The Brentano Quartet, now in its third decade, has forged a clean, light-textured style and offers sometimes bracing ideas about familiar literature. In two large Beethoven quartets at the Wolf Trap Barns on Friday, the Brentano seemed almost like two different groups; the one playing Op. 59, No. 2 was rushed sometimes to the point of triviality, and the one playing Op. 131 weighed everything down with profundity. I would never presume to ascribe motives for anyone’s interpretations, but the Op. 131 quartet was the subject (and soundtrack) of the recent feature film “A Late Quartet,” full of angst and psychodrama, to which the Brentano contributed the soundtrack.

Here, their performance of the earlier work was thought- provoking­ and propulsive. In the first movement, tempo fluctuations were excessive (to these ears) but done with great conviction and logic. They introduced an idea of articulating Beethoven’s obsessive syncopated rhythms as two notes instead of one, but they did it inconsistently. The molto adagio also had a new take on the opening violin theme, articulating three notes (as no­tated)­ rather than two (as everyone else plays). These details and many others showed impressive depth of thought. The Brentano’s tempos in the scherzo and finale, though, were breathless, devoid of any grandeur and, in the final coda, almost cartoonish.

The room seemed darker for Op. 131; the opening fugue was pregnant and deeply melancholy. The complex dynamics of the allegro were only approximated, but at least the Brentano tried. The huge central variation movement was full of fantasy and emotion, each section strongly characterized. The extended 9/4 variation seemed to come from another solar system, wispy and eternally distant. But then, those of us waiting for a darting scherzo like the one from the earlier quartet were nonplussed at the Brentano’s staid, heavy in-the-string playing here. And in the finale, they slammed on the brakes for the lyrical second theme to the point of disjunction; it was like two different pieces, the gear shifts never really working.

The Brentano is, overall, quite a good group. They are more successful at softer dynamic levels than stronger ones, their leader appears to arrange his bowings to avoid doing a spiccato, their intonation is not always faultless and their cellist’s facial affect is that of someone doing battle with a cruel adversary. But they make a lovely corporate sound and, agree or not, their interpretations carry gravitas and, often, expressive force.

Battey is a freelance writer.