An entertainment tetrachord...

Edited: this one is number 497 in Divisions of the Tetrachord

On page 193 there are even more sci-fi tetrachords, and others that correpond to phi intervals as well.

This one is for entertainment purposes only (probably).

Anyone who has been working with phi in tuning, or following the recent threads,
is going to be familiar with the interval of approx. 466 cents, which appears
many time in different phi tunings: phi mod2, golden sections of golden
sections, and so on.

It is maybe surprisingly close to, and in most situations indistinguishable
from, a Just interval relatively low in the harmonic series, 17/13.

Now if we make a tetrachord in the most vigorous and traditional way we can with
this interval, we get something beyond the "hyperenharmonic", more like
the "hysteroenharmonic". :-)

104/103, 103/102, 17/13.

The pyknon is 52/51, the CI is 17/13, and it's really quite ideal... on paper.
Of course in real life the microtones are about 16 cents, not something we'd
usually consider a scale step. With an undivided pyknon, though, it's very good
to my ears as an ultra-austere enharmonic, and anyway I'm a big fan of the
interval range that can't really be called a "third" or a "fourth", as are a
couple of others on the lists if I recall correctly.

-Cameron Bobro