By Bill Brownlee
The Kansas City Star

The 1978 Boston hit "Don't Look Back" is a thunderous declaration about the value of living in the present. More than 7,000 nostalgic fans of classic rock refused to heed the message Thursday as they crowded Starlight Theatre.

The serviceable but flawed performances by Boston and Kansas reflected the challenges faced by aging rock bands and their dedicated audiences. The fans at Starlight witnessed a headlining band that had just one original member, and the opening act was one of the final concerts for its most prominent musician.

The release of Boston's self-titled debut album in 1976 altered the course of rock 'n' roll. In addition to selling more than 20 million copies, the recording introduced the sonic innovations of Tom Scholz. The rock equivalent of the startup chime on an Apple computer, Scholz's influential guitar tone is a technological marvel.

Scholz, 67, effectively re-created his memorably eloquent work on the album's essential hits "Peace of Mind" and "More Than a Feeling" on Thursday. The secondary guitarist, Gary Pihl, also was impeccable. The remainder of the band failed to apply the same level of precision to the familiar material.

Boston's original vocalist Brad Delp died in 2007. Tommy DeCarlo, his current replacement, isn't necessarily a lesser singer than Delp, but his voice is different enough to tarnish the nostalgic glow sought by listeners. The sextet, consequently, often resembled an inspired tribute band.

The oldest material received the biggest ovations during the hour and 45 minutes Boston was on the stage, but the new composition "Last Day of School" demonstrated that Scholz is monitoring trends. The soaring instrumental revealed Trans-Siberian Orchestra's debt to Boston. A habitual tinkerer, Sholtz added several improvements to Trans-Siberian Orchestra's unabashed update of Boston's approach.

Founded in Topeka more than 40 years ago, Kansas also has influenced countless musicians. In April, the fashionable indie rock band Arcade Fire covered Kansas' "Dust In the Wind" at Starlight Theatre. Steve Walsh, the vocalist on the 1977 hit, will play his final show as a member of the band on Saturday. Walsh, 63, bounced around the stage like an excitable teenager throughout his band's hour-long performance.

Although his pending departure wasn't acknowledged, devoted fans aware of the transition savored watching Walsh apply his distinctive voice to the classic rock staples "Dust In the Wind," "Point of Know Return" and "Carry On Wayward Son."