What better way to conclude the first day of a festival than with an eclectic programme in a splendid space? Adorned with chandeliers, portraits and reproductions of Robert Adam's 18th-century plasterwork, the Plaisterer's Hall couldn't help but impress; fitting, then, that the Danish String Quartet should be the ensemble to perform in this space.

The concert saw the ensemble getting back to their Scandinavian roots with Nielsen's String Quartet no. 2 in F minor and a selection of arrangements of Nordic folk tunes (which feature on the ensemble's most recent disc, Wood Works), with Beethoven's Tenth String Quartet completing the programme. The most impressive aspect of the ensemble was the way in which its interpretations were considered and steadfast but without losing any vitality. Equally admirable was the bond between members: passages in which two or more players were in harmony or octaves were rendered immaculately, and the clarity of texture which they brought to the music was particularly effective in the Beethoven.

Nielsen's Second String Quartet was completed when the composer was just 25, and shows the composer reconciling a Romantic musical heritage with the folk influences of his youth as he was discovering his own voice. Bold harmonic jolts interrupt at unexpected moments as the folk influences gradually emerge, bringing with it an ominous darkness.

The quartet's athletic sound suited the vigour of the music, with surges of intensity to highlight the transitions in Nielsen's outer movements. The sinking harmonic progressions in the second movement were given warmth and breadth, balancing spaciousness and intimacy. The folk influences were most clear in the playful third movement, with cellular repetition and irregular rhythms, before the finale reconfigured the gestures of the past. Violist Asbjorn Norgaard's alluringly creamy tone was a particular highlight, while cellist Fredrik Schoyen Sjolin provided strong support throughout.

The quartet lent Beethoven's Quartet no. 10 “Harp” a pleasing clarity and a light touch. The first movement's exposition gradually blossomed, the players bringing off the melodic lyricism with a radiant joy. The performance was crisp and neat – occasionally too neat, as greater flexibility of tempo would have transformed the second movement – with pleasing phrasing and a lovely rise and fall. The blistering scherzo had passion and urgency, with terraced dynamics taken to the extreme, before the players characterised the variations in the finale with humour, emphasising the contrast between affects. As with the Nielsen, leader Frederik Øland's sound occasionally lacked richness and his intonation occasionally wandered; however, these were relatively minor concerns in a performance of this calibre.

The second half brought a more festive mood. Rune Tonsgaard Sørensen replaced Øland as leader for a selection of Nordic folk song arrangements, which ranged from a wedding suite to “rock and roll from a little valley in Norway”. The arrangements were most effective, embedding the songs' fruity harmonies into evocative textures which alluded to viol consort and organ. Many of the pieces contained a rhythmic groove – a rhythmic hook which provided a firm foundation for the melodic ideas.

While the quartet's classical training still took precedence – individual phrases in a waltz were neatly rounded off with diminuendi – a rawness underpinned the playing. The ensemble's enjoyment was infectious, and their flair couldn't help but bring a smile to one's face – definitely a quartet to watch.