Originally Posted by 3daveyO3
...in some situations like the chord that Truman used as an example, having a G next to an F##(G#) is a tight and very dissonant interval of a minor 2nd. So by playing one of them an octave higher, it gives the interval a bit of breathing room so to speak...

Davey, I understand what you were saying, but just to clarify an "F double-sharp" or "F##" is a "G" not "G#". As Dunbar eluded too early-on, the sign for "double-sharp" is a slightly modified "x" so "Fx" = "G" (also, as you and Dunbar wrote, this is "enharmonic").

Now that we're clear, I agree 100% that spacing is the key (no pun intended crazy) If you want to have complex colours in your chords, but are not a fan of dissonance, then you need to space them out (i.e., utilize the concept of the "octave"). HOWEVER this will change with the Range of your instrument. Low tones, like Bass and Tenor ranges, need much more spacing because they get muddy very quickly. A Major 3rd (consonant interval) on the low end of the piano is pure mud when compared to a Major 10th (same notes, just farther apart). Conversely, if you are in a high range, you can cram a lot of notes very close together and still get away with it. On piano, generally speaking, anything above "middle C" is high enough for intervals like Major 2, or "suspended 2nds." Below "middle C" you start to see much larger spacing. BTW I think this falls under the category "Voicing" or "Chord Voicing" if you want to research.