With their seventh studio album, “The Family Sign,” rap duo Sean “Slug” Daley and Anthony “Ant” Davis continue to shrug off the artificial sounds and heavy production that characterize more popular rap for a raw and distinctive interplay of guitar and piano. The first track, “My Key,” sets the tone of the album, opening with eerie piano strains that lead into down-tempo guitar riffs and echoing vocals resembling an odd mixture of Radiohead and The Beatles circa the late 1960s. The depressed instrumentals carry through most of the album, resonating with deeply personal storytelling.

While Daley unflichingly recites tales of domestic abuse and heartbreak in tracks like “The Last to Say” and “Who I’ll Never Be,” his stoic voice and poorly placed instrumental breaks often leave the tracks lacking in vocal emotion and stacatto.

In an almost-merciful break from sorrowful tones and lyrics, Daley and Davis use tracks like “Millennium Dodo” to explore a gritty perspective on crime, sex and drugs. Though the duo make use of a synthetic beat overlaying bluesy guitar, the sound is more closely related to the harsh beats of early-1990s rappers such as Notorious B.I.G. than to today’s artists.

While “She’s Enough” manages to escape its moody peers into an up-tempo contendedness, Daley also checks his efforts at heartfelt lyrics at the door. In a reflection of the song title, Daley shirks loving coos for shallow descriptors like “She the opposite of selfish/She love housepets/She wanna help kids” that amount to a friendly pat on the back rather than a love song.

Overall, “The Family Sign” makes up for random bouts of aimlessness and Daley’s inexplicably emotionless voice with its embrace of an individual sound seemingly drawn from a mixture of alternative rock, blues and infant rap. Atmposphere may never meet conventional approval, but this lushly narrative album justifies the rap duo’s respected status in the underground.