Still Together, the latest album from Gladys Knight and the Pips, suggests that Knight could wring a compelling ballad even from consecutive lines in a telephone directory. The material is lightweight, often embarrassingly trite, and, thanks to the writing, production, and arrangements of Van McCoy, reminiscent of disco’s worst tendencies. But Knight’s variously joyous and plaintive vocals consistently rise above the din. She held my attention even during “Love Is Always On Your Mind,” a fluffy formula piece that unquestionably constitutes the album’s nadir.