More than two decades into its dizzying dance-music career, Erasure [ tickets ] is still good for a surprise or two. The band's latest record, "Union Street," certainly ranks as a major one.

Although these electronic-music pioneers have dabbled before in softer material, most recently with last year's "Nightbird," the fact that Erasure's Vince Clarke and Andy Bell have now unplugged and are traveling the acoustic route makes "Union Street" a very bold experiment. Fortunately, the experiment turned out fairly well for these two mad scientists.

The duo gives an acoustic makeover to previously released 11 album cuts and B-sides, including such oldies as "Spiralling" (from 1987's sophomore effort "The Circus") and "Piano Song" (from 1989's "Wild!"). To be sure, this isn't the acoustic collection that most fans would have designed. The band purposely skips such fan favorites as "Chains of Love," "Oh l'Amour" and "Sometimes"--all of which would have been intriguing, although perhaps too obvious, choices to revisit on "Union Street." Hopefully, however, the band will try out some of those better-known songs during its first-ever acoustic US tour, which kicks off in Nashville in early May.

What makes this collection work, more than anything else, is Bell's voice. The vocalist has always brought true emotion and drama to the lyrics. Without having to compete against Clarke's whirling synth sounds, Bell is able to add new depth and colors to such tracks as "Boy," "Alien" and "Blues Away." A few of the selections sound a bit forced and overly sentimental, but most are very convincing and moving.

In all, "Union Street" delivers a very fresh, and entirely different, look at Erasure's powers of persuasion.