Originally Posted By: Mark Hayes
Originally Posted By: dcuny
For a non-counterpoint example of the same phenomena, consider writing for 4 horns in a jazz setting. If you've got a chord progression like:

      C | Am7 | F | G7 | C

You've got a mixture of 3-note chords (C, F) and 4-note chords (Am7, G7). If you double one of the notes on the 3-note chord so there are enough notes to give the 4 horns, you risk getting the same sort of "collapse" when the notes in octaves blend together.

To avoid this, you'll typically write all the chords out as 4-note chords, so the harmony maintains the same 4-note texture throughout:

      C6 | Am7 | Fmaj7 | G7 | Cmaj7


David,

I've lately (since acquiring BIAB, in fact) been wondering about the whole "jazz chords" thing, as in, why should it be part of a musical style to add "extra" notes like this? What is the point of turning every CMaj into a C6 or worse? Why complicate things for the sake of complication? Is part of it just to show off on stage, and look smart on paper?

Now I'm wondering if what you just presented might be part of the answer.

Something about the effect of chordal density on the perception of melody?

Now I'm going to be thinking about this all day. I should start with checking out that URL, thanks!

Mark

It's certainly a part of the answer. When improvising, it's a means to guide the other musicians about the structure of the sound and the direction it'll take, so that the soloist has a fairly clear route over those chords. If the backing musicians go too far "off piste" they can potentially clash badly with the soloist. With something like a big-band, it's pretty much essential to avoid a mad cacophony.

But it's also often a means to get a particular sound ... 6/9 chords for example, or m11.

Sometimes, for sure, it's showing off, though I think most showing off, when it happens, is done else-wise in the music.

Jazz relative beginner, starting at a much older age than was helpful.
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