Richard Wagner's ''Der Ring des Nibelungen'' on television used to be only a pipe dream. Now it is bold, vivid reality, thanks to UNITEL, a TV production company in Munich, and WNET, New York. ''The Ring'' will be seen on the PBS ''Great Performances'' series on the following dates: ''Das Rheingold,'' Jan. 24 . ''Die Walkure,'' Act I - Feb. 21; Acts II & III - Feb. 28. ''Siegfried,'' Acts I & II - April 11; Act III - April 18. ''Die Gotterdamerung,'' Act I - June 6; Acts II & III - June 13. (It is important to check local listings for times and for possible variations in dates.)
''The Ring'' about to be televised is the controversial Patrice Chereau staging first seen at Bayreuth in 1976, when the famous operatic tetralogy turned 100. Not for Chereau the craggy rocks, the horn-festooned Valkyrie helmets and steel armor, and other such trappings traditionalists would have expected. Rather, it is a rethinking, an updating, stressing the allegorical rather than the merely narrative aspects of this work.
Chereau wanted to bring to life the issues Wagner was addressing when writing this work - the corrupting influence of money, the abuses of absolute power, the nature of love and of hate, and so forth. Chereau sets the first scene of the first opera in the tetralogy, ''Das Rheingold,'' not in the river Wagner envisioned, but in a hydroelectric power station, circa 1880. The Rhinemaidens are prostitutes, Mime is a ghetto Jew, Wotan is Wagner himself, in Victorian dressing gown.
To date I have pre-screened ''Rheingold'' and ''Walkure'' all the way through. Any objections I thought I would have to such apparent tampering with Wagner's instructions have been swept away by the sheer theatrical power of the production. Chereau is out to make his points, but not at the expense of the spirit of Wagner, but rather with believable figures in believable situations.
Indeed, it is the credibility of the characters as very real human beings that comes soaring through, from the malevolent Alberich right up to the hectored, anguished Wotan. And throughout the first two operas, I was constantly reminded of the epic sweep of the unfolding drama.
The viewer will be struck right off by the visual beauty of Richard Peduzzi's sets and Jacques Schmidt's emphatically Victorian costumes. Everything is richly photogenic, with TV director Brian Large giving the viewer the best of all possible close-ups and a full sense of the scope of the sets on the huge Bayreuth stage.
Mr. Large is almost never guilty of intruding his ideas of what should be seen at any given time. Rather his works serve to bring the scale of so large a production down to managable TV-screen proportions. How sad it is that the broadcast schedule divides ''Walkure,'' ''Siegfried,'' and ''Gotterdamerung'' up into two evenings each, and spreads the entire ''Ring'' out through June!
The cast assembled is exceptionally photogenic as well. And they all act superbly. Imagine a svelte Brunnhilde, an elegant, handsome Wotan, a Siegmund who can appear on a stage bare chested without embarrassment. And each is so deeply into his or her role that one never loses the focus of the drama at any point. They move unusually well on sets that offset that motion brilliantly. At the end of the first act of ''Walkure,'' one sees spring greenery and a moonlit night. At the end of the opera, the fire appears with theatrical magic.
There is one irony about the entire event, however. Wagner was trying to usher in a new operatic order with his works. This centennial production also serves to usher in a new order of which Wagner would clearly have disapproved. He wanted his operas to be sung beautifully, and virtually none of the singing in this cycle is up to the standards one would have expected from Bayreuth. Even a mere 15 years ago, Bayreuth - whose standards have been plummeting in past decades - had better singing than this program offers. Donald McIntyre's Wotan is just about the best sung of the principals. Gwyneth Jones's Brunnhilde is about the worst, with the remainder filling in the spread between those two extremes
Peter Hofmann is as good looking a Siegmund as ever there will be, and he sounds quite fine, though the voice lacks the heroic heft that used to be a minimum requirement in the role. Jeannine Altmeyer, the Sieglinde, has a large voice used adequately, and she looks suitably young (a tangible plus), but there is simply no connection in her work to the passion and depths of emotion a singer has to underline if the role is to have the impact it demands.
Pierre Boulez elicits stunning playing from the Bayreuth Festival Orchestra, and the approach to the music is nowhere near as eccentric as one had been led to believe from preliminary reports. This Wagner moves with majesty and power almost all the way through.
Sadly, if ever there were a TV event that highlighted the pitiful state of television sound, this is it. So be sure to turn on your FM radio (stereo if you have it) to get the full simulcast flavor of the event. Branca's Third Symphony
The Brooklyn Academy of Music, known locally as BAM, has been presenting an ambitious series devoted to ''New Wave Composers,'' this season beginning with Steve Reich and ending with Laurie Anderson. Be it good, bad, or indifferent music, BAM offers the serious new-music lover a lavish chance to hear something most traditional concert halls would never deign to offer.
This past weekend, Glenn Branca has been presenting the world premiere of his Third Symphony (subtitled ''Gloria''). On stage were a full set of drums, as well as a quantity of instruments Mr. Branca has designed for the sonic explorations he undertakes. They are mostly boxes with steel strings that are hit with small mallets in dulcimer style. Others are some sort of keyboard creation that create ominous, almost gamelan-type sounds.
Putting it all together, amplified and miked, makes for a formidable sound. Unfortunately, Mr. Branca does little with these sounds, content merely to make thrashing, crashing noises that will generate their own set of special overtone clashes within the amplification.
Mr. Branca, who comes from the world of rock music, has been receiving a good deal of attention of late for his ability to create sound walls of truly shattering force within the context of his musical quests. Actually, on the basis of the new work, the term should not be ''quest'' but rather ''meandering.''
Not that there were not some moments of beauty (usually the quieter ones) or sheer visceral impact. But, like so much rock, a primitive evocation of the primordial seems to be the be-all, end-all; the louder apparently, the better.
I am assured by Branca fans that his earlier experiments using electric guitars and such other instruments had a peculiar beauty and fascination. Little in Symphony No. 3 evoked anything much at all. One trusts that he will emerge from the roar of the amps to fulfill the promise his followers fully believe he possesses.