Trevor Rabin could hardly hide his excitement.

"Since the tour started, the reviews are the best we've ever had," the versatile guitarist/keyboardist for the progressive art-rock band Yes said during a telephone call from St. Louis, Mo. "I felt we've prepared more for this tour than any other."Yes, featuring Rabin, vocalist Jon Anderson, bassist Chris Squire, drummer Alan White and keyboardist Tony Kaye, will perform Thursday, July 7, at the Wolf Mountain (formerly ParkWest) amphitheater. Rabin said he is extremely happy with the way things have turned out.

"This tour so far has been the most satisfying," he said. "We are reaching a very mixed crowd of older and younger people, and it's paying off."

Yes, formed in 1968, was the last supergroup to emerge out of London's Marquee Club, which once housed the Who and the Rolling Stones. But unlike those earlier blues-based bands that capitalized on rebellion and attitude, Yes founding members Anderson and Squire wanted to prove rock music could be taken seriously and ultimately lift the music to new creative heights.

By adding the complexity of classical music and jazz to the excitement of rock 'n' roll, Anderson, Squire, Kaye, drummer Bill Bruford and guitarist Peter Banks formed the first version of Yes. And the band, along with other bands like Pink Floyd; Emerson, Lake and Palmer; Genesis and King Crimson, created a new classically progressive rock sound.

The band released two albums in 1969 - "Yes" and "Time And A Word." Both received critical acclaim, but sold poorly. So, to keep the band's lifeblood pumping, the musicians played numerous gigs across England.

Banks left and the band recruited classical guitar virtuoso Steve Howe. With Howe's handling of the electric talisman, "The Yes Album" was released in 1971 and featured the hit "Your Move."

After a successful U.S. tour, Kaye left and was replaced by Rick Wakeman, who graduated England's prestigious Royal College of Music and had played with the likes of Ziggy Stardust himself, David Bowie. Wakeman proved to be a major asset to the band while recording the album "Fragile." His timeless synthesizing twirl can be heard on the band's trademark single "Roundabout."

White eventually replaced Bruford in 1972, just days before the "Close to the Edge" tour, and has remained loyal to the band ever since. He, Anderson, Squire, Wakeman and Howe released an epic two-record set titled "Tales From Topographic Oceans" and took on the world for another full-scale tour.

Patrick Moraz replaced Wakeman for the follow-up album, "Relayer." And in the summer of 1976, a whopping 100,000 people jammed JFK Stadium in Philadelphia to experience a series of sold out "Yesshows."

The next two albums, "Going for the One" and "Tormato," sampled the staple "Yessound" and was received with much enthusiasm. But during those successful times, pressures from the road and creative friction within the band caused major lineup changes. Anderson and Moraz left and were replaced by vocalist Trevor Horne and keyboardist Geoff Downes. This version of Yes released "Drama" in 1980 but broke up after the tour.

In 1982, Rabin, a gifted songwriter in the Los Angeles music community, caught up with Anderson, Kaye and White to record some songs he had written.

"When Chris heard my songs, he immediately called Alan and we all decided to officially put a band together," Rabin said. "Jon heard some of the music and wanted in as well."

After completing the tracks, the five musicians decided to once again call the band Yes. "Since I was the new kid, I was a bit apprehensive about how the audience would take to my material and ultimately how they would take to me, but after the first two shows, I knew it would all work out."

"90125" was released in 1983 and, along with heavy radio and MTV play of the hits "Owner Of A Lonely Heart" and "Leave It," a new generation was introduced to the "Yessound." The album eventually went on to become the band's first No. 1 album.

"Big Generator" and a live album called "The Solos" were released in 1987, allowing time for another rest. In 1991, a mixed effort of all eight musicians that had come and gone through the band's revolving doors saw the release of "Union." "That is my least favorite album to date," Rabin said, though he didn't state why.

The new album "Talk" cut the lineup down to the same five that shot "90125" to the top. Though the album spotlights the familiar sound, it has taken technology to new heights.

"We are releasing a compact disc single that is compatible to CD-ROMs and will allow computer users to interact with scenes while they listen to the music," Rabin explained. "But the most exciting aspect of the tour is the live show's benefit of quadrophonic sound and `Concertsonics' "

Quadrophonic sound - in concert - is an innovative plan to enhance the audio experience, Rabin said. "All reserved seats on the tour will be enveloped in the complete sound system and will hear the enriched sound enhancements. And anyone owning a portable cassette player with an FM dial will be able to listen to the show through the headphones and experience the sound in `Concertsonics.'

"The audience will still be able to experience the show without the 'phones, but by using them, the sound will come through incredibly clear. It's kind of like audio binoculars. It can only be explained best through experience."