chord progressions

[buttersg]

Hi, I'm using Harmony Book B right now (the blue one).

Actually, I've been doing Grade 6 since forever .. but just can't get the harmony and chord progression understanding right ...

Based on the book, there are all the rules to using of chords. But are the chords actually restricted to only those listed in the book? Or is it flexible usage as long as the harmony sounds right?

eg.
Can chord VII only be used for the Ia - VIIb - Ib progression?
Must chord III be followed by VI in harmonic minor?
Is second inversions limited to I, IV, V?

And my friend commented I always like to start with a first inversion chord for cadences ... Is it alright to do that? Will it sound better with a root chord?

As a result of all the above, my harmony exercises are always playing around with I,IV,V,VI and their first inversions ... which is commented as boring 

[lelle]

Based on the book, there are all the rules to using of chords. But are the chords actually restricted to only those listed in the book? Or is it flexible usage as long as the harmony sounds right?

It always depends on what effect you're after. There are certain progressions that are tried and true (progressions along the circle of fifths, cadence, half cadence, etc) that composers manipulate and glue together in different ways to create music. One way to manipulate these are to do what is not expected (deceptive cadence for example) to get a surprise effect. When you know and understand the rules it will be easier to know and understand if and why the harmony sounds right

Can chord VII only be used for the Ia - VIIb - Ib progression?

No. For example, both in major and minor keys the VII is usually a diminished chord, so you write vii° (this illustrates it quite clearly: https://musictheory.alcorn.edu/Version2/theory1/Roman.htm) and it usually functions as a dominant, so it can be used anywhere to replace V7 (or V). In C major V is G major, and vii° is B-D-F which is exactly the same as a G major 7 without its root note G.

Must chord III be followed by VI in harmonic minor?

Not to my knowledge, why do you think so?

Is second inversions limited to I, IV, V?

Everything can be in any inversion (but it is very common to use specific inversions at specific times), it depends on where the music is going. For cadences you usually want to land on the root position or 1st inversion.

If you are interested in this stuff I recommend you look into function analysis https://en.wikipedia.org/wiki/Diatonic_function because I think it helps illuminate how things actually work (it's more advanced than roman numerals but it's a much better system in my opinion)

[mjedwards]

     I think it will depend on whether you are trying to pass theory exams or trying to compose a piece of music.  In the former case, you will do best to follow the rules you've been taught, and that you will be marked under; in the latter case, do what feels right, taking into account the overall effect you want in the piece, any stylistic conventions the piece follows, etc.
     Composers can get away with breaking rules if they do it right.  In Beethoven's Piano Sonata no. 9 in E major, Op. 10, no. 1, first movement, second subject, there is a consecutive perfect-5th violation.  It's extremely well hidden, and extremely difficult to find - but it's there, and it is completely unobjectionable.  I tried to find it a week or two ago, and it took a full 10 minutes or so of staring at the dozen or so bars where I knew it was before I could spot it.  Who knows whether Beethoven did it intentionally, or completely unconsciously, just because he knew what effect he wanted, and knew how to get it?  Once you're that good, you don't even have to think about rules of that sort - you just do what you want, and you know how to get it right.
     But it is probably true to say that you need to know the rules first, and *knowingly* break the rules once you are advanced enough in your skill to make that judgement, instead of accidentally breaking them through neglect or ignorance.  Once you know the rules thoroughly, you are in a better position to judge when you can get away (in composition) with breaking them, and when you can't.  So I would never use what I've said as an excuse to just not bother learning about "dull" rules.  Learn them, obey them in exercises, exams, etc.; then, if you wish to compose, you may be able to decide whether, in a particular case, you need be bound by them or not.

Regards, Michael.

[genosen]

Not to my knowledge, why do you think so?

I think he is referring to the V-i Cadence in the relative minor key.

Must chord III be followed by VI in harmonic minor?

In most cases, yes, although I've seen it followed by the IV chord, and other pre-dominant functions. I think it's helpful to think of the III chord as a V chord, and the vi as an i.
The degrees: vi - ii - III - vi correspond to degrees i - iv - V - i in the relative minor key. The chord progression is used in the same way as the I - IV - V - I progression. With the sub-dominant resolving into the dominant, and the dominant into the tonic usually via authentic cadence
Edit: Whoops! Just saw the date these were posted. My bad.