ABOUT A YEAR ago when Telarc, a relatively obscure Cleveland firm, released the first commercial digital disc, reaction was just about unanimous about the remarkable qualities of this new sound process, born of computers and information theory.

But in most cases the plaudits were dampened with expressions of doubt by major figures in the industry about this first step toward revolutionizing the way sound is reproduced, with its relative freedom from audio distortions that originate on disc and tape surfaces. Digital sound sounded grand, and it had been long accepted by many as the eventual "wave of the future," but given the dolorous state of the economy and of the record business in particular "was the public ready for it?" Such squeamishness toward new technology was further compounded by the recent experience of those companies that had invested heavily in quadraphonic sound only to see it turn into a sales fiasco.

Of the major firms, only British-based London resolved to join the small companies in taking the risk. It was a decision that within a few months was vindicated by the high standings of London's first four releases on the trade publication charts. Last January's New Year's Day waltz and light opera concert by the Vienna Philharmonic under Willy Boskovsky was released on two records (London: LDR-10001-2) and quickly soared to first place on Cash Record's classical list and third on Billboard's.Even Telarc's first release, despite that company's limited marketing resources, has held steadily on the list for months.

One result has been to throw most of the competition into a scramble to catch up. Instead of emerging as a risky limb that seemed perilous to mount, digital recording has shown potential to give new life to a $4 billion industry now faced with faltering sales and staff cuts after a quarter-century of uninterrupted growth. This month RCA initiates the plunge into digital of London's major American-based rivals with a glittering record of Bartok's Concerto for Orchestra by Ormandy and the Philadelphia Orchestra (RCA: ARC1-3421). Taped only last April 16 after RCA decided to launch its digital issues with bang, the Bartok uas rushed into print within about three months. It should be in local shops any day now, and RCA is sufficiently pleased with the product that the company plans to record all its future Philadelphia Orchestra releases in stereo.

As other companies join the trend the previously slender digital repertory is to be enriched this season by such discs as: the first digital opera, Beethoven's "Fidelio" with Sir George Solti conducting the Chicago Symphony and soprano Hildegrad Behrens; Prokoviev's Fifth Symphony with Bernstein and the Israel Philharmonic; several works taped by Bernstein and the New York Philharmonic during their Japan tour last spring, and an Italian opera recital by tenor Luciano Pavarotti.

Both Columbia and Angel as well would be releasing their first digital discs now but for editing problems they are having with the new technology. Each company has considerable numbers of digital recordings in stockpile. "We would like to get some of the records out before Christmas," said Joseph Dash, Columbia's vice president for development, "but we won't unless it's a super quality disc." As London's American classical promotion manager Dick Bungay observed, "We simply can't afford to let through an inferior digital release. The public would be better off with a standard stereo recording of the same thing, (rather than) end up hurting the digital market."

Classical records still predominate in the digital market on both sides of the Atlantic, though preliminary trials are underway by several rock specialists -- including Warner, Motown, Casablanca and possibly A & M.

Two major European-based classical companies, Philips and Deutsche Grammophon, are the most conspicuous remaining holdouts on the current digital developments. Nancy Zannini, an American representative working for Polygram, the umbrella firm for both companies in this country, traces this determination both to their confidence in the existing product and to their confidence that Philips is ahead of everybody else in developing the full fledged digital system that will eventually supplant today's hybrid disc."We think that our pressings, all of which we fly here from plants in the Netherlands and Germany, are regarded by record buyers as superior in quality to those made here, and that these speak for themselves. We simply don't feel the need to go into this intermediate phase along with the competition. Remember, we never went into quad either."

The existing commercial digital recordings are labeled "hybrid" because "the digital aspect of it begins at the microphone and ends at the cutting lathe," as it is described by Thomas G. Stockham, president of Soundstream, a Salt Lake City sound engineering company that has played a major role in developing digital equipment and has handled the work on many of the records that have come out recently, including the RCA Bartok disc. The full-fledged benefits of digital technology will not come until the existing tapes are matched by digital play-back equipment in the home, so that the technology will fully extend beyond the lathe, without interference, directly to the listener. If the Compact Disc System Philips modeled this year in New York is the model, digital playback equipment will use a record smaller than a 45 and put it on a turntable where it will be scanned by a laser. Since tone arm and record will not come in contact and for the first time records will require no stylus, the life span of the record will be indefinite. As Stockham puts it, "Digital recording will be to sound as writing is to equipment. Digital recordings could exist for centuries in their original quality. Zannini predicts that the full system will be on the market "in about five years." Officials of other companies predict that it will come much more slowly.

Just how much better is the sound on today's digital record? Since only several dozen releases have yet come out, it is impossible to generalize beyond certain specifics. And because there is so little to compare anything to, it is impossible to say whether certain sonic idiosyncrasies are the work of the interpreter or the engineer. The high frequencies of the Bartok, those piercing highs from the winds, the percussion and the strings that often give the work its urbane, ironic bite seem more bland than often heard. But based on years of hearing Ormandy conduct the orchestra live, this is clearly the kind of sound that Ormandy often favors. So instead of being a warped facsimile of the original performance, this one may instead be unusually accurate. Likewise, the louds and softs are less breathtaking than one might expect. But, when followed with a score, obscure details that often are lost come through quite clearly. But they don't jump out at you -- just as they would not do so in the concert hall. Ormandy himself has described the sound glowingly, an encomium that should speak for itself.

The typical characteristics of digital sound blaze forth more strikingly in the Vienna Philharmonic concert, dominated by Strauss waltzes, polkas and matches performed before an audience in the acoustically mellow Musikverein hall. The timbres may be less varied than in the Bartok, but Boskovsky gets the gutsy most out of them. And the dynamic range of digital sound could hardly be more strikingly demonstrated. The 18 works are full of rousing rhythms and surging climaxes. And the concert is finsihed off with a stirring whirl at the Radetzky March with the audience clapping in time to the music. Some have objected to the audience sounds, but as a display piece for the sonic possibilities of digital discs they add a delightful extra dimension to the experience.

Yet another example of its special possibilities comes in the perfectionist pressings of Telarc. Perhaps the most spectacular yet is the new Moussorgsky record by the Cleveland Orchestra under Lorin Maazel (Telarc: 10042). Such major organizations rarely record for the small companies, but as Bob Uoods of Telarc explains it, "The orchestra already records for both Columbia and London but it has no exclusive contract. Maazel heard our first record and wanted to work with us. Further, it should be noted that my wife is an orchestra player." A recording of the Tchaikovsky Fourth Symphony is on the way as well. On the Moussorgsky those time-honored audio showpieces, "Pictures at an Exhibition" and "A Night on Bald Mountain," are recorded with a clarity of texture and dynamics that are indeed remarkable.

Given the success of these conventional pressings from digital tapes, one wonders if the public will not simply choose to stay with them for the next decade or so rather than follow Philips all the way and have to buy a new turntable. Also, will the sound on the all-digital recordings be marginally superior to the hybrid digitals or will it be so decisively better that the public will readily make the additional investment? Also, is not the public in danger of getting caught in the coming years in a war between conflicting and incompatible systems much like the fruitless war between 45s and 33 1/3s that launched the LP era? London's Bungay answers, "Our future will be in digital." But he does not say when and in what form. That is something no one can say with assurance now. One thing is sure, though, digital recording is no longer just a laboratory phenomenon of interest mainly to audiophiles.