Back when ZZ Top was "that little ol' band from Texas," it offered the basics -- bluesy guitar, gritty vocals and a groove as big as the Lone Star State. These days the band augments its power-trio approach with the latest in electronics and enough special effects to outfit a small amusement park. But despite the high-tech hoopla, ZZ Top still delivers an essentially earthy sound, as the band demonstrated Saturday in the first show of its four-night stand at the Capital Centre.

From the opening, which featured a space-age sphinx snorting a white stage tarpaulin up a golden nostril, to the disappearing act that capped the performance of "Legs," the members of ZZ Top almost seemed props in their own show. Fortunately, through 90 minutes the band's groove reigned supreme.

"Pressure," which started the show, built off a frenetic stomp that all but obliterated the back beat. "Sleeping Bag" added a synth-spiked mechanical pulse to Frank Beard's drums that would have been appropriate in a disco. But the music never quite sounded mechanical, even when -- as on "Gimme All Your Lovin' " -- it was obvious that guitarist Billy Gibbons and bassist Dusty Hill were locked into an arrangement by prerecorded parts.

The magic lay with the band's ability to keep the feel of the music loose, no matter how tightly rehearsed the show. Even the slick electronics on "Legs" and "Sharp Dressed Man" couldn't keep those songs from sounding as down-home and greasy as "La Grange" or "Tush."