Three of the bigger musical personalities to come out of Astral Artists in recent years became a temporary piano trio Sunday afternoon in a concert titled "Encore!" Its significance wasn't lost on the audience at Trinity Center for Urban Life, which was packed despite the sublime weather. The program was what you'd expect from these strong-minded musicians - in that you really didn't know what to expect.

Of course, any concert with violinist Kristin Lee, pianist Michael Mizrahi, and cellist Clancy Newman would program a modern work, and this one - Lonesome Roads by Dan Visconti, who has been tapped by Opera Philadelphia to write Andy: A Popera - has movements that can be performed in any order. But what was Beethoven's less-than-mature Piano Trio Op. 1 No. 1 doing there? Usually that piece is included among only complete cycles of Beethoven chamber music. The encore was the slow movement from Beethoven's Clarinet Trio Op. 11 - how often do you hear that? - with Lee playing the clarinet part.

And, of course, the performances made sense of everything. However temporary, this trio had great compatibility: All are very much to-the-point musicians. They don't dally or play to the audience but go as deep as rehearsal time allows in a medium in which any intellectual or technical slacking off is immediately apparent.

Interpretive zeal, however, didn't trump quality of sound and its expressive possibilities. Mizrahi gave an appropriate Mozartean sheen to the early Beethoven pieces, but not gratuitously, and in ways that suggested he was thinking in the sound world of period instruments, namely the fortepiano. Also, he skillfully showed where Beethoven departs from Mozartean roots with more ambitious (and garrulous) thematic development that he sustained with crystal-clear comprehension. The depth of Lee's tone allowed her sound to begin where Newman's left off - amid their fearless intellectual investigation of the music.

Visconti's trio was inspired by car trips across America, referencing Copland-esque harmonies as a jumping off point for a more personal manner, whether in descriptive effects of cars whizzing by or in his particular vision of loneliness. For me, it was about finding strangeness in the mundane, and how everyday life becomes alien in places that aren't yours.

The Ravel Piano Trio, the biggest piece of the program, has rarely felt more modern. Tempos were fast. Collective tone colors weren't soft and dreamy, with a nervous edge that wasn't at all perverse but was taken from obvious cues in the music that others bypass - in a vision of this composer that would never have him discussed in the same sentence as Debussy. This Ravel wasn't black and white - but could have been, in light of the performance's rigor. Because these musicians have a keen sense of sound, there's no way the performance would turn into an anti-sensual experience. So singular was their approach that you wanted to download the concert immediately - and hope this temporary trio becomes at least semipermanent.