At its essence, post-rock can be defined by four universal rules. First, long and cumbersome titles are king. Second, the songs themselves are usually equally as long (15 minutes is generally considered acceptable). Third, it's best if at least some of the tracks end with the noise of long-suffering instruments in tangible torment (see: Mono's "Com(?)"). Finally, a general thematic feel of impending doom is welcomed. If all this sounds a little flippant or disrespectful, it isn't: these factors are what make post-rock so repeatedly listenable.
Crescendo-core represents the LOUDER end of the spectrum. If you want a spiritual forefather, Scotland's Mogwai are undoubtedly the ferrymen to the island of all things long and loud. What makes this music so great, though? Its 'epic 'quality: crescendo-core is always cinematic and huge in scope. One of the best known collisions of post-rock and popular culture epitomises this: when Godspeed You! Black Emperor's "East Hastings" rears its unsettling head during Danny Boyle's 28 Days Later it makes the scenes of zombie destruction and a desolate UK infinitely more poignant.
Crescendo-core is a pretty universal concept; how many bands do you know, or have you been a member of, that end their rehearsals with an epic extended jam? The desire to build guitar patterns, to reach some massive instrument-bashing climax — and basically to make a whole lot of noise — infects us all, although some take this inclination and craft something sublime.