Hi guys,
My more than 2 cents worth (but not much more...) on this discussion:
I am talking from personal experience, the experience of colleagues known to me personally and whom I respect, and plenty of music history and biographies of the greats (not Wikipedia pages).
I can hear the level of schooling and music knowledge within seconds in somebody's music (under a minute if it is a really slow track). This is not an extraordinary ability. Everybody with the same schooling and knowledge as me or higher can do as well or a lot better. It is as simple as that. Seasoned professors (or great and learned ears) will even hear disparities in correct harmonic procedures. I am not talking about parallel 5ths and 8ves, something that every unschooled person brings up as an example in order to dismiss theory by citing composers that flouted this particular rule... There are so many conventions! And would you follow the German or the French school regarding them, for example?
Music Theory is not the be all and end all in art-music composition but it is a study of its own, with its own Bachelors, Masters degrees, etc. It does not merely form a part of an instrumentalist's or a composer's studies. I say to those who diss music theory - because they never studied it to an advanced degree; I personally don't know anybody that knows theory to ridicule it - have you noticed that most (if not all) great composers knew theory backwards before deliberately eschewing some of its rules? Ergo, methodically eschewing them? Ergo, not simply making inadvertent errors?
And I say to those who say -laughably- that learning theory is useless as it dampens the imagination: Is your music freer and more imaginative than the music of Mozart, Beethoven, Chopin, Wagner, Debussy, Strauss, Stravinsky, Prokofiev, Schoenberg, Lutoslawcki, Penderecki, Schnittke? By the way, if you want to ascertain how much theory you know (ballpark experiment of course), listen to Mozart's Musical Joke -use the score too- and see if you can discover all the places where you are supposed to laugh, and why. That work was composed by the great man for the entertainment of connoisseurs. A lay audience (= those who don't know music theory) would take it as a normal piece of music save for knowing the title and a few very crude passages.
Now, as to which music theory to learn in order to compose. Macker referred to a few great but antiquated manuals. He also said that he is very much interested in intonation issues. If that is the case, manuals contextualising musical conventions from the Gregorian to Baroque eras would be useful, but I would suggest more recent ones that incorporate the information found in those classics. For those who wish to write equal-tempered music, tonal or atonal, they should learn theory that applies to Bach's music onwards.
Like any serious skill, music theory cannot be acquired by watching a few videos, no matter what those videos claim. It takes years, and it took years for the aforementioned geniuses, for they didn't just learn I-IV-V-I with all the 7ths, 13ths and sus4s included. Plus, it is not a skill that you can learn by yourself. You can read and memorise all you want. If you don't put that knowledge to the test by harmonising Bach chorales, composing inventions, canons, fugues, sonatas, etc. and have somebody look them over, you are wasting your time! It is yours to waste of course.
Will knowledge of music theory (university level) make you a great composer? Please...
Will knowledge of music theory (university level) make you a better composer? Infinitely.
At this belated point, I must confess that I personally HATED studying Music Theory almost as much as I HATED Analysis assignments.
Do I use theory when I compose? Do you mean do I comb my scores for all the rules of harmony?... Do you actually know how many there are?! Are you asking me whether I look through an entire work to see whether my upward leaps of major 7ths in the bass are resolved correctly, or whether I have any downward such leaps, which are not allowed unless there is at least one other note in between (it might actually be the other way around, I don't remember anymore...)?
Are you serious?
However, I am not Brahms, am I? Let's compare our scores to his and see who has the most mistakes, and how many more... (Let's not actually)
As with languages, it all has to do with sum of knowledge and fluency, which comes from practice as well as talent.
You might say that such considerations are ludicrous when one writes at an advanced chromatic idiom. Well, yes and no. Somehow, composers that know their theory (theory that does not apply to their harmonic systems), they still write better sounding music. Better balanced. Better voiced. You see, theory was determined by compositional conventions that most talented musicians more than less agreed on. They agreed that music sounded better that way, and it seems to be the case. Somehow, proficiency in this knowledge transposes favourably to more advanced harmonic systems, and Schoenberg insisted upon very sound traditional theoretical training for his students, even though he was the proponent of a compositional system that had nothing in common with classical theory. He "threw" John Cage out of his class because he realised the man had no interest and/or capacity for harmony. And Cage found a way to not need it. But he barely composed for instruments as we know them, did he?..
P.S.: Thomas AdĂšs, Macker? Why? What possessed you?