Liturgy plays Kings and White Ring play Five Star on Friday. Dreamers of the Ghetto play City Plaza, Dawn Golden and Rosy Cross play Five Star and Toro y Moi play Lincoln Theatre on Saturday.

I don’t know if it’s the program’s default setting, but in my iteration of iTunes, the genre of a particular recording is something I almost never see. With the window fully expanded across the screen, the name of the song takes the left-most and widest column, trailed to the right by track length, band name and album title. Genre is beyond the fold and to the right, quarantined beside the column for rating stars (which I never use) and my play count (which only reminds me that I often get obsessive).

And now, glancing at my genre column, I realize that it’s not even very useful or accurate: Instead of actual musical genres, a few albums are simply tagged with the name of whatever illegal MP3 blog from which I “sampled” them, while that great Cosmonauts album is tagged “Permanent,” which is less of a comment on its quality and more of a reminder of the Chicago label that released it. The bulk of the genre entries are actually entirely blank. Bon Iver, at least, is labeled “Hornsby.”

Still, every few weeks, someone will send a familiar question to the Hopscotch catch-all email address: “Do you have a list of all the bands playing, sorted by genre?” We don’t, actually, and I don’t know that we could: Dreamers of the Ghetto sound like a mix of Genesis and The Replacements, which I suppose makes them “alternative rock,” but is that still a genre, even? Dawn Golden and Rosy Cross makes pop songs broken by static and toy samples and hip-hop bass; is that shoegaze? Not even two years ago, Toro y Moi unwillingly served as the key in a niche called “chillwave,” but his new LP, Underneath the Pine, is far too sophisticated for the day-at-the-beach vibe that term implies. If my parents ask me what kind of music White Ring makes, I’m not going to say “witch house.”

I suppose both as a music critic and, these days, a festival organizer, some sufficiency with musical speciationwhat makes a blackened doom band different from a blackened death act, and at what point does or did James Blake cross beyond being only dubstepwould be nice. But it seems that listening culture is shifting thankfully away from such artificial and arbitrary divisions, in no small part because of the ways in which the Internet gives us open access to everything. These days, you no longer have to figure out which section of a record store fits your tastes; these days, you can simply browse your tastes with push-button ease. This system of exploring and listening seems much more in line with the way the best music is made, as the product of some internal and personal impulse rather than the forced contrivance of a system of artistic assets and qualities.

There are, of course, those that care deeply about genre, either on a scholarly level (the evolution of any popular genre, after all, remains always a potential crossover smash for an academic press) or on a provincial, proprietary, personal level. Those sort of encampments and encroachments are rarely more evident than they are in heavy metal, a genre of microgenres and myriad stylistic delineations, a form with allegiant websites whose sole purpose seems to be debating and deciding what is metaland then detailing it, exhaustively.

In the past few years, no metal interloper has been scorned with the faithful’s fury quite like Hunter Hunt-Hendrix, the founder, frontman and sole songwriter in the Brooklyn band Liturgy. Their 2009 debut, Renihilation, was certainly good, with Hunt-Hendrix’s serrated caterwaul pushing over guitars that inhaled and exhaled and drums that tweaked the traditional black metal patterns. Renihilation evoked some scorn, earning Liturgy the epithet of “Brooklyn hipster scum” and Hunt-Hendrix the tag of pretentiousness for his consistent mention of composers like Glenn Branca, Rhys Chatham and La Monte Young. (It should be mentioned here that Liturgy guitarist Bernard Gann is the son of essential classical composer and critic Kyle Gann; that Hunt-Hendrix once told an MTV reporter “The inventor of spectralism taught at my college [Columbia University]”; and that, in 2009, Liturgy played the New Yorker Festival.)

But Liturgy persisted, signing to the indie rock label Thrill Jockey for their second LP, a mostly perfect, hourlong epic of starts, stops, fits and fists called Aesthethica. Liturgy not only pushed the black metal form to more extremes, they also explored those other impulses more directly, particularly on the exhilarating, more math rock-than-metal instrumental “Returner.” What’s more, in the interim, Hunt-Hendrix delivered a talk at a Brooklyn black metal symposium that was soon reprinted as a small bookreally, more of a handsomely designed religious tract than a textbook. He wrote of a “Haptic Void” and differentiated between the Hyperborean Black Metal of the past and his own Transcendental Black Metal. “The act of renihilation is the betrayal of Hyperborean Black Metal and the affirmation of Transcendental Black Metal,” he wrote. In summary, he sort of told everyone else to fuck off.

The hate was intense, immediate and pretty disheartening. For Renihilation, people had ribbed Liturgy for their education, geography and choice to wear street clothes in a genre where a fashion of corpsepaint, leather and elaborate jewelry is the norm. As Hunt-Hendrix told me in May, though, Aesthethica wrought a whole new form of vitriol: “Now, it’s like, ‘These guys are fags. These guys deserved to get fucked in the assto death.’ It’s this violent, gay, rape stuff. It’s all over the place, and it freaks me out a little bit.”

Those vile reactions, however, mean that Liturgy is onto something, that they’ve crossed some sacred artistic boundary, that someone feels threatened enough to resort to base-level insults disconnected from reality. It’s probably more than a little bothersome for Hunt-Hendrix; for the rest of us, though, it means someone’s pushing into fresh, fertile ground.