With awesome power and vitality, British superstar rockers "The Who" pounded the Spectrum's SRO audience last night with a show combining the raucous roots of rock 'n' roll with the complexities of today's progressive pop music.

The true originators of heavy rock, the four-man group progressed through various stages following their primal beginnings in the era of the British rock invasion. Best known for their rock opera "Tommy", The Who set new commercial and artistic standards with their mixture of 4/4 rock in a legitimate format. Continuing as pacesetters into the 70's, they have produced several more landmark works, each one increasing their popularity and stature.

In concert appearances in recent years they have concentrated on the musical direction of the particular moment, depending on "Tommy" and the later "Quadrophenia", while generally ignoring more basic and invigorating material.

Opening with the 1965 classic "I Can't Explain," they instantly set a high energy, vibrant tone for the evening's set, with guitarist Townshend jumping and cavorting as he set down the familiar rhythm line. Then to "Substitute," with singer Roger Daltry glamorously out front wailing away, aided by the tight harmonies of Townshend and bassist John Entwistle.

On the show went, with each member of the group giving what seemed to be the performance of his career. Drummer Keith Moon led the group along with the volatile Townshend, the whole evening. The Who hardly seemed like a band over 10 years old.

Mixing selections from "Who's Next," "Tommy," their new album, "Who By Numbers," and an array of early material, they produced a perfectly paced set, satisfying both to themselves and to their audience. Outstanding were "Behind Blue Eyes," "I'm Free," "Magic Bus" and "Squeeze Box," all performed like clockwork. Selections from "Tommy," notably "Pinball Wizard" and "See Me, Feel Me, Touch Me" were more relevant than in past shows, and were spectacularly complimented with the first use of laser beams at the Spectrum.

Along with the superb music, Daltry's friendly patter, Townshend's acrobatic energy, Moon's clowning, and Entwistle's deadpan posture added to the special aura of The Who.

The last date on their present tour, their show was a spectacle on the grandest scale, showing rock 'n' roll to be an art form on the highest level of contemporary culture. Let it be said that The Who gave Philadelphia its best pop concert of the year.