Even Piffaro's strongest believers would not expect the Philadelphia Renaissance band to make good on the title of its concert, "Drive the Cold Winter Away!" particularly in venues that happen to be hard-to-heat churches. But the solstice program was such a witty alternative to usual holiday fare that wearing wool socks was hardly a prohibitive admission requirement.

The guest artists, soprano Laura Heimes and tenor Philip Anderson, were by themselves good reasons to catch Saturday's concert at St. Mark's Church (repeated Monday at Princeton's All Saints Church). The best part? Believe it or not, "Deck the Halls."

The drive toward historically authentic performances that revolutionized Bach and Handel yielded dramatic results when turned on certain carols. That "fa-la-la" stuff originally seems to have been short interludes for instrumental improvisation. And in the version done only with Christa Patton's harp accompaniment, "Deck the Halls" was thoroughly reimagined and improved. Translated from the Welsh, the alternative lyrics contain no great revelations, but showed how a quiet, charmingly simple song that says, "Look forward to the future, don't grieve the past" could be turned into something far more boisterous.

In general, the concert evoked a pre-electricity society dealing with December darkness, which is more pervasive in the British Isles than here, and demanding that the music have a strong medicinal element. Spoken interludes were given in an archaic language that sounded like Scandinavians speaking broken English. In such a context, the simple directness of oft-heard items such as "I Saw Three Ships" or "Drive the Cold Winter Away" functioned as a sweet pill in bitter times. One alternative version was less successful - "Greensleeves," cluttered with a lot of words about the old year having fled, distracting from the innate nostalgia of that great, timeless melody.

Both soloists managed to sound other than American; Heimes seemed almost Mediterranean. In pieces that use the same music for different verses, she avoided treating the words with art-song specificity in lieu of broader, coloristically seamless strokes. Anderson has the taste and flexibility of English tenors at their best, with a particularly handy upper range.

Part of the concert was devoted to dance (one way to get warm) and added texture and complication to the program. Some pieces were from a book of Flemish dances, others from more melancholy Britain. Such performances had maximum sound variety, thanks to Piffaro's ability and penchant for quickly changing instruments. Ensemble problems noted last season were absent, reminding that Piffaro is one of the best ensembles of its kind - and that's more than playing instruments well. Who else could achieve such a mellow blend of three bagpipes?