BY JENNIFER KELLY

Last December in an interview with BLURT, Laura Veirs said that she had to release the very summery July Flames, her seventh and latest album, in January "for business reasons." Those business reasons became fully apparent at this Valentine's Day concert when a very pregnant Veirs took the stage for what has to be one of the last in a series of concerts before she has her first child. At a stage in pregnancy when many women have trouble standing - and even sitting - for long periods, Veirs had just returned from a string of dates in Europe. Only late in the program did she even acknowledge her condition, announcing, "You know I'm going to have a baby soon," and predicting a little break in the tour schedule - but not a long one. "This baby is going to be a child of the road," she predicted, "So when we tour again, it will be with a baby."

For now, though, Veirs is touring with a three piece band, two of whose members, Alex Guy (as Led to the Sea) and Nelson Kempf (as Old Believers) play opening slots. Alex Guy, sings and accompanies herself on the violin, picking pizzicato patterns during the verse and coaxing long, lush bowed notes in the bridges. Her voice is in the same family as Veirs' - fresh, clear, without much vibrato - and her lyrics, like Veirs' own, littered with evocative natural imagery. Often she sets up a rhythmic loop at the beginning of songs, then adds swoops and throbs of more sustained sounds over it. Her act is a bit like an indie folk version of Anni Rossi, but without the knocking and clicking and bow-banging that Rossi uses for rhythm.

Next, Nelson Kempf plays some acoustic-guitar accompanied songwriter folk, confessing that he's nervous since, after a month in Europe, this is the first time anyone could understand what he's saying. His guitar playing is very subdued, barely audible chords framing songs about childhood homes and familiar territories. His best song comes late in the show and comes from a split with his sometime performing partner Dhani Rosa. It's called "All the Love You Ever Felt Is With You Now," and he brings up Rosa to accompany him on keyboards and the audience in to sing a counterpart of "All the love...All the love...All the love..."

And then with Rosa, there's a welcome burst of absurdity as Old Believers morphs from earnings guitar-slinger folk to a kind of pseudo-electro-soul. This is exuberantly theatrical, acting out a song about waking up and taking a shower with large-scale gestures to Casio beats and Kempf's 1970s wah wah guitar. It's very funny but no one in this very mature audience seems to be laughing. (Kempf is borderline cracking up for the whole set.) "I've got a name for a porn movie," Rosa announces between songs, a propos of nothing. "It's called The Devil Wears Nada." And finally, people seem to get the joke and start to laugh.

Veirs, with her horn rimmed glasses and Hillary headband, fits right in with the Smith College vibe of Northampton. She notes, at one point, that two of her aunts and one grandmother were Smithies and wondered if any of them had ever been at the Iron Horse. She herself could easily be a grad student, even with the bump (grad students have kids, too, after all), and her music, radiantly pretty but with a hard, intelligent spine to it, seems especially appropriate in this town so long dedicated to female empowerment. She starts with "Carol Kaye," the song from July Flame that pays tribute to the 1960s bass player, a feminist icon in her own rite, with Eric Anderson picking out the low-end slides and thumps. Kempf has switched to piano, and Guy plays violin. Everyone sings.

There's no real drum kit on the set, though various players take turns whacking one tom and a kick drum or shaking a tambourine. "Cast a Hook," off the Saltbreakers album, is driven by a thumping bass drum, but many of the songs are more lightly tethered to rhythms set by guitar picking, pizzicato violin or keyboard plunks.

Harmonies are pushed hard, with everyone singing loud and at strident intervals, so that the songs sometimes sound a bit like Sacred Harp gatherings. And Veirs' own voice, which can be soft and reflective, makes sudden leaps and crescendos, chops fluid lines by accenting words unexpectedly and gives the music an unexpected edge.   The tunes, which can seem contained on the record, gain a bit of frenzy live. "July Flame" turns particularly vivid in concert, its slippery guitar slides going vertiginous, its careening violin swooping offkilter. The song is much more intense - and simply better - live than on the record.

The set covers most of July Flame, a couple of songs from Saltbreakers and some older material. Towards the end, Veirs switches to banjo and engages in a speed-dueling hoe-down with Guy. The audience claps along, faster and faster, as the two women accelerate, fingers and bows turning to a blur. Afterwards, Veirs comments, "I know we're getting to about the right speed when we're not smiling anymore. There's nothing left for a smile."

The main set closes with a folky, tightly harmonized cover of Fleetwood Mac's "Never Going Back Again" and the haunting "I Can See Your Tracks." The band returns for an encore of "Sleeper in the Valley" and "Make Something Good," and leaves on a high note. Afterwards Veirs can be found perched on a stool, friendly, conversing, signing CDs for fans, looking not the least bit weighed down or tired by her soon-to-be extra touring partner.