THERE ARE a few reasons why the Three O'Clock's revival of the psychedelic pop sounds of the late '60s carries so little impact. While their latest album, "Arrive Without Traveling," shows them masters of the synthesis of commercial song structure and flower power mentality, their sound is so precious and treacly that listening to a whole side is like consuming a box of pralines.

Michael Querico's florid melodies, Mike Mariano's ornate keyboards and a host of classical and oriental motifs do result in some formally impressive and colorful pop constructions. But Querico's adenoidal choirboy delivery projects such unrelieved innocence and wide-eyed romanticism that he seems simply to be recreating a bygone sound and the teenage attitudes that fostered it. There are echoes of the Beatles, Bee Gees and other '60s pop experimentalists in Three O'Clock's harmony-rich style, but there is so much artifice that, after three albums, the band still seems wholly defined by the slim slice of rock history that inspires it.

Salem 66 creates an altogether more personal and imaginative sound on its new six- song EP, "Salem 66." This all-female trio has developed an airy, floating folk-rock style with haunting voices and foreboding guitar lines surreptitiously emerging and then wasting away.

Judy Grunwald's deep voice and Beth Kaplan's more girlish tones create an intriguing harmonic blend underscored by Grunwald's angular guitar figures. When they share vocals and songs, these two create the special feeling of two friends who have read each other's private diaries and are now sharing their secrets with the world.

THREE O'CLOCK -- "Arrive Without Traveling" (IRS-5591).

SALEM 66 -- "Salem 66" (Homestead HSR 002). The Three O'Clock and Salem 66 appear Friday night at the 9:30 Club.