Those following the output of the remarkable French label Alpha should note that this does not contain the art-historical essay included with many of the label's releases, even though it looks for all the world like it should: the cover shows a detail from a painting of Maria Josepha of Austria (it is apparently the younger Maria Josepha, Louis XVI's mother, who is shown) that is included in full on the inside. There is, however, access to an informative essay on Vivaldi and his relationship to the Ospedale della Pietà in Venice, the girls' orphanage where the concertos heard on the album were composed. (Historians disagree as to whether the institution served the poor or the illegitimate daughters of the wealthy who had to be closeted away, however.) The program presents one half of Vivaldi's L'estro armonico, Op. 3, a set of concerti grossi for from one to four violins, at times a cello, and orchestra that were probably Vivaldi's best-known pieces until the Four Seasons exploded in popularity in the 1970s. It's difficult to stand out from the crowd here, but the almost leaderless Café Zimmermann (it has a concertmaster, Pablo Valetti) offers a distinctive approach. This historical-instrument group, as international as its name, gets logistical kudos for bringing together a large group of Guadagnini instruments from the middle of the 18th century. The result is an unusually nice string sound, both lush and bright, in both the tutti (four violins, two violas, two cellos) and the solo parts. The soloists are nicely distinguished from each other in both the playing and the engineering, and the numerous antiphonal effects and intricate textures in the multiple-instruments concerts are very clearly sorted out. One misses a certain crack brilliance that marks the great Vivaldi performances, but at the same time it's good to have a historical-instrument group that plays the music straightforwardly, without the heavily dramatic, quasi-operatic effects of the contemporary Italian school. Sample and enjoy.