The members of the Catalyst and Harlem quartets perform together. Photo: Matt Genders Combining magnificently into a single forceful octet, the Catalyst and Harlem quartets reached a climax at this concert’s conclusion with Mendelssohn’s classic in the genre. Presented by the Philadelphia Chamber Music Society, the group boasted elegance, reverence and rich timbres in the opening movements. In the ticklish Scherzo I wondered, ‘How can anyone not like this music?’ And the final Presto roared like a vintage convertible, cruising down the highway. In the spare formality of Philadelphia’s Benjamin Franklin Hall (for a Covid-limited audience, with the performers wearing masks), the ensemble’s luminosity was evident from the opening work, Jessie Montgomery’s Strum (2006, rev.2012). Amid luscious chords, strumming eventually takes centre stage, and the warm vibe continues in an exuberant race to the finish line.