Koji Attwood's 10 minutes of great substance arrived like a bolt of genius Sunday afternoon in a program otherwise offering fluff.

It was high-quality fluff, to be sure - Rossini, Respighi and Martucci. But when Attwood, the pianist who has been taken under the wing of Astral Artistic Services, played three Scarlatti keyboard sonatas, everything else on the program shrank in stature. The pieces themselves (K. 11 in C minor, K. 101 in A major and K. 27 in B minor) are marvels of virtuosity, a quality realized elegantly by Attwood. He was stylish and wonderfully fluid. But he also established a sense of organization to what can sound chaotic, making connections between the quick runs that start and end suddenly. His was a performance that was both deeply thought and felt.

Attwood was also pianist in Martucci's Piano Quintet in C major, the major piece on Astral's all-Italian program at the Trinity Center for Urban Life (sponsored by the Musical Fund Society). The pianist and Koryo String Quartet made about as convincing a case for this piece as any group could, and it is very pretty music. In fact, one could listen to it for hundreds of bars on end without being bothered by a single important thought. The melodies are accomplished in creating release, but not so strong on tension. A flatness settles in after a while. Still, the strings were cohesive and expressive, and, in the case of violist Jonathan Vinocour and cellist Earl Lee, capable of great emotion in their rich lower registers.

I have a soft spot for Respighi's chamber works (yes, he wrote pieces other than the frequently done large-orchestra tone poems), and was grateful to be reminded of his powers of intimacy in Il tramonto (The Sunset) for mezzo and string quartet. It's gentle, atmospheric music with Puccini-like vocal writing and a touch of Schoenberg's Transfigured Night about it. Mezzo Leslie Johnson was warm and commanding, as she was in Rossini's La regata Veneziana for mezzo and piano.

Contact music critic Peter Dobrin at 215-854-5611 or pdobrin@phillynews.com. Read his recent work at http://go.philly.com/peterdobrin.

Next Astral concert: Violinist Ayano Ninomiya, cellist Clancy Newman and pianist Claude Frank perform Mozart, Beethoven and Schubert March 18 at 3 p.m. at the Trinity Center, 22d and Spruce Streets. Tickets are $5 to $16. Information: 215-735-6999.