BY JENNIFER KELLY

Remember that Mike Meyers skit on Saturday Night Live?  The one where he wears a kilt and a tam and tends a shop called "If It's Not Scottish, It's Crap"?  Well, tonight's show is 100% Scottish, 100% loud and 0% crap.  How do you like that, lassie? 

Mogwai, Glaswegian progenitors of ear-blasting post-rock, have taken the equally loud, equally Celtic Twilight Sad on this year's North American tour, and James Graham, the emotive heart of the younger band is trying hard to fit in.  "They said backstage that you'd like us if we said this," he ventures at one point, haltingly, as if speaking from a Berlitz phrase book.  "Go Celtics?  Rangers suck?" 

With a new record in the can - and set for a later 2009 release on FatCat - the Twilight Sad have come armed with a lot of new material.  The first song, now tentatively titled "Downstairs", starts, characteristically, in a barrage of drums, drummer Mark Levine sweaty and red-faced almost from the show's first minute.  The plaid sweatered Graham sways side to side with the beat, mic in a two-handed clutch, howling and crooning lyrics about ominous "People downstairs..." presumably parents, presumably up to no good.  Besides Devine and Graham, the rest of the band, Andy MacFarlane on guitar and other instruments, Craig Orzel on bass - are rather stolid, cranking unholy levels of noise without even a twitch of the eyebrow.  But this is fine, because there's already an ocean of drama in songs like "That Summer, At Home, I Had Become the Invisible Boy", with its giant pulverizer of a beat, its tremulous volumes of guitar feedback and its anguished cries about how the "kids are on fire in the bedroom."  Then it's the clickety clack of double sticks on rims, as Graham turns to whack away at Devine's drum set and the guitars build into "Talking with Fireworks." 

The Twilight Sad's songs nearly all start in a deafening pound of toms, nearly all end in a dissolving wash of feedback, but in between, there's a delicate balance of rage and uncertainty, vulnerability and angst.  The songs are very much like being 15, defiant and isolated, but not quite ready to go it alone yet, with shadowy adult figures a source of both irritation and vague comfort.    Graham is, obviously, a few years older now than when he wrote Fourteen Autumns and Fifteen Winters, and the new songs seem slightly more polished, slightly less impassioned, more of a show than piece of his heart.  They also seem to be more outwardly focused than the earliest materials, the dialogue occurring not within a frustrated boy's head, but rather with living, breathing people...and often girls.  One recent addition, glistening with long strands of guitar feedback, seems to address a lover, rather than an unfair world, slipping in the lyric "If you say go, there's a chance that we're running scared."  Another, "Untitled #28", admonishes, "Don't frown" over and over again. 

By contrast, the older songs, "Cold Days from the Birdhouse" with its long a capella opening and closer "I Am Taking the Train," seem more feverish, surreal and unplanned...and a good bit more affecting.  Graham is riveting in "Cold Days", spitting out the repeated "Romantic gestures" line in a wild-eyed rage of sarcasm, so that it means nearly the opposite.  And the hard rocking, guitar bending, cymbal-slashing finale of "Taking the Train" builds into a sublime frenzy, as loud and aggressive as a teenager rampaging through his room in a rage.  Twilight Sad may be growing up - it happens to everyone - but they've got a bit of the old frustration left. 

I've been hearing stories all week about how freaking loud Mogwai is, stories about whole sections of the crowd bent over holding their ears, about ringing that doesn't go away for days.   And yes, they are loud and you should wear earplugs, but it wasn't painful, not much louder than Sonic Youth or Kinski really, and then only at the big surges.  Mostly the Mogwai set was just beautiful, tranquil, mesmerizing...only occasionally did you notice the buzz of the bass was rattling your shirt. 

Mogwai played songs from four of its six studio albums, plus one ("Summer") from the Ten Rapid compilation.  The first two songs spanned 11 of their 15-plus year career, the opener  "I Am a Long Way from Home" from 1997's Young Team, the second "I'm Jim Morrison, I'm Dead" from last year's The Hawk Is Howling.  Yet though there has been some development since the beginning - the addition of Barry Burns on piano, for one thing - Mogwai's body of work hangs together in a remarkably cohesive way.  "Jim Morrison"'s three piano chords hang suspended in the air, lingering with the same melancholy meditativeness as cuts as cuts like "Punk Rock" from Come On Die Young did a decade ago.  The church-like organ drone, the wavery washes of altered guitar in "Scotland's Shame", another Hawk song are just as luminous, just as glacially-paced grand as "Hunted by a Freak" from Happy Songs for Happy People, five years before.  Ponderous beats, bell-clear melodies, blistering surges and delicate piano flourishes...everything melts into a continuous sort of bliss.  The band, too, seems to be caught wholly in the groove.  Bassist Dominic Aitcheson nods slowly in time with the beat, as colored stage lights flicker.  Guitarist Stuart Braithwaite rocks side to side, shoulders writhing as the music pour over him.   

Not that Mogwai isn't capable of real, ear-shattering climaxes.  A late set venture into this year's "BatCat," an encore performance of "Fear Satan" make volume an almost tangible presence, as shattering waves of guitar sound cascade off the stage.   It is not really painful, not as extreme as you might expect, but still impressive, especially since, even at its loudest, Mogwai manages to be profoundly beautiful.