"We didn't come to see you!" shouted a heckler at the Warner Theatre last night. The remark, one of the more charitable sentiments expressed during the evening, was directed at a magician who, along with several other opening acts and a number of unscheduled delays, turned last night's Staple Singers concert into one long endurance contest.

Not that all the opening acts were without merit. Balladeer Walter Jackson and a vocal quartet called Parris did provide a few entertaining moments here and there. And the comedian who emceed the show was extremely resourceful in placating the crowd. Yet nothing justified the nearly 3 1/2-hour wait for the Staples and when they did perform, it was simply a matter of too little too late.

The blend of gospel, folk and blues elements that has traditionally marked the group's sound is now, more than ever, hidden under a pop veneer. Pops Staple still contributes loping blues licks every now and then, and his daughters can still breathe fire into the songs on occasion. But much of their repertoire -- tunes like "Ease on Down the Road" -- seemed tired and listless. At this point, so was the crowd. It was one long night.