TORONTO -- Seeing The Allman Brothers play is like watching a huge, well-oiled machine lumber onstage, rev up and chug into gear. It takes a while to get going, but once it does, it barrels along quite nicely at full speed before winding ever so slowly down.

The current version of the veteran Southern blues-rock band -- which has been operating off and on for more than 30 years -- features only two original members, singer/keyboardist Gregg Allman and drummer Butch Trucks. But the strength of that machine -- and of the late Duane Allman's characteristically clean and soulful guitar riffs, which power it -- make details like who's actually playing seem relatively unimportant.

Despite the fact that Allman sings the majority of songs, the original members tend to defer the spotlight to singer/guitarist Warren Haynes, also the frontman of Gov't Mule, and 22-year-old wunderkind guitarist Derek Trucks, Butch's son. They are both highly accomplished, if less than earth-shattering, blues guitarists, and have mastered the back-and-forth double-guitar style Duane and Dickey Betts used back in the band's heyday.

Along with no fewer than three percussionist/drummers and bass player Oteil Burbridge, Haynes, Trucks et al powered their way through everything from old blues classics to songs from the Allmans' first album in nine years, Hittin' The Note, with the same dogged intensity and good-natured grand standing.

They started slowly, with murky sound and less than incendiary playing, but no one seemed to mind. The crowd, which consisted of men in their 50s wearing tie-dyed band T-shirts and long hair, and men in the 20s wearing the same thing, cheered wildly for favourites like Statesboro Blues, Sweet Melissa, Midnight Rider and Willie Dixon's The Same Thing -- which featured a bass solo by Burbridge -- as well as for new songs like Desdemona, a slow and mournful blues number that was sped up in the middle to showcase a Derek Trucks solo.

About an hour into the set, the band started to hit its stride. Opener Susan Tedeschi -- a blues singer and guitarist who's also the wife of the younger Trucks -- came out to join the guys for Stormy Monday. Tedeschi proved her chops by singing a verse or two and playing a rather magnificent guitar solo.

The fact that even a female guitarist can blend in with the guys onstage, not to mention gain the vocal approval of the bikers in the audience, is proof that nothing can stop the Allmans train from chugging along for the next decade or so.

JAM! Rating: 3 out of 5