When formed 15 years ago, Megadeth was one of the new breed of no-sugar-added metal bands that preferred the Sex Pistols' confrontationalism to Def Leppard's commercialism. From the thudding tracks that open the new "Risk," there's no reason to suspect that the quartet has changed its tunelessness. Unlike most contemporary rock CDs, however, this one gets more melodic as it continues. By the time the band gets to the penultimate "Time: The Beginning," the guitars have even come unplugged.

That's not to say that singer-songwriter Dave Mustaine has adjusted his attitude. Titles like "Prince of Darkness" and "Crush 'Em" offer the customary celebrations of violence and evil, and the singer opens the album as if he's auditioning for one of Vincent Price's '60s horror-movie roles. But such subsequent tracks as "Breadline" and "I'll Be There" take a turn toward modern rock, and "Seven" sparkles like the Sweet's meld of metal and glitter. "Risk" isn't a complete capitulation to the forces of accessibility, but the Prince of Darkness may think twice about renewing Mustaine's membership in the Hellfire Club.

DDT records for the Music Company, a label founded by Metallica's Lars Ulrich, but there's not all that much metal reinforcing its sound. On this Vancouver quintet's first full-length release, "Urban Observer," the musicians bounce energetically from ska-punk to hip-hop to hardcore-punk to pop-rock. With two lead vocalists contributing additional diversity to the band's unpretentiously eclectic sound, the album is never boring. If the lyrics to such songs as "Walkabout" and "Unsaid" were half so engaging as the melodies, DDT might amount to something more than an unusually canny purveyor of multi-hyphenated rock.

Atlanta's Billionaire has a simpler agenda. This quartet's second album, "Ascension," consciously evokes the grand, yearning style of the late-'60s Brit bands whose more bombastic moments were later forged into metallic archetypes. (In other words, they sound like a stateside version of the Verve.) Produced by Chris Kimsey, who began as an assistant producer for sessions by Led Zeppelin and the Rolling Stones, the album has enough swagger and swoon not to seem a mere simulation of its models. Such tunes and textures songs as " 'Til You're High" and "I Fell From Space" are suitably stratospheric. Still, when singer-guitarist Marc Tompkins announces that "I am the brightest star to ever fall from space," he's pushing his luck.

All appearing Sunday at the 9:30 club.

* To hear a free Soundbite from Megadeath, call Post-Haste at 202/334-9000 and press 8109. For a Sound Bite from DDT, press 8110. For a Sound Bite from Billionaire, press 8111. (Prince William residents, call 690-4110.)

CAPTION: Not just the faces of death, but of Megadeth! Jimmy DeGrasso, left, Dave Mustaine, David Ellefson, Marty Friedman.