Who would have imagined that one of the most convincing inside/outside sessions of the year would come from an unheralded — at least in North America — Portuguese combo with a French baritone saxophonist guesting? But it’s true.

Estoril-born bassist Carlos Barretto’s Lokomotiv could be an object lesson in how to produce a CD that swings from the get-go. Yet it also never gives the impression that any of the musicians are holding back their freeform tendencies to fit anyone’s idea of what the proper idea of jazz is.

You can hear this as early as the title tune where the bassist’s intro delivered with a weightlifter’s power locates itself firmly in the tradition of Charles Mingus’ “Haitian Fight Song”. It’s followed by basement snorts from French baritone saxist François Corneloup. Although his sonorous output here makes many low sax types sound as if they play sopranino, Corneloup also has enough control to showcase R&B-style honks and siren-like miultiphonics that almost sound like trumpet lines. His exercise in low pitches is accompanied by a work out on the trap set and bell tree by drummer José Salgueiro, that is subsequently subverted by horse whinnies from Corneloup. Finally the saxman uses his bone-shaking timbres to reach a climax.

A flourishing presence on the Continental scene, Barretto has taken sideman gigs with musicians ranging from mainstream modern pianists George Cables and Kirk Lightsey to more outside folk like soprano saxist Steve Lacy. His own trio has been around since 1997, always featuring guitarist Mário Delgado, a hard-hitting stylist who also works accompanying Portuguese pop singers. Barretto recently returned the favor, playing on Filactera, last years’ well-received solo CD by the guitarist, also on Clean Feed.

Percussionist Salgueiro also moves back-and-forth between popular and improvised music in Portugal, while the self-taught Gallic saxist Corneloup has worked with trombonist Yves Robert, guitarist Marc Ducret and others, in bands which skirt the mainstream.

Perhaps it’s the brotherhood of the reverberant, but the bassist and sax man offer fine work in tandem here. Moving between a more mellow Gerry Mulligan-like style and some freak, flutter-tongued high pitches, Corneloup’s more abstract overblowing encourages lumberjack-powered strokes from Barretto, plus some Amerindian tom tom color from Salgueiro. Ballads are no problem either, as on “Klinfrik”, where the baritone man trills out tones that move from tenor emulation to full sonorous sounds. Meanwhile the bassist’s lines encompass 12-string guitar strumming emulation as well as Classic Jazz slap bass.

Seemingly too polite to interrupt — or often solo — when the guest is featured on certain tunes, Delgado reserves his best work for his own features. “Casa Branca” has a vibrating groove that seems to come from rock music. On it, his razor-sharp note patterns resemble those of a more modern Grant Green, although his double-timed, lead guitar licks are more contemporary and he lacks the blues-gospel base.

Meanwhile, on his own “O Balão na Cama do Faquir”, Delgado sounds as if he’s flat picking the tune backwards, and is then met with enough emphasized, unison textures from arco bass and airy baritone that it almost appears as if he’s working with string and reed sections. As Corneloup blares away, Barretto speedily double stops and Salgueiro contributes fast conga-style drumming. A tempo change introduced by fuzz tone effects from Delgado puts the piece in the pocket, with funk-based asides from the bassist and baritonist and the guitarist finger wiggling for greater effects.

Whether you’re a dyed-in-the-wool mainstreamer or thrill-seeking experimentalist, there will likely be something on Lokomotiv for you.