For the King's Singers, it all looks so easy. They come on stage, they woo a large and appreciative audience (usually at capacity) with a series of smooth and catchy songs, many of them witty and urbane, and then they retire to their dressing room with the sense of a job well-done, a crowd well-pleased.

Well, some of that we may be sure is true - the part about wooing and winning an audience. But the rest may be a slight exaggeration, because the singers are well-nigh perfect at what they do, and perfection is never easy.There's more to that smooth stage appearance than meets the eye: the long search for just the right repertory and arrangements, the many hours of practice to achieve the nuances, the split-second timing that puts their act in a class by itself. The Singers always please with their unique blend and range, from high counter-tenor down to low bass, for a compass that gives them added scope, far exceeding ordinary quartet singing. And their programs can always be counted upon to encompass the unusual and refreshing.

Wednesday's program opened with a little suite of Canadian folk songs, arranged by the ensemble's tenor, Robert Chilcott. In "A la Claire Fontaine" he positioned the melody above an accompaniment of mouth noises that suggested a bubbling fountain. "L'habitant de Saint-Barbe" with its folding in of added parts and voices was followed by a tender, sad little love song, "She's Like the Swallow," and all ended with a rollicking jig, "The Feller from Fortune."

German madrigals of the Renaissance proved to be no match for their Italian or British counterparts, though the songs of Hans Leo Hassler were pleasant enough, and Isaac's "Innsbruck, ich muss dich lassen" contained heartfelt pathos, perhaps inspired by the composer's own departure from that fair city. Both singers and audience had the most fun with Lassus' "Ich hab' dich lieb," a declaration from a lover afflicted with a cold, and interrupted by barrages of sneezing and coughing. Was this Lassus' idea, or the King's Singers? One suspects a certain amount of sabotage.

The "Nonsense Madrigals" of Gyorgy Ligeti, with wonderful texts by William Bright Rands and Lewis Carroll, inspired high anticipation. But they were a disappointment on two counts, since the settings were too complex, the melodies scanty and unvocal-sounding, and the words set in such a way that even the most avid listener must have difficulty in distinguishing them. A music hall style of setting for such material would be more enjoyable.

Part songs of British composers fared better, including Gerald Finzi's lovely "My Spirit Sang All day," the wistfully simple "Little Green Lane" arranged by Lovatt, and the gentle "Blow Away the Morning Dew," arranged by Morris.

But it was with selections from the lighter side that the Singers aroused their audience, including a splendid arrangement of "I Can't Sit Down" from Gershwin's "Porgy and Bess," "A New Day," dedicated to Weber State on becoming a University, "The Flight of the Bumblebee" with many descriptive mouth noises, and Billy Joel's "And So it Goes" sung with simple sincerity.