186 THE 7 NOTES 2ND HARMONIC SCALE OF 3 OCTAVES AND THE CORRESPONDING TUNING OF STRING INSTRUMENTS

This 7-notes scale is of course the


B1-E2-A2-D3-G3-C4-F4-B4

and its span is 3 octaves when closing back to F.

The CONTRABASS , GUITAR BASS, PUERTO RICAN CUATRO etc are tuned in segments of this scale.

E.g. The Puerto Rican Cuatro has tuning


B3 B2♦E4 E3♦A3 A3♦D4 D4♦G4 G4

This tuning allows rather symmetric  representation also of the melodic-2nd harmonic 11-notes 4-octaves scale (of chords) as in post 184.