The role of diminished chords in classical music…

[Chevereaux]

So.

This month I began, for the first time, to try to compose, this time with the aid of at least one resource which provided me with some basic guidelines for composing. Thanks to this awesome site, I bought the book Composing: A New Approach by William Russo.

I’m only on page 30 or such, but already I’ve learned lots and lots of stuff that I see are applied on classical pieces from the 1750s to the 1850s (Beethoven and Chopin, mainly).

The book doesn’t cover progressions dealing with diminished chords, though.

You know how the Locrian mode is a diatonic scale of C major (or any major/ionian scale, for that matter)?

Does this mean that, 1) a diminished chord, can move freely among ANY type of diatonic chord (major or minor), and 2) the diminished chord can move to any nondiatonic chord (major, minor, or diminished)?

I guess if all else failed I’d use the basic rule of thumb: If it sounds good, then it most likely is good. If it doesn’t, you need to change it.

By the way, I’m new here, nice forums! Needs more people though.

[fontadoni]

I agree, we need more people posting in here.

I had a composition teacher that always said that if you wanted to learn harmony, you should buy yourself a copy of the Bach Harmonized Chorales. He said one should sit down and play the chorales on the piano and analyze them, sing them, and know them well.

Everybody knows that Bach was the great counterpoint and chorale master, so why go a different way. This has proven to be invaluable to me.

However for analyzing and understanding Bach, one must at least poses a basic knowledge of harmony, so it’s good to know that you are trying to read and teach yourself about it. A book I could recommend to you would be: "Harmony & Voice Leading" by Aldwell & Schachter. I think this is a very decent book because it makes emphasis on real music, specially the music of Bach. Some theory books tend to divide the theory from the real music, so whatever you learn ends up being useless.

About your question regarding the role of the diminish chord:

In what they call "the common practice period", the chord built on the 7th scale degree of a minor key is a fully diminished 7th chord. Fully diminished 7th chords are unstable and have a dominant function, meaning that they always want to resolve to the tonic of the key.

In major keys, the chord built on the 7th degree of the scale is a half diminish chord (has a minor 7th instead of a diminish 7th) and has the same dominant function. These leading-tone 7th chords as they usually call them are interchangeable with dominant 7th chords because they share common tones, both in major and minor keys.

It’s important to note that in minor keys, the chord built on the second scale degree is a half diminish chord as well, but in this case has a predominant function, mainly because it does not have the leading tone of the scale in it (7th scale degree), so it does not create that tension that wants to resolve to one. This chord was frequently used in first inversion (with the 3rd of the chord in the bass) to avoid the tritone or augmented fourth relationship with the bass, that was considered to be dissonant.

It’s always good to remember that the bass in most cases, tells you the function of the chord.

Hope this helps.

[Chevereaux]

I was just putting to practice what you said, and it seems that fully diminished chords interchange more accordingly with minor chords, while half diminished chords interchange better with major chords.

Awesome!

And those books look great. I’m thinking of buying the Bach one, and perhaps the harmony one (if I can get the cash ).

Thanks, your post was definitely of great help to me.

[CaseyDoddMusic]

Something to look into as well is the use of Secondary Diminished Seventh chords. Just like Secondary Dominant chords can spice up your writing and lead you into some undiscovered terrain, Secondary Diminished Seventh chords can lead you into some different resolutions that might spur your imagination.

[Author]

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