Jupiter String Quartet at home in Rockport’s new music hall

The Jupiter — violinists Nelson Lee and Megan Freivogel, violist Liz Freivogel, and cellist Daniel McDonough — has become a mature, fully developed ensemble in the four years since its members left the quartet training program at New England Conservatory. It has a warm, refined sound and a tensile interpretive style. Both sides were on display in Haydn’s Quartet Op.76 no. 2, (“Fifths’’), whose first movement was played with an almost Beethovenian weight and intensity. Yet even in its most fervent moments one could hear every detail of the music’s internal dialogue, thanks not only to the Jupiter’s sensitive phrasing but the warmth and presence of the acoustic. They gauged the finale’s energetic and unexpected turns with aplomb.

Dvorak’s “American’’ Quartet is the kind of repertory staple whose ubiquity prompts disdain among some chamber music devotees. But the Jupiter’s reading — lyrical and involving yet devoid of schmaltz — reminded you why the piece became so popular in the first place. The slow movement was mesmerizing: Its languorous melodies seemed to spin out into infinity, yet always with a sense of direction that was aided by the quartet’s scrupulously graded dynamics. McDonough’s cello pizzicatos told a whole story in themselves.

After intermission three fourths of the Jupiter — minus Liz Freivogel — were joined by five colleagues for a rarity: the Octet for Strings, Op. 7, by Romanian composer Georges Enescu. Written in 1900 in an ardent, late-Romantic idiom, it’s gripping in parts but drags over the long run. The octet lasts about 40 minutes; somewhere in its ceaseless counterpoint, passionate declamations, and oddly static harmony, a great 20-minute piece is hiding.

It is, nevertheless, a major undertaking, and aside from a few early tuning problems, the performance was all one would wish for. One of the chief delights was hearing the interweaving solos of violinist Andrés Cárdenes and violist Marcus Thompson. And the hall showed how well it could handle what was at times almost an overabundance of sound.

David Weininger can be reached at davidweininger@comcast .net.