Audiences in general as well as musicians of all specialties--but particularly vocalists--have enjoyed and admired The King's Singers since their first appearances a dozen or so years ago. The degree of ensemble discipline and individual virtuosity for which they are famed might be encountered in the finest string quartets; in small vocal groups it is as rare as it is awe-inspiring.

There certainly was no lack of awe in the Kennedy Center Concert Hall last night, where this sextet of British former choirboys appeared in a benefit for the Alexandria Harmonizers, a barbershop quartet organization that itself has generated no small amount of enthusiasm among its followers.

Avoiding constant superlatives is difficult if not impossible in describing the King's Singers' concert. They really must be heard to be believed. But it hardly would do them justice merely to say that each selection technically was perfect. Their perfection also extended to areas such as phrasing, style, dynamic range, diction, and intonation--areas for which talent and hard work are required in equal measure. Their program also allowed each member ample opportunity to display solo capabilities.

The specifics of this phenomenon of music-making--perfectly-shaped vowels, impeccable diction and flawless intonation--were demonstrated throughout the program. From the light, sparkling madrigals to their reincarnation as 19th-century part songs, and from the novelties of Paul Patterson's Ligeti-cum-Spike Jones "Time Piece" to the introspective "Lamentations of Jeremiah" by Thomas Tallis, no detail of style or interpretation was left to chance. And yet everything seemed perfectly natural. Communication with the audience, whether through music, facial expression or humorous gesture, was direct and constant. By the time they had concluded the program with their own version of Rossini's Overture to "The Barber of Seville," The King's Singers had more than earned a standing ovation and a call for encores.