Editing Tritone substitution (section)

==In other tuning systems==

The fact that a chord and its tritone substitution have the third and seventh in common is related to the fact that in [[12 equal temperament]], the [[Lesser septimal tritone|7:5]] and [[Greater septimal tritone|10:7]] ratios are represented by the same interval, which is exactly half of an octave (600 [[Cent (music)|cents]]) and is its own inversion. This is also the case in [[22 equal temperament]] and tritone substitution works similarly there. However, in [[31 equal temperament]] and other systems that distinguish between 7:5 and 10:7, tritone substitution becomes more complex. The [[harmonic seventh chord]] (approximating 4:5:6:7) contains a small tritone, so its substitution must contain a ''large'' tritone and therefore will be a different (and more dissonant) chord type.<ref name="31et">{{cite web|url=http://31et.com/interval/15/|title=Lesser Septimal Tritone}}</ref>