With a style that has the groove of Dave Holland, the lyrical inventiveness of Palle Danielsson and the big sound of Arild Andersen, Råberg’s playing anchors a quartet that includes Phil Grenadier (brother of bassist Larry Grenadier) on trumpet, Allan Chase on soprano and alto saxophones and Italian drummer Marcello Pellitteri. Grenadier combines the best of Dave Douglas’ midrange with the occasional upper register flights of Kenny Wheeler; Chase has an alto sound that brings to mind Steve Coleman’s on Holland’s Triplicate; and Pellitteri provides everything from feathery brushwork to intense grooves.

"Maya" opens the set, with shifting tempos and structured/free playing. It’s a terrific introduction to the musical bond that exists between the players. While a melodic phrase is used to signal shifts, it is remarkable to hear how in synch the group is.

"Through the Window of Compassion" is a plaintiff ballad which, like much of the album, explores natural sounding irregular meters seamlessly. Råberg delivers a lyrical solo, supported by Pellitteri’s sensitive brushwork.

"Stilts", another irregular-metered tune, still manages to swing effortlessly as Chase solos confidently over a powerful groove from Råberg and Pellitteri that shifts speed throughout.

The title track is a free-time piece that begins with a yearning bass solo, before breaking down into a chaotic free section where Grenadier coaxes almost impossibly low-register notes from his trumpet.

Starting with a gorgeous Arco solo from Råberg, "African Daybreak" moves into a loping 3/4 time soprano solo from Chase before shifting tempos for Grenadier’s ethnically-rooted solo. The time shifts yet again for the final restatement of the theme. As is the case for the whole album, the quartet manages to shift tempos and meters in a natural way that never looses the sense of groove.

Sounding like an outtake from Dave Douglas’ Magic Triangle Quartet, "Estaron" is harmonically open, and both Chase and Granadier deliver fine solos. Råberg and Pellitteri support the soloists with an almost telepathic ease.

"Triptych" is a tender ballad, with Chase’s most poignant solo of the program.

The optimistic "Easter Song again moves effortlessly through a number of feels as players provide solos which are both lyrical and well constructed.

Råberg’s study of South Indian rhythmic Solfege (and a lot of cappuccinos) provided the inspiration for "Caffe’ Nero", where the bass line and melody are seemingly independent. There is exceptional interplay between Chase and Grenadier.

The album concludes with "Angle of Repose", a bit of an anomaly in that it is completely structured. Råberg’s folk-like bass line and Pellitteri’s funky kit work drive a relaxed melody from the alto and trumpet frontline.

The writing is rich and varied, but the emphasis is on improvisation and group interplay. Freed from the restriction of having a chordal instrument in the group, and featuring rhythmic shifts that always feel natural and not forced, Ascensio is a record that will hopefully garner wider recognition for Råberg and the group.