Tesla seems like a band that can't make up its mind.

Floating somewhere between blues-based acoustic pop and thumping, a-melodic hard rock, they gave a full house in Rec Hall something to cheer about for more than two hours Sunday night.

It's hard to define Tesla's audience: the crowd had its share of headbangers, University students, biker folk, teenyboppers and "long-haired freaky people." The result was a rather tame scene -- people were there to hear the tunes, not out-style the guy or gal in the neighboring seat.

The show, lengthy by usual rock-concert standards, seemed to wear the fans out blissfully, climaxing with the song "What You Give" from Psychotic Supper.

Although the entire group never left the stage, everything after "What You Give" was equivalent to a 40-minute encore, featuring the hit "Love Song" and a feedback-riddled "Modern Day Cowboy," which showed that vocalist Jeff Keith prefers to screech when his singing pipes give out.

"What You Give" was a seamless mix of the "unplugged" and the electric, proving Tesla gets gnarliest when it tames its testosterone level and just comes from the belly. Similar was "Call It What You Want," also from Supper.

In fact, the band's biggest hit, "Signs," from their opus Five Man Acoustical Jam, was given full treatment, as if it has gone from an anthem to being something more tongue-in-cheek.

"Signs" culminated a 30-minute acoustic set that provided guitarists Tommy Skeoch and Frank Hannon a chance to demonstrate their technical proficiency without hiding behind a shroud of battle-axe sound mixing.

Tesla seemed happy with the packed auditorium, giving fans an extra "treat" near the end of the show by covering bits of Led Zeppelin and Steve Miller classics. It was a lighthearted break from their own material -- and simultaneously hinted that even the most popular modern-day rockers have a canon of songs to which they and their fans must pay homage.

Other bits of Tesla's set that scored were "Song and Emotion," a tribute to deceased Def Leppard guitarist Steve Clark, and "The Way It Is."

Opening act Firehouse did a 45-minute set of its high-school-hook-up power ballads, getting fans to flick on their cigarette lighters, but not get out of their seats in some cases. Their hit "Love of a Lifetime" was prototype Top-40 sappiness, a piece of good old American prom music. They came off as hard-working, hard-playing rock and rollers who just wanted to please the audience -- and they did, sort of.