There's a deceptively diminutive quality to singer-songwriter Emma Louise Niblett, the Nottingham, England, native who makes such a strong debut with Sweet Heart Fever (Secretly Canadian). She navigates her fragile, folk-tinged melodies--some of which, like Kurt Cobain's performance of "Where Did You Sleep Last Night," draw on the primordial despair of the blues--with a beguiling hesitation, as if something dark and elusive were lurking just out of sight. Her deliciously dusky voice recalls Chan Marshall of Cat Power with its wonderfully parched edge, but it's closer to Polly Jean Harvey's in its melodic precision and confidence, tracing song contours with a gorgeous delicacy mirrored by her simple strummed guitar. Niblett's trick is to keep both elements perpetually on edge; they seem ready to explode into chaos at any moment, but the tension is never quite released. A press release claims that her live performances are filled with "Sonic Youth-like" guitar freak-outs; that band's influence is certainly evident in the dissonant opening chords of "Miss My Lion" and the oddly distended sequence of riffs on "So Much Love to Do," but nothing on the record suggests that sort of unhinged energy. Even when drummer Kristian Goddard lays down a walloping beat on "Big Bad Man," Niblett's guitar patterns are reserved, almost singsongy, and her humorous lyrics undercut any implied danger ("Big bad man, big bad man / I'm going to cook you some real food"). She'll play an in-store on Wednesday at Reckless Records in Lakeview; that evening at Schubas she'll be joined by drummer Ben Swanson, who also performs with the Post on the same bill. Wednesday, February 20, 6 PM, Reckless Records, 3157 N. Broadway, 773-404-5080, and 8 PM, Schubas, 3159 N. Southport, 773-525-2508.