[PIANO MUSIC] Today we're going to discuss
one scale in particular. We've seen it before as
the Lydian flat 7 scale when we've been using it
in the context of a chord scale for substitute dominants. We're going to talk about it
today as a primary scale which is used to create passages
of music all on its own. Sometimes the Lydian
flat 7 scale is referred to as the acoustic scale,
because the notes of this scale are actually transpositions
of the overtone series up to a high degree of
the audible partials. So why don't we just lay
that out for a moment? In the overtone series we
have the low fundamental. [PIANO PLAYING] Then the second partial
is the octave above. Above that we have the fifth,
then another octave, then a third. And then we start to get into this
sort of raised 4 territory, up to the flat 7. So you get this kind
of floating open sound. It's the sound of the overtone series. When we transpose that down
into scale form, we get this. [PIANO PLAYING] Again, I'm just letting
that ring so that you can hear what a beautiful, rich,
mysterious beautiful sound that is. And the C acoustic scale is interesting
in that it has attributes of two modes that we've studied before. It has attributes of the Lydian. [PIANO PLAYING] So it's first four notes or
tetrachords are the Lydian tetrachord. [PIANO PLAYING] Whole step, whole step, whole step. And it's second tetrachord or four
notes is that of the minor scale. [PIANO PLAYING] Whole step, half step, whole step. So in a way, this is-- if we
think about this like a mode, we actually have two
characteristic notes. We have the sharp 4-- [PIANO PLAYING] --of Lydian, and the
flat 7 of Mixolydian, which gives us a lot
of rich possibilities. I'm going to just take a moment right
now and improvise some music for you in the C acoustic scale so that
you can see some of the potential. [PIANO PLAYING] Lovely floating quality isn't it? It's almost a mystical sound. In fact the Russian composer Alexander
Scriabin created a chord based on this scale that I've been playing-- [PIANO PLAYING] --which he called the mystic chord. You'll notice that as
I improvised for you, I was just simply using
the tones of that scale, arpeggiating them in different ways,
playing them in scalar fashion, creating harmonies that were based
on the tonic triad, created variety by moving to the 5 chord or
the 2 chord, which contained the characteristic note of Mixolydian
and the characteristic note of Lydian. Has a lot of potential. But basically it's a very
consonant, free floating sound that just allows you to create a
gorgeous, glorious, soaring mood.
