The jubilus to a mass alleluya is precisely what your quote from Augustine defines, though he wasn't in this instance speaking of said alleluya. The '-ya' (or '-ia') portion of 'alleluya' is, in fact, a form of God's name, 'Yahweh'. The jubilus, properly understood, is indeed a burst of joy, an ejaculation of gladsome delight in God himself and the holy gospel which is about to be read from. The loss of this jubilus in mass alleluyas in our churches in the post conciliar order is grievously lamentable. I'll not waste more words on the trite tripartite drivel that has replaced a genuine mass alleluya. We have been robbed..... yet again!
(And this, like so much else, was not mandated by the council but foisted off on us.)

And, let me add that so-called 'charismatics' do not have a monopoly on charisma!

...Charismatic musicians...

With no offense to Ruth Lapeyre....
Somehow, I don't think that that term is meant to apply to any of us. That is a mistake....

It happens from time to time that a person or group will snatch a label which would normally be a positive descriptor of any number of persons, things, or groups; will snatch it and rather monopolise it to the extent that its otherwise positive associations are forgotten or dropped as it becomes associated solely with said person or group. 'Charismatic' is one such descriptor. There are any number of persons and groups and things which are charismatic. We could name Benedict XVI, Gregorian chant, liturgy that resonates with historical precedent, our patrimonial music and its modern ('modern' as opposed to 'contemporary') progeny, certain priests, or choirmasters, or ordinary persons whom we might know, the enduring charism of certain saints or great minds, and on and on - even unnamed members of this our forum. Instead, 'charismatic' has come to mean that group of Christians (of various denominational persuasions) whose speech is peppered with predictable (very predictable!) 'charismatic' patois, whose liturgical praxis is defined by the impromptu emotional faculties, and who seem, typically, to believe that 'non-charismatics' are somehow the practitioners of an inferior spirituality.

Isn't it time that we thought of a better label for these folk, time that we refused to grant them a monopoly on charism and being charismatic? The entire Church is charismatic! Heaven help us if we aren't. We should assert that we are and leave so-called 'charismatics' to find another word for themselves, one that doesn't imply that they have a monopoly on charism - because they don't.

I rather think that charism is in a category similar to wisdom. No truly wise person would go about saying that he or she was wise. This is something recognised by others. The moment one would announce that one was wise we all would know that he or she wasn't.
Ditto charisma or being charismatic.

I want to thank you all for responding. Perhaps Charismatic musician is a poor term to use as the Charismatics who push the idea that the "jubilus" of the Alleluia is somehow a form of "tongues" are certainly not musicologists or even musicians as far as I can tell. These are quotes from a web site that espouses the idea that improvisation was pretty much the name of the game up until the 9th century. However it is my understanding that notion flies in the face of what the restorers of Gregorian Chant found when they compared the few manuscripts that survived. As I recall they found that there was quite a bit of similarity between the various Alleluias (indeed most of the Proper chants) from distant monasteries which supplied the Benedictines of Solesmes their sources for study and restoration.

Here are several quotes from a site called: https://www.worshiptraining.com/media/jubilation-in-the-patristic-era/

"The term jubilation has a wide range of meanings. Essentially it was understood as the spontaneous outward expression of inner spiritual experience. Such expression might come through wordless songs or sounds, but could also be manifested by bodily expressions such as gestures and laughter. As we survey what the church fathers have to say about it, we note references to three major types of jubilation. First, musical jubilation was a form of spontaneous, wordless singing. Second, congregational jubilation was musical jubilation in a liturgical setting. It was the custom of congregations to sing an alleluia before the reading of the gospel, and to extend the last “a” of the alleluia into a long, spontaneous, wordless song. Third, mystical jubilation was the flow of wordless sounds, musical or nonmusical, along with laughter and gestures, which accompanies intense spiritual experience."

And this:

"It was during the ninth century that improvisation of the jubilus ceased to be an expected part of the liturgy. From the period of Pope Gregory I (“the Great”) in the sixth century until the eleventh century, the church was in the process of absorbing new nations and barbarian tribes, often converting them en masse. While these were real conversions, it could take generations for a vital Christianity to filter down to the ordinary people. This situation inhibited the practice of improvisation, which relied to some extent on the spiritual sensitivity of congregations. Church music began to be performed more and more by trained choirs; this resulted in the writing of church music in notation, causing it to lose much of its improvised character."

Another "expert" in his book tries to make the connection between the early Church "jubilation" on vowels as being identical to what contemporary charismatics do which they describe as speaking or singing in "tongues".

https://www.amazon.com/Sounds-Wonder-Speaking-Catholic-Tradition/dp/080912002X/ref=asap_bc?ie=UTF8

Normally I would ignore what I consider spurious assumptions but this book in particular is being used as a source in a recent publication (indeed I'm not sure it has been published as yet) which makes the same connection.