In "Art and Cognition", from The Romantic Manifesto, Rand pretty much "bashes" folk music, sometimes explicitly, as in the quote Thoyd Loki provided, and here:
"The products of anti-rational, anti-cognitive "Progressive" education, the hippies, are reverting to the music and the drumbeat of the jungle.",
but she also does it implicitly, throughout that chapter; but let's not forget that in the very same essay she says: "Until a conceptual vocabulary is discovered and defined, no objectively valid criterion of esthetic judgement is possible in the field of music."
Though I admire Ayn Rand intensely, I don't agree with some of her ideas about music. I know for a fact, for instance, (and to go in the opposite direction from folk music, for a moment) that some of the most complex music ever recorded sounds like random noise to the untrained ear, in the very same manner that a complex mathematical equation will look like gibberish to someone who doesn't know what it means, and in the very same manner that a foreign language will sound like gibberish to someone who doesn't understand it.
I am fairly certain that Ayn Rand wasn't an expert on musical theory, and I'd say that there are excellent odds that certain types of experimental or avant garde music probably sounded like incoherent noise to her. On the one hand, she could denounce folk music because of its redundant, repetitive simplicity, and feel, perhaps justifiably, that such music was beneath her since it offered no challenge to her intellectually, and caused in her a purely negative emotional response; but on the other hand, due to the fact that she was not an expert in musical theory, she ought to have (and very well may have) recognized the possibility that certain types of music might actually be beyond her in the same sense that certain types of music were beneath her. At one point she seems to concede this, during a discussion of the similarities and differences between language and music:
"Western man can understand and enjoy Oriental painting; but Oriental music is unintelligible to him, it evokes nothing, it sounds like noise." (Art and Cognition, Romantic Manifesto.)
I would suggest that it sounds like noise to him because of his ignorance primarily, and only secondarily because of the difference in culture and environment; and Rand's statement is only very generally true, as I'm sure many Western people can and do enjoy Oriental music. (I might not be able to appreciate Oriental music until I had some sense of their musical philosophy and, more importantly, their formal and technical approach to musical theory and composition. Once I learn something about that, I am in a much greater position to appreciate and enjoy the music. Of course, I can still dislike it. How we respond to music emotionally is still in the realms of the subjective. I'm entitled to my opinion, but I'd rather have an educated opinion than one which is arrived at by way of ignorance.)
But later on, Ayn emphatically denounces what she calls "modern music", and says that she is objectively certain that such music is NOT music. There is a reference to "non-periodic vibrations", and as examples of these she cites sounds like traffic, coughs, sneezes. There are no other examples, so what she seems to be denouncing under the umbrella of "modern music" are compositions which include these non-musical sounds, or noises. I agree, noises, in themselves, do not constitute music; but non-musical sounds can often be incorporated into musical compositions with great effect. Tchaikovsky's 1812 Overture is a prime example, which uses cannon-fire to augment the power of the music; Mahler's Sixth Symphony has the famous (or infamous) "hammer-blows". I wish she had gone into greater detail about what she labels "modern music". As it stands, the term as she used it is lamentably vague, and one can only speculate as to what she might have thought of the various different kinds of experimental music, whether it be orchestral, electronic, or what.
Ayn says (and I'm paraphrasing because it's difficult to hold a paperback open in your lap and type at the same time) that if any sort of noise is introduced into what is supposed to be a musical composition, that removes said composition from any consideration as a work of art. I have to respectfully disagree. I know of one chuckle, for instance, that I would absolutely hate to see removed from the piece it is included in. I'm refering to Robert Plant's giggle, chuckle, or guffaw, which opens up "Whole Lotta Love", on Led Zeppelin's second album. I suppose the sound itself doesn't constitute a musical sound, but it's incorporation into the song is priceless. Just my opinion, of course, but I think it would be daft to suggest that we should be such purists as to disallow the creative use of non-musical sounds in otherwise musical compositions.
Back to folk music. Folk music can often be life-affirming, joyful, and a sheer pleasure to listen to. I was raised listening to Simon & Garfunkel, Peter Paul & Mary, John Denver, and the like. It was my father who played this music in the house, and it was my father who first introduced me to the philosophy of Ayn Rand. My father played us a lot of folk music, but he was nothing like a hippie himself. In fact, he couldn't stand the whole hippie movement, even though he was a member of their generation. He was in the Air Force, was patriotic, was an advocate of capitalism, was an atheist to the marrow of his bones, never used drugs except for the occasional beer, and was interested in philosophy. He's changed a bit since those days, but he's still nothing like a hippie. I'm nothing like a hippie either. Folk music, in a variety of forms, has existed since ancient times, and folk artists should be judged as individuals, one artist at a time, not just lumped into a single category and dismissed out of hand. To do that is to make an error of prejudice, plain and simple.
I don't think that any real connection can be made between people who enjoy folk music and a lack of intellectual caliber. It may be true that in general, the common herd has responded more readily to more accessible types of music, but of these types we can include certain kinds of chamber music, dance music (including symphonic dances and waltzes), operetta, show-tunes, gospel, hymns and masses, dixieland jazz, blues, rock, rap, what have you, as well as folk, which includes country and western music, whose fans are often the polar opposites of hippes insofar as their sense of life, their philosophy, their moral and political beliefs; but at the same time, it's a plain fact that some of the best and brightest people in the world have enjoyed these accessible forms of music as well. I'd even go so far as to say that there might not be any definite correlation between musical preferences and levels of intelligence. Musical tastes seem to be more dependent on cultural and ethnic backgrounds (as well as the respective knowledge or lack of knowledge in regard to musical theory) than on intelligence, sense-of-life, or worldview. Of course, I could be wrong, and I would happily be corrected.
The idea that certain types of music can be psychologically damaging (an idea which Rand seems to espouse), is interesting, and might warrant some investigation, but in just looking over a few threads here at this forum we can see that rational people can and do enjoy all different kinds of music, from rock and heavy metal to alternative, to classical.
I remember reading somewhere that Ayn Rand disliked Beethoven's music, calling it "malevolent", or something; this has always bothered me. It bothers me because it's weirdly evocative of a popular extreme-feminist belief that Beethoven's Ninth Symphony is a depiction of the mindset of a male in the act of rape. Not only is this a belief, but there are people teaching this very idea in certain universities. This kind of nonsense is frightening, folks. For myself, I find nothing but great beauty and benevolent power in the symphony mentioned: joy, and hope, and exquisite, life-affirming passion. I have nothing against a person taking something wholly different than I do away from music, any music. It's natural and normal; but I suggest that it's unwise and even dangerous to foist one's own subjective response to music on others by way of some sort of presumed intellectual authority. Not that Rand did that, necessarily, but I'd be dishonest to say I didn't think she came somewhat close.