‘73 Sondheim Salute: New and Improved : Stage: A digitally remixed and remastered version of that all-star night of musical theater is being released on CD.

It was an evening to remember--an evening in which the events actually surpassed the hyperbole of the most imaginative press agent.

It was March 11, 1973, a rainy, muggy night in New York City, and some of the brightest names in Broadway musicals had assembled at the Shubert Theatre to honor Stephen Sondheim. The cast list read like an all-star role call of the musical theater: Dorothy Collins, Hermione Gingold, Pamela Hall, Glynis Johns, Larry Kert, Angela Lansbury, Donna McKechnie, Chita Rivera, Nancy Walker--and many, many more.

“I can’t tell you how thrilling it was,” Lansbury said, “to be together with so many of my contemporaries in what still was, at that time, a very healthy musical theater.

“It was because of Sondheim that I went into musicals in the first place. The two songs in ‘Anyone Can Whistle’ that I sang at the benefit concert represented my introduction to musical theater, and they were killers. But it was Sondheim’s encouragement that enabled me to make it, finally, through ‘Whistle’ into ‘Mame’ into ‘Dear World’ and then back with Sondheim to ‘Gypsy’ and, finally, ‘Sweeny Todd.’

“So I was thrilled to be part of the tribute. And the thing that was most striking to me was the sense of the audience’s emotional participation. It was a stirring example of the way the musical theater used to be when there was a total rapport between the artists and the orchestra and the audience.”

The critically praised performance was preserved on a Warner Brothers recording that was withdrawn from distribution within a year--so quickly, in fact, that it has virtually become a collector’s item. This week, however, a digitally remixed and remastered version has been released on a two-CD set by RCA Victor.

It is a significant improvement over the original package with an added number--Pamela Myers’ performance of “Another Hundred Clowns” from “Company”--as well as an expanded version of the full overture.

“When we did this new digital version,” said Craig Zadan, one of the producers of the 1973 concert, as well as the producer of the new RCA release, “we stripped down the tracks, started from scratch and put it all back together again.

“Some of the problems were untouchable: If there was feedback on the original, there’s feedback now. If someone walked away from a mike, there wasn’t much we could do about the dropout of sound. But the digital technology allowed us to come close to re-creating the sound in a way that authentically chronicles the energies of a very exciting evening.”

Recollections of the evening still resonate with unusual potency in the memories of the participants. Alexis Smith, who was in “Follies” at the time, recalled watching her colleagues in action from an unusual perspective.

“We were seated in little gold chairs on the stage behind whomever was singing,” she said. “And it was so fascinating to watch the nervous tension manifesting itself on the backs of the performers--knowing, of course, that out front everything looked just absolutely divine. But everyone was so eager to do their best for Sondheim--who is such a perfectionist, and who tries so hard to stimulate a performer’s best work.”

Donna McKechnie’s choreography for the show--which was produced as a benefit for the American Musical and Dramatic Academy and the National Hemophilia Foundation--took three months to prepare. Since several numbers were done by performers who were not in the original shows, she decided to retain the spirit of the original choreography without duplicating it.

“I wanted to keep the essence, and the feeling tone of the way the numbers had originally been staged,” McKechnie said, “without re-creating anybody’s choreography. And I’m glad I did, especially when I did ‘America’ from ‘West Side Story’ with Chita Rivera--who was so great in the original version.

“But this was an evening without any of the little differences--the tensions and insecurities that can flare up in most companies. And I think it was because everybody was so devoted to Sondheim--who taught all of us the value of the ensemble in the musical theater--and so devoted to making the performance something special.”

The most unanticipated high point of the tribute came when Nancy Walker strolled on stage to sing the ultimate survivor’s anthem from “Follies,” “I’m Still Here.”

For Walker, who did not do the number in the original show, the song touched raw interior feelings.

“Oh, that performance changed my life,” she said. “You have to understand that I had moved to California a few years earlier because I hadn’t been able to get work on Broadway.

“So when I got the call to come back and do the Sondheim show, I went back to New York still quite angry, and I think a lot of that came through in the song.”

Walker had virtually no rehearsal and was having difficulty remembering the lyrics right up to show time.

“Then, when I walked out on stage,” she said, “I remembered it, thank God, and everything came together. It was as if all the years I had worked, and all the things I was capable of doing, suddenly came together into that song.

“I remember feeling a great trembling in back of me, so I just stepped aside and let it go past. And of course, it was my own excitement and the strength of the years that I had worked. I didn’t know if it was going to be received well or not, but it was the only way I could sing it.”

The reception for the number--which is one of the album’s high points--was matched only by the appearance of Sondheim at the close of the show for a brief, almost poignant reading of “Anyone Can Whistle.”

“He’s the only genius I’ve ever worked with,” said Beth Howland. “And when he came out to finish the evening at the piano, I thought I’d have a heart attack!”

But the tribute may have been summed up best by Walker, for whom it was a revitalization in the best Sondheim tradition:

“I walked out of the theater that night thinking, ‘My God, this is the most exciting business to be in!’ ”