Peri´s
Scope/Montreux II/Bill Evans/Jazz/1970
"Peri's Scope" is a perfect model to initiate a discussion of two-handed piano voicing principles that are root oriented. There are three rules or directions to follow:
1. Use the root third and seventh under the melody;
2. Omit the fifth of the chord;
3. For added, optional color, add a ninth, eleventh, or thirteenth
Observe in all of the examples that the root is always the bass note and above the root you place the third, seventh, and melody. The voice leading alternates—EX. 1: R (root), 3rd, 7th leading to R, 7th, l0th in measures 1 and 2; or R, l0th, 7th leading to R, 7th, l0th in measure 3— depending upon the root movement. In this tune the root movement is mostly down a fifth (or up a fourth, i.e. II-V, III-VI of measures 1 & 2). I call this the diatonic cycle of fifths, and since "Peri's Scope" does not modulate to another key, I rate it as a very imaginative diatonic composition for that reason. Bill had a composer's ear for variety and learned how to effectively use secondary dominants (see measures 7, 8,14,15,16 & 20). This makes Peri's Scope a challenge to the improviser. The challenge is unique because you meet the secondary dominants in different ways and in different parts of the phrase.
For example, in EX. 2 below, the IIIx (E secondary dominant seventh) lasts for two bars (7 &
8) and it's the climax of the first phrase of the tune. It's very sudden. It jumps out at us.