My understanding of progressive rock was largely informed by my dad, and the incessant noodling he exposed me to from an early age. It was obnoxious and fascinating, this gauntlet of bands that stubbornly refused to compose music that was immediately pleasant to the ears. After years of growing up on doo-wop and classic rock, it was a shock to have Gentle Giant and King Crimson come around to confront me with their unapologetically abstruse sounds.

Even still, my dad failed to show me the breadth of prog-rock, as evidenced in his lack of exposing me to Captain Beefheart. There was a whole world of complex, idiosyncratic sounds to mined, and I had only heard the tip of the iceberg. Later, when I would discover bands of my own volition, I would show them to my dad, and he would frequently have the same response. The Decemberists? They're prog-rock. The Flaming Lips? Definitely prog-rock. Pixies? Just because they're sweaty and wearing T-shirts, it doesn't mean they're not prog-rock.

To my dad, progressive music is the most fundamentally undefinable genre in rock. It's like pornography: he knows it when he sees it. So, the question then arises about what it means to make "good" prog-rock. Initially, the question may seem absurd, but it gets complicated in the unraveling. When an entire genre of music is devoted to the idea of tearing down the structures of popular music and creating something ahead of its time, how can you truly judge the merits of one band versus another? Of course, the test always remains that whatever hits your ears right is good, but taken from an anthropological stance, the merits of a progressive band become less clear.

Take Tacoma band Bes, for instance. On their Facebook page, they define themselves by playfully vague terms like "speed-folk," in addition to the nebulous label of prog-rock. Still, what they bring to the table is a far cry from the Genesis and Jethro Tull albums that my dad was weened on. Combining elements of feverish folk, blues-rock, impeccable harmonies, breakneck time signature changes, nü metal, herky-jerky electronica, noise-rock, dance-punk and Afro-pop inflections.

It's been established (by me and others) that music critics tend to find themselves drawn to difficult music after years of writing about stuff that just sounds "good," whatever that means. There are only so many ways of saying that something sounds "dance-y" or "folky" or that something totally melts your face. Finding a band like Bes is an opportunity to write about something outside of your immediate experience. It's a way of bringing you out of yourself in a manner that exposes you to stimuli that would not otherwise have penetrated your surface. In a similar way, I think part of the joy of listening to a prog-rock band is a way to escape from the lands of expectations. The only expectation you have when listening to a prog-rock band is one of wanting to hear something novel.

So, do Bes accomplish the goals as set out by me on what makes a prog-rock compelling? Well, let's take a look at their song, "Nugget," which sounds like music that would accompany an assembly line montage in the dreams of Kraftwerk. It's a lovingly rendered synth-rock instrumental that would make Taco happy. Elsewhere, we find a furiously strummed epic in the form of "Sugar," adorned with horns. "The Tribe" is Bes at their most dedicated to the idea of changing sounds and challenging preconceptions.

Do they surprise? Not always. But, then, a surprise wouldn't be a surprise if it happened all the time. But, if there are a million bands taking stabs at progression, Bes gets points for taking a horizontal slide.

BES, w/ guests, 9 p.m., Saturday, May 2, Half Pint Pizza Pub, 2710 Sixth Ave., Tacoma, cover tba, 253.272.2531