Straddling the Proscenium and the Pit : Music: Adding maestro duties to an already busy singing schedule has inspired Placido Domingo to do even more.

You’d think an ordinary mortal would find multiple performances of the daunting title role of Verdi’s “Otello” challenge enough for one week. But not Placido Domingo.

Recently at the Metropolitan Opera, he sang Wagner’s “Parsifal” in the afternoon and conducted Puccini’s “Madama Butterfly” that night. So the prospect of conducting a program of Verdi overtures, arias and duets Wednesday at the Dorothy Chandler Pavilion between his “Otello” performances in the same house (on Tuesday and Friday) strikes the 54-year-old Domingo as merely “a wonderful vacation.”

“I think that the conducting invigorates me, if I’m in good health and feeling well vocally,” he said late last week. “It would be different if I was unwell--definitely an extra effort.

“Things come as they come, you know? When the Met planned its season, by coincidence it happened like that: the afternoon ‘Parsifal’ and the evening ‘Butterfly.’ And they said, ‘Placido, both are your performances.’ I didn’t even blink. I mean, I would be worried if it was the other way around--’Butterfly’ in the afternoon and then ‘Parsifal.’ But this way, I thought it was fine; I was not afraid of it. And it went beautifully.”

Domingo has, of course, sung Verdi with many of the world’s great conductors--the ones he lists first are Herbert von Karajan, Carlos Kleiber, Claudio Abbado, Riccardo Muti, James Levine, Zubin Mehta, Lorin Maazel and Georg Solti. “You name it.”

Admitting that he has learned a great deal about conducting by working with these maestri , he emphasized the importance of an operatic conductor who is involved with the music, “beside every beat,” instead of just “a routinier “ who approaches the assignment without feeling.

“There are certain operas in Verdi that speak by themselves,” he said, “for instance ‘Otello’ and ‘Don Carlo,’ with Verdi elaborating his orchestration in extraordinary ways. But one of the most important things for me is to teach the orchestra how to accompany the singers in the early operas where they don’t have the beautiful melodies and they don’t have the beautiful lines. They simply have to play pizzicato sometimes, or just chords under the singers. And that is where I can add a little bit, you know, my help.”

Besides his singing and conducting responsibilities, Domingo is about to become director of the Washington Opera--but he insisted that his duties in the capital won’t affect his role as “musical consultant or adviser” to Music Center Opera in Los Angeles--partly because his most active period in Washington each year will be “always parallel to my Metropolitan time.”

His increasing involvement with heavyweight Wagnerian roles may worry some of his fans, but, again, Domingo said he thrives on variety. “After I finish a run of Parsifals or Siegmunds, I really feel I can sing my Italian operas better,” he said. “I cannot explain why to you, but it really helps me improve the line and everything.

“You know, I have done five new roles in the last 14 months: in (Verdi’s) ‘Stiffelio,’ ‘Guarany’ by Gomes, (Mozart’s) ‘Idomeneo,’ (Verdi’s) ‘Simon Boccanegra’ and ‘Herodiade’ of Massenet. And I am preparing other operas like ‘Le Prophete,’ ‘I Masnadieri’ and also ‘Pique Dame.’

“Tristan--I was almost going to do it next year in Vienna. But I have decided to delay it until maybe ’99. I hope delay, not delete--I don’t know because it’s such a hard one.”

Before that occasion, however, Domingo plans to rejoin Luciano Pavarotti and Jose Carreras for more Three Tenors extravaganzas to delight the multitude and infuriate the purists--perhaps as early as next year, almost certainly in conjunction with the World Cup in France in 1998.

“We are all full of enthusiasm to do it again,” Domingo said. “I am a very serious musician and I dedicate myself, let’s say, to 60 or 65 operatic performances a year. Then I have another 10 or 12 which I conduct. And then I have about 10 concerts which I do in big arenas. And this concert has brought so much to the institutions like public television that needed income at that moment. It practically saved Decca Records in England from bankruptcy plus making so many more people aware of opera.

“So as much as people try to see something negative and curious--and say, ‘This is wrong’--I say, ‘If this is wrong, I will be wrong again.’ ”

Perhaps even more controversial than the Three Tenors concerts (at least in Southern California) is the burning question of Domingo’s nationality: After The Times identified him as Spanish in a previous interview, angry cards and calls claimed him for Mexico.

Typically, Domingo’s response offered something for everyone: “The fact is I’m Spanish,” he declared. “You were not wrong. But I grew up in Mexico and feel very much at heart Mexican. My wife is Mexican, two of my children are Mexicans and I love and adore Mexico without any doubt.”

* Music Center Opera presents Domingo conducting an all-Verdi program Wednesday at 7:30 p.m. in the Dorothy Chandler Pavilion of the Music Center. Tickets: $15-$75. (213) 365-3500.