Opera workshops: training ground for future Pavarottis

In a larger sense, the sad aria being sung in the former penthouse of an old hotel off Central Park West told a surprisingly optimistic and even happy story. The musty room and the peeling paint were merely a way-stop to brighter things. Rehearsals were under way for a series of workshop or ''works-in-progress'' performances of two promising musical compositions. They were being sponsored by the National Opera Institute (NOI), with a grant from Exxon.

Such opera workshops are blossoming throughout the country, in the wake of what appears to be a US opera boom.

In the past decade, total annual audience attendance nearly doubled to more than 11 million people, according to the Central -Opera Service, an organization devoted to promoting professional and amateur opera.

Part of this jump stems from enlarged performance schedules. In the 1970-71 season, there were 5,286 full-scale performances; 10 years later, there were 9, 683.

In turn, these upward trends have been accompanied by a greater appreciation of contempory American works such as ''Aramantha,'' the opera presented here recently in workshop performances by NOI. A decade ago, less than a third of the operas performed were considered contemporary American works. Today, recent figures show that American operas account for nearly half of the more than 500 operas performed every year.

''Opera is going through the kind of revival that dance went through several years ago,'' says Constance Lehman, program specialist for the Opera/Musical Theatre program at the National Endowment for the Arts (NEA) in Washington.

Opera workshops are becoming recognized as vital training grounds - a kind of operatic ''minor leagues'' - for performers, composers, and lyricists. Successful productions go on to performances by bigger opera companies in more prestigious theaters; scouts seeking new talent attend the shows. Some workshops , such as the established San Francisco Opera Company, are not so much a vehicle to success as an end in themselves.

The Central Opera Service here in New York, which classifies all college and university opera performances as workshops, notes there has been a sizable increase in workshops over the past 10 years.

The current recession has temporarily checked the kind of steady growth in opera performances and workshops that occurred in the '70s. But experts say any decline in growth will be short-lived. One sign of -opera's resiliency is that most large opera companies with annual budgets of more than $100,000 are weathering current economic storms, including slight declines in attendance and in federal and corporate funding. Most large professional companies - now totaling more than 100 - have managed to keep their doors open.

According to the experts, the reasons behind the opera boom have been as varied as notes in an aria. Aside from corporate giving and increased public television and radio broadcasts of opera, many connoisseurs credit the surge in opera appreciation to workshops.

''The nation as a whole is not offering young (or new) artists enough opportunity to create new works and see them on stage,'' says Ellen Blassingham, a spokeswoman for Opera America, an association of large opera companies.

The cost of workshops can vary greatly.

Exxon invested $40,000 in the recent National Opera Institute's workshops held at New York's Park Royal Hotel and subsequently at the Kennedy Center in Washington. That price tag included extensive rehearsal time before the two-week performance schedule of the two new works. Besides ''Amarantha,'' the other NOI workshop piece performed was a musical comedy called ''The Virgin Unmasked,'' with book and lyrics by Sharon Holland and music by Hiram Titus.

Just before the curtain rose at the ramshackle theater at the Park Royal hotel, lyricist Holland summed up the workshop:

''We've taken something that had a lot of potential but was somewhat raw, and we've taken it as far as we can in a month of intense work,'' she said. ''We hope the performances will show us other areas that need changes, corrections, or additions.''