Of course, with all these extensions comes a problem, which is the fact that you can only play six different notes simultaneously on a guitar. Consequently, some notes may have to be omitted from the chord to accommodate some instruments, like the guitar.
The guidelines for omitting notes in chord extensions are fairly simple:
- The first rule is never remove the root. If you remove the root, the chord’s tonality changes, and it becomes substantively different.
- Never remove the third or the seventh, because these intervals designate whether the chord is major, minor, or dominant.
- Never remove any of the intervals that are altered, if you do, the chord can no longer be classified for its namesake. (If you were to remove the flat third from a minor chord, you are left with the root and the fifth, which is considered to be a fifth chord dyad.)
Of course, some of these rules will be broken, such as never removing the third and omitting the root (some musicians de-emphasize the root so it appears to be omitted, meaning they play the root in a staccato fashion, under-emphasis it, or notate in the transcription as optional).
Examples of the intervals most commonly removed from chords are as follows: the ninth from a minor eleventh or major thirteenth; and in minor thirteenth chords, the ninth, and eleventh can be omitted; furthermore, the third may be removed from a dominant eleventh (as previously outlined). And often, musicians drop perfect fifth in lieu of a more essential extension or interval, but one should note that in removing intervals from a chord, one alters its sound from the original tonal quality.