It's so hard to put a unique stamp on the post-rock genre in 2009. Hell, it was hard to do so in 2006.

Constants know this, though. They know that to be unique in a genre as saturated as post-rock isn't necessarily to be good. So all that's left is to create a terrific record and not give a damn what other band it may or may not sound like.

So sure, you could compare The Foundation | The Machine | The Ascension to a host of other shoegaze or post-rock records -- it doesn't matter. What does is that from the first, delicate intonations of "Genetics Like Chess Pieces" to the last overpowering chords of "…Passage," this is a grand and sweeping record that is not to be slept on.

It's all about mood for the Boston trio; the thundering riffs that open "Genetics" quickly segue into a pulsing, melodic rhythm section just laden with distortion. Without being scatterbrained or schizophrenic, Constants keep parts moving at all times. Even just a subtle change in chord progression or drum pattern makes a big difference, and that unwillingness to stay tethered to one sound is what keeps every song interesting.

And it's all a logical progression. The thick, muddy "Genetics..." leads into the airy exposition of "Damien" and the melodic guitar tones keep the mood light. Even towards the end of the song, when the rhythms become awash with distortion and the drawn-out, droning vocals of singer Will Benoit softly resonate throughout, the path of the song and the album is sure. And every song on that path injects a new, interesting wrinkle. "Those Who Came Before Pt. 1" throws in some electronic elements á la Maserati and "Those Who Came Before Pt. 2" relies on minimal instrumentation to gently push the album along.

True to form, just when it sounds like the album is mellowing out, "The Nameless" explodes out of the gate with a veritable wall of distortion and the soft hum of reverb in the background offsets it perfectly. Constants have mastered the art of amalgamating two contrasting sounds into a new and interesting approach, so that each time you listen to any of the songs on the album you're able to hear something new. A new, tiny wrinkle that can either accent a song or change its sound completely. Sometimes the back-and-forth between the two contrasting elements isn't quite so subtle.

"Abraxas Pt. 1" caroms between the powerful riffs and waves of distortion and warm, jazzy chord progressions and before you're able to wonder what path the song is headed down next it veers into wholly unraveled land.

Such is the charm and the strength of Constants.

Power and beauty. Thick bass grooves and razor-sharp riffs. It's not the nouns or adjectives that matter. It's the path and the journey.