I understand that shok is ervah as that is explicit -but that the kol is naveh and hair attractive does not seem to be a 'proof' that it is a definite ervah -but just seems to mean that it is some attractive item! it seems subjective in a sense, since for any man, different things might be attractive! if so, why didnt the gemara just make a blanket statement that anything to which a man has a yetzer for - that is assur for shma - and yet we said above that less than a tefach, i.e a little toe is not a problem? isnt this a stira?
mendy, ny,usa
The verse would not praise a woman in Shir ha'Shirim except for elements that would arouse the love of a normal, ordinary man for a woman. Therefore, the fact that the verse praises her for her hair and voice implies that these parts are, for an ordinary person, parts that distract him from Kavanas ha'Tefilah, and they are considered Ervah.
(Even though there are women whose hair and voices are not at all attractive and are rather quite ugly, nevertheless since it depends on the eyes of the beholder, as you wrote, the Torah prohibits Se'ar and Kol of every woman to every man, since these parts are prone to arouse the love of a man for a woman who anyway is attractive to the man. There is no concern for this with other parts, though, for normal, ordinary people.)
M. Kornfeld