5,5,7,7 addenda

Hello. Regarding the chord 3-8-10-15 just mentioned, where you have
two pairs of equivalent difference tones (10-3, 15-8 =7; 8-3, 15-10
= 5), which I guess could also be seen as an overlay of two chords
(3-10-15, and 3-8-15) having the same set of simple difference
tones -- I found other chords with the same property (eg, 6-9-10-13,
3-5-7-9, 5-6-8-9, etc).

Hopefully it's not just my bias for major seventh chords, but
comparing 3-8-10-15 to the other chord examples, it has a perhaps
unique feature. The number of diatonic scale steps between harmonic
numbers 3 and 10, and 8 and 15, are in a 2:1 ratio (12 and 6,
respectively; measured in semitones, it's 21 and 11 -- almost 2/1).

Perhaps there's a balance in this chord between the arithmatical
measure of it's intervals (the difference tone value) and the
logarythmic value of the interval (the step length). What do you
think?

thanks, Kelly