If the only accidental in Gregorian chant is B-flat then why is there two accidentals (flats) in this introit? On the other hand in the old days they used another tuning system so I don't know how the sang it back then but still this fact about only one accidentals appears all the time.
In quadratic notation (square notes, neumatic notation) this is written with an range of fa-fa' with one flat, te, which could be rendered as F-f with one flat, B-flat -- the Lydian mode on F (key sig. of C major); but it has been transposed for a more comfortable range with the range E-flat to e-flat. This is still fa-fa', but in B-flat rather than C, thus necessitating the use of the two-flat key signature, and the use of the A-flat accidental -- Lydian mode on E-flat (key sig. of B-flat major).
This is actually far less confusing than it seems.
It's actually a bit confusing when you learn facts and then see evidence that it's not even true. Gregorian chan does in fact use more than one accidental. Should I just forget this fact that I've been taught?
Your teachers were correct, but this isn't chant. It is a chant melody.
It's chant written out in modern notation with modern key signatures to lock it into one of two different levels.
Chant uses moveable DO and you get to choose what actual pitches DOis to fit the natural vocal range of your scola. In this case the person who wrote this out took that choice away from you and did it himself, locking it into a pitch range he felt was proper.
I can tell you some things that will help immeasurably:
1) If you do not read quadratic notation (square notes, Gregorian notation) learn - it's not difficult at all.
2) Learn about modal music theory from a chant-based perspective. Get away from major/minor and the rest of that common practice mumbo-jumbo, the modes are more interesting anyway.
3) Find a good teacher/mentor who can help you and answer any of your questions, depending on where you are, there may even be one of us on the Forum that could help you. I have heard people who try to teach themselves chant just by reading the preface to the Liber and going for it, and somehow it always misses. The chant is a living thing, like an aural history, that needs to be passed down from person to person.
4) (Maybe more of a '3a') Go to a CMAA Colloquium or Chant Intensive. If you are out-side the States, don't worry, there seem to be more of these kinds of seminars popping up in various countries. But go to something where you can be immersed in the chant and live and breathe the chant for some length of time, be it a week or just a weekend.
I think you're confusing sharps and flats with accidentals. Strictly speaking, accidentals are notes not included in the key signature; if your introit were transposed to begin on G, with 2 sharps in the key signature, c-natural would be the only accidental.
I see, the problem is that this introit is written in modern sheet music and not in Gregorian notation. Did I understand you correctly? You told me to find a teacher. I live in Sweden and I don't know where to find that awesome treasure!
Fascinating! Where in Sweden do you live? To find a teacher of chant, you might enquire at a university music department, you might try the choirmaster at your nearest cathedral or major church, you might try a monastery or two. If these can't help you they might point you in the right direction. I think that the university at Gottingen might have some helpful faculty.
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