CMi6/Ami7-5-F9 4 STRING GROUPS E-D-G-B [E] [A] [D] [G] [B] [E] * * Eb * C * * * * A * * G * * * * * * * * * Eb * A * G C * * * * * * * * * * A * * * C * * Eb G * * * * * * * * * C * A * Eb * * * * * * * * G * * D-G-B-E [E] [A] [D] [G] [B] [E] * * Eb * C * * * * A * * * * * * * G * * * * Eb * * * G C * A * * * * * * * * A * * * * * * Eb G C * * * * * * * * C * A * * * * * * Eb * * * G * * A-D-G-B [E] [A] [D] [G] [B] [E] * * * * * * * * * A * * * C * * * * * * * * Eb * * * G C * * * Eb * * * * * * A * * * * * * Eb G * * * * * * * * G C * A * * * * * * * * * * * * * E-A-D-G [E] [A] [D] [G] [B] [E] * * Eb * * * * * * A * * G C * * * * * * * * * * A * G C * * * Eb * * * * * * A * * * C * * Eb * * * * * * * * * G * * * * * * * * * * * * * * * * A-G-B-E [E] [A] [D] [G] [B] [E] * * * * * * * * * A * * * C * * * G * * * * Eb * * * * C * A * Eb * * * * * * * * * * * * * Eb G C * * * * * * * G * * A * * * * * * * * * * * * * It's worth noticing that all that has happened is we have taken the E natural, which is the major third interval, and lowered it one fret to Eb, which is the minor third interval of the C Maj 6. However, there are four implicit synonyms! Much more important is to notice that this also spells an Ami7-5 Chord: A-C-Eb-G. In fact it is more useful to see this voicing that way. It is also an F9 without a root. (F)-A-C-Eb-G. Which is also very important for practical chart reading. Somewhat obscurely, it can even function as an Eb13-5, but you may find that is a bit of a stretch. However, for voce leading in specific contexts, it may serve. Again, your taste will dictate their applications in context. Some things will simply sound better than others in the course of applying these voicings to specific progressions and larger arranging contexts.