The current version of the Temptations, which stopped at Wolf Trap recently, contains two of the original backup singers but neither of the lead singers who gave that Motown quintet its classic sound in the '60s. The two original lead singers, David Ruffin and Eddie Kendricks, appeared at Constitution Hall Saturday night, and even if they don't own the legal right to the Temptations' name, they own that distinctive Temptations sound.

Both of the very tall, very thin men did a solo set of their post-Temptations hits, but that only underscored how much Ruffin's gritty tenor and Kendricks' ethereal falsetto need each other. When they reunited for a medley of Temptations classics, the blend of their voices obviously delighted them as much as it did the crowd.

A preceding set by the Impressions featured two of the Chicago soul group's original backup singers (Sam Gooden and Fred Cash) but neither of its illustrious alumni: Curtis Mayfield and Jerry Butler. Smokey Hampton proved an able substitute for Mayfield's silky falsetto on "Keep on Pushin'." Butler had been scheduled to perform, but due to illness he was replaced by another veteran Chicago group, the Chi-lites, whose original lead singer, Eugene Record, led them through a convincing version of "Have You Seen Her?"