174 Hz, Frequencies
Standing
Concerns Origin of the Name
Currently States The name is taken from solfeggio, the European system of singing syllables, ut, re, mi, fa, sol, la, which Guido of Arezzo drew in the eleventh century from the opening syllables of successive lines of the hymn Ut queant laxis. Guido's syllables name positions within a hexachord. They are relative pitch and carry no frequency.
The New Grove Dictionary of Music and Musicians (Stanley Sadie and John Tyrrell, eds., 2nd edition, Macmillan, 2001) documents Guido of Arezzo's eleventh-century solmisation system, the evidence offered for the claim that the Solfeggio set preserves the tuning of medieval chant. Guido's system assigns a syllable, ut, re, mi and so on, to a position within a hexachord, a relative relationship between notes, not a number of vibrations per second; a singer using it began wherever their voice was comfortable, with no fixed reference pitch at all. Comparing that documented medieval practice against the modern claim, nothing in Guido's system fixes any syllable to any frequency, and the hertz itself is a unit defined in the nineteenth century and named after the physicist Heinrich Hertz, born in 1857, centuries after Guido. The name trades on a real medieval system's prestige without carrying forward anything it actually specified.
Source The New Grove Dictionary of Music and Musicians, 2nd edition, Stanley Sadie and John Tyrrell (eds.)