MUSIC AND DANCE NEWS : AN OPERA WITHIN AN OPERA

The scheme for the production of John Gay’s “Begger’s Opera,” which opens a 10-performance engagement at the Embassy Theatre on Thursday, looks something like this: A group of singers and instrumentalists (members of Opera Theatre of St. Louis) will portray a group of 18th-Century peasants who will become transformed into a group of singers and instrumentalists who will portray a group of 18th-Century peasants.

Complicated? Not really, said set designer John Roslevich. “It’s the old play-within-a-play concept. We see it as a way to involve members of the audience in what’s going on. They’ll see the cast enter with all the props and costumes. They can watch the backstage action--who’s fighting with whom. They can see the ‘actors’ waiting in the wings, the costume changes and all that.”

Roslevich traced this concept back to the first performances three years ago in Clarksville, Mo. “We did the show in an apple shed. There was no theatrical set then. We used the barn as our surrounding. It was perfect. We could hang ropes from the ceiling. . . .

“When we decided to go on tour, we copied what was in the barn originally and added a stairway. It still has a rustic look. There’s even a chicken looking down on things.”

The actual set piece, Roslevich explained, is complete on all sides. “In fact, at most performances, the audience has to enter by walking through the set. Of course, we can’t do that at the Embassy, but I’m sure Colin (director Colin Graham) will have the actors run up and down the aisles and involve the audience as much as possible.”

To emphasize the play-within-a-play feel, one of the characters, Filch, is depicted as also being the composer. “We see him writing scenes during the show, conducting and running around with sheets of music.”

Every possible step has been taken to maintain a ragtag look, Roslevich said. “The props all have different colors and finishes to them, as if this company of performers had picked them up along the way.”

A MYSTERY SOLVED: The Case of the Disappearing Pianist--namely Jonathan Bass--reached something approaching a solution recently. Bass was scheduled to make his local debut at USC on March 24 but failed to show. A crowd of 150, including Times critic Albert Goldberg, waited 30 minutes before a student stage manager stepped out and sent the crowd home. According to William Thomson, dean of the USC school of music, the sponsoring Chopin Foundation apparently mistook the cancellation of a proposed summer Chopin Festival for the cancellation of Bass’ appearance.

Hanna Saxon of the Florida-based foundation was willing to accept the blame. “I was filling in for our departed director so I was not totally informed of our plans with USC. I assumed the (summer festival) cancellation included Bass. People call everything a festival these days.”

Saxon took the opportunity to chide USC for not attempting to confirm Bass’ arrival in Los Angeles or to have an official representative on hand the night of the recital (Thomson admitted to both oversights). “I was going to confirm Jonathan’s cancellation the day after I received the letter,” Saxon added, “but--and I know this sounds like a bad movie--I was suddenly taken ill and had to be rushed to the hospital for major surgery. I feel terrible about this. We (at the foundation) are too concerned with young artists to start them off with a black mark against them.”

And Bass’ feelings? In a letter to The Times, Bass wrote, “Imagine my shock upon learning that a recital of mine, which I had taken to be canceled, had, in fact, occurred--without me. If I could, I would write to every person in attendance that night (to apologize).”

No word from Florida or USC about a “return engagement” for Bass.

BARYSHNIKOV DANCES AGAIN . . . IN N.Y.: Among the principal dancers for American Ballet Theatre’s Metropolitan Opera House season, opening Monday, is none other than artistic director Mikhail Baryshnikov. According to a spokesman for the company, Baryshnikov will appear four times, dancing two pas de deux and two performances of Jerome Robbins’ “Other Dances.”

It is well known that Baryshnikov did not appear at any of the company’s tour dates this year, including the three-week engagement at Shrine Auditorium last month. In fact, it’s been a year since he last performed.

What had not been made public, however, is the fact that Baryshnikov has been suffering from a foot injury, “which (quoting an official ABT release) kept him off the stage for the last few months.” Why was this not told to Los Angeles dance fans who held hopes of seeing him? Why is news of his injury being released now--when he has recovered? The spokesman declined to comment, and Baryshnikov, as usual, was unreachable.

PEOPLE: Witold Lutoslawski was recently presented the first Grawemeyer Award for Music Composition by the University of Louisville for his Symphony No. 3. The work received its world premiere by the Chicago Symphony in 1983, and its West Coast premiere at concerts by the Los Angeles Philharmonic in late November, 1984. The Polish composer, who was awarded a cash sum of $150,000, was one of 204 applicants from around the world.

Composer-conductor John Williams will take his Boston Pops on the road in July for a 15-city, 16-concert tour celebrating the orchestra’s 100th anniversary. One of the stops includes a stop at Hollywood Bowl on July 31.

As a result of a $200,000 bequest by the late composer Remi Gassman, UC Irvine will establish a facility for the study and composition of electronic music. Gassman, who died in March, 1982, assembled the score for Balanchine’s 1961 work “Electronics,” for the Ballet Russe de Monte Carlo’s “Billy Sunday” and for Hitchcock’s film “The Birds.”