Madrid's Zarzuela - where opera is a popular pastime

It's an auspicious evening that begins with strains of Giacomo Puccini's ''Madama Butterfly'' wafting over orange tile roofs into your hotel window. And visitors within shouting distance of the rehearsal studios, which virtually boil with opera all season long, have a pretty reasonable chance of beginning their evenings under such auspicious skies.

The question is, how will an evening of opera in Madrid end?

If a recent performance of ''Madama Butterfly'' at the Zarzuela is any indication, the answer is - not too well.

In a production that all too often provided only a dull cocoon for internationally acclaimed Yoko Watanabe's luminous, touching Butterfly, the Zarzuela showed considerable sophistication, which was unfortunately not matched by equal quantities of inspiration and care. Which came as something of a surprise.

While not one of the world's premier opera houses, the Zarzuela attracts name talent to its stage. Placido Domingo speaks warmly in his autobiography of the years he spent building his career here. And a quick scan of the billboard outside shows an ambitious appetite for producing the great and challenging works. In 1983 ''Lohengrin,'' ''Ariadne,'' and ''Rigoletto,'' together with works by Barbieri and some Spanish composers, filled the house. In 1984 it has been ''Fidelio,'' ''Butterfly,'' ''Tosca,'' Handel's daunting ''Julius Caesar,'' and a handful of other works.

All of this work emerges in an atmosphere of increasing excitement about opera in Madrid, which until recently played second fiddle to Barcelona for such cultural offerings. Going to the opera is all the rage here; and, when standing in line for tickets, one rubs shoulders with students, cabdrivers, housewives, executives, merchants. Their response to the work is said to be uniformly enthusiastic. In the case of this particular production, it was excessive.

The depressing thing about this ''Butterfly'' was not the marginal nature of some of the voices, or the disunity in the pit, but an overall lack of viewpoint about the opera. This was opera staged for the arias, without a cohesive sense of the musical-dramatic core of the work.

Director Horacio Rodriguez Aragon moved characters around with a heavy-handed deliberateness that belied the supple character of Giuseppe Giacosa and Luigi Illica's libretto. Similarly, the scenery was boxish and restricting, providing more of a frame than a landscape for the action.

Only once did the interaction of mise en scene and story line converge into something like dramatic moment: when Cio-Cio-San is mutely confronted with the woman who has stolen her place.

Elizabeth Steiner created a vocally and visually convincing Suzuki, even if she took too mincing a step and too frequently bowed from the waist. Juan Lloveras was simply outweighed by the demands of Pinkerton. Antonio Blancas was more suited to Sharpless.

But no one on hand even approached the radiance of Yoko Watanabe, who moved through the dim proceedings like a firefly in the dusk. She even managed to overcome the loud and inexplicable audience noises that seemed to erupt during the most crucial moments.

One of the more troublesome aspects of the evening was the disorder in the orchestra. The ensemble playing created images of conflict instead of lyrical unity, and some of the solo work was plainly substandard.

All of which was made more mysterious by the fact that Madrid has an ample supply of talented musicians.