falsetto vs high-pitched

falsetto is a noun but high-pitched is not a noun.

Word	Noun	Adjective	Verb	Adverb
falsetto	Yes	Yes	No	No
high-pitched	No	Yes	No	No

falsetto (noun)	high-pitched (noun)
a male singing voice with artificially high tones in an upper register

falsetto (adjective)	high-pitched (adjective)
artificially high; above the normal voice range	used of sounds and voices; high in pitch or frequency
	set at a sharp or high angle or slant