Nexus comma: Difference between revisions

 

The '''nexuma''', or '''nexus comma''', is an [[11-limit]] [[unnoticeable comma]] with a ratio of '''1771561/1769472''' and a value of approximately 2 cents.  It is the sum of the [[32805/32768|schisma]] and the [[parimo]], the difference between the [[243/242|rastma]] and the [[Alpharabian comma]], and the amount by which a stack of three [[128/121]] Alpharabian diatonic semitones falls short of a [[32/27]] minor third.  Tempering it out leads to the joining of the [[11-limit]] and the [[3-limit]], a fact which, in light of the importance of both p-limits, lends itself to this temperament being dubbed the "'''nexus temperament'''"- the source of this comma's names. While the importance of the 3-limit is generally accepted (see [[Pythagorean tuning]], [[circle of fifths]], [[FJS]], [[Helmholtz-Ellis notation]]), it can be derived mathematically that the 11-limit is an excellent basis for quartertones in terms of ratio simplicity, and the 11-limit can be shown to host a clear sequence of intervals in which every other member is the octave complement of what is effectively a stack of [[128/121|diatonic semitones]] (see [[Alpharabian tuning]]).  For a list of temperaments that temper out the Nexuma, see [[Nexus family]].