition]. And that text is not the Sankt Gallen or Laon neumes" is a lazy way out of the debate. The Church also called for a more critical edition of the chant books to be prepared...almost six decades ago. I remain baffled as to how any musician interested in historically informed performance practice could be content with uncorrected ca. 115-year-old editions.

Dangerous Opinion:

All editions of the chants are good and useful.

In my time as DM, I have used the Solesmes edition, the Triplex, Gregor und Taube, the Sarum Gradual, the Cistercian Gradual, the Medicaea, Amiens, and Paris. Along with DuMont.

The Triplex probably best serves the director

Agreed. And that's even assuming the director knows what they are looking at.

I would never put the triplex in front of my choir apart from showing them a sample page one time to explain some of the musical choices and discuss chant scholarship as a mini history lesson. Precious few people actually know enough to make heads or tails of those symbols, so for the overwhelming majority they just clutter the page. Ultimately, the triplex is just the gradual with pictographic critical commentary. It's a work of scholarship rather than practical singing document. (And what is even more disappointing, is at least my copy is a crappy scan of the original—it's the real book, not some knockoff, but the reprints are not very high quality—so every page is fuzzy.)