British singer-songwriter Imogen Heap frequently sings against a backdrop heavy with electronic accoutrements -- a creative tack that's been known to trigger critical repercussions. Take Beth Orton, whose beautiful early albums didn't receive the respect they deserved because some reviewers suspected her of hiding something behind the studio touches: subpar lyrics, perhaps, or melodies that wouldn't linger if they weren't tarted up. In the end, though, what matters most is a song's overall impact, not whether it would sound as good when played on an acoustic guitar, and Heap certainly succeeds by this standard. Granted, 2005's Speak for Yourself, her most recent CD, is production-heavy: "Hide and Seek" is a densely layered vocoder showcase, while "Daylight Robbery" contains more than its fair share of beeps and blips. But the interaction between the electro-instrumentation and Heap's beguiling singing lifts tunes such as "Have You Got It in You?" and "The Walk" well above the ordinary. Heap, who shares this date with Zoe Keating, may lean on technology, but she makes it work for her, rather than the other way around.