Saturday's Bluegrass '77 concert, split into afternoon and evening shows at the University of Maryland Cole Field House, was a barely adequate concept ineptly realized.

The idea of bringing together eight of the top bands in bluegrass is not particularly original. Outdoor festivals running from May to October have done just that for years.

But they also offer a warm ambulance, something that probably will never occur at the cavernous Cole Field House. This was especially evident at the afternoon performance when 2,000 patient bluegrass fans sat scattered among 12,000 empty seats, straining to hear some frustrated players trying to overcome a totally inadequate and misused sound system.

A similar effect could have been gained by turning on a cheap radio in one's bathroom, leaving the door slightly ajar and wandering two rooms away. Under such conditions, bluegrass had little chance to show off its finer points, even the bands led by such legendary musicians as Ralph Stanley, Lester Flatt and Bill Monroe, the "father of bluegrass music."

Because of the horrid sound system, it was frequently hard to discern the normally stellar performances of instrumentalists like fiddler Kenny Baker and banjo-player Butch Robbins of Monroe's band, dobro-player Mike Auldrige of the Seldom Scene and banjo-players Kenny Ingram and J. D. Crowe of the Nashville Grass and the New South, respectively. Only occasionally did their prowess pierce through the weakness and fuzziness of the speakers.

Vocally, things were a bit better for those who were willing to strain to hear the mercurial harmonies of the Seldon Scene and Country Gentlemen. The sets were generally too brief, tending to either lethargy or hurriedness.

In many ways the entire presentation was embarrassing and distasteful. The 6,000-plus fans scheduled for the evening concert may have suffered less, but the afternoon audience paid the full price.

When Bill Monroe ended his set, he called up musicians from the preceding band, many of whom had played in his Bluegrass Boys at one time or another. They came but their cumulative talents were squandered in a mass of confusion. It was that kind of show.