#1
It's been quite a while since I posted anything on U-G and thought it would be fun to jump back into these churning waters. I had to laugh after reading some of the threads containing the term "tetrachord" so, for what it's worth, here are a few of my observations on this topic...

Everyone reading this post probably knows that the major scale consists of seven consecutive tones, with an eighth tone duplicating the first tone at the interval of an octave. The intervals separating these tones appear in this sequence:
  • whole-step
  • whole-step
  • half-step
  • whole-step
  • whole-step
  • whole-step
  • half-step

A closer look reveals that the sequences identified by numbers 1-3 and 5-7 are identical:
  • whole-step
  • whole-step
  • half-step


Let's call the four tones defined by this sequence a major tetrachord. We can now clearly see that what we call the major scale can also be thought of as two major tetrachords separated by the interval of a whole-step. This alternative view has important implications for our understanding of key signatures and the Circle of Fifths.

to be continued in Part 2...
All things are difficult before they are easy.
- Dr. Thomas Fuller (British physician, 1654-1734)
Quote by Freepower
For everything you need to know - gpb0216.
#2
Cool thread! I remember how studying Ron Miller's Modal Jazz composition and learning about this tetrachords and how they construct the modes really changed the way i looked at the scales and how it could be applied in more musical way.
I'm looking forward to the part 2.