Atlanta soul retrolutionaries Joi and Dionne Farris do things the old fashioned way: raw, full of ardor, completely from the heart. Their debut albums reject the synthetic, straightening-comb funk that has cheapened R&B, blowing the genre out to its heartfelt origins. These two sistas with voices are fully aware that spontaneity takes place in the present tense.

Joi is a smoldering seductress with...