The dancing days of the '70s may be long gone, but a few disco dinosaurs still walk the earth. Two of the decade's biggest acts, the Bee Gees and Donna Summer, mined platinum out of the floor-shaking beat, and even with the passing of Studio 54 and the rise of MTV, both have proven themselves canny survivors.

The Bee Gees: 'E.S.P.'

As pop's foremost chameleons, the Bee Gees have a long career of discarding old musical colors in favor of newer, trendier ones. The Australian brothers spearheaded the second wave of British invaders in the late '60s, beginning as Beatles imitators, then borrowing brilliantly from black rhythms for their late '70s white-soul period.

Now it's the late '80s, the age of synthetic pop -- and they're back again, returning in the form of micro-Chipmunks. It seems Barry, Maurice and Robin Gibb used their six-year sabbatical following the relative flop of "Living Eyes" to listen to the radio and bone up on pop charts and computer manuals. "E.S.P" (Warner Bros. 25541), their 25th album, finds them fully armed with the latest sequencers and samplers. As a result, only their flair for finding a real melody and those eerie, sometimes irritating trebly voices distinguish them from the rest of today's untouched-by-human-hands pop.

Inside the vaguely U2-ish jacket (which features the aging Gibbs striking silly, moody poses on a craggy landscape) is an ornate, densely layered construction job -- the Trump Tower of pop. It was painstakingly produced by the Gibbs and Arif Mardin, and the pain is audible. They would have done well to take a cue from Scritti Politti, whose airbrushed, featherweight R&B improves on the Bee Gees' blueprint for blue-eyed soul.

The 10 tracks are tyrannized by a drum machine that pounds with relentless, monotonous, metallic zeal, even hammering down the beat for the ballads. Current-make keyboards and the Bee Gees' own helium warbles and sighs wash over this bottom-heavy foundation. But the vocals are encased in a distancing aura of echo -- they're so removed that they often sound more like a computer-imaging of a human voice.

Still, the Bros. Gibb can write pop hooks like few others, and that's what's kept them in business. The songs on "E.S.P." don't make any more sense than usual, and could have been written in any one of the Bee Gees' three decades. But if you can ignore the pistonlike mechano-stomp that almost ruins the first single, "You Win Again," you'll find its chorus unshakable after the first spin.

Most of the other tunes exert a similar magnetic force, such as "Angela," the kind of chiffon ballad that's a Bee Gees trademark; "This Is Your Life," a sort of career retrospective incorporating a clever collage of Bee Gees titles; and the vaguely Caribbean lilt of "The Longest Night." But the Bee Gees end a respectable LP by falling flat on their collective backsides with "Backtafunk," a laughably pale imitation of Cameo.

Face it: As long as there's pop music, there will be Bee Gees, remaking every new sound and style in their own image. Just be thankful they decided to sit it out during punk.

Donna Summer: 'All Systems Go'

Donna Summer, too, knows how to ride the changes: The singer has moved from Euro-disco to American pop charts, from movie sound tracks to Las Vegas shtick. More recently, she entered a born-again phase, alienating a large portion of her early constituency.

Now Summer is back with "All Systems Go" (Geffen GHS 24102), a commercially calculated piece of craft that shows she's still one of the great pop singers -- easy, assured, effortlessly muscular and musical, she seldom oversings.

But where Summer once led the pop pack, now she's following: From the jacket illustration, a blatant imitation of Janet Jackson's "Control" cover, to the standard-issue synth settings by producer Harold Faltermeyer, Summer is making conservative choices, venturing only where someone has been before.

Summer cowrote seven of the nine songs, and it's surprising that there's not a strong dance number among them. The tunes are shallow, undistinguished AOR stuff tricked out with electronic textures, and, like the Bee Gees, her voice is processed almost beyond recognition, coated with audio silicone and sheathed in metallic casings that obscure the character and warmth of her sound.

"Love Shock" apes Tina Turner's recent hits, and "Jeremy" is an insipid ballad in the style of Summer's successor, Madonna, with the strong-voiced Summer even incorporating the Material Girl's shaky warble. "Thinkin' 'Bout My Baby" is set to an appealing loping rhythm, but Summer sounds disconcertingly like Rickie Lee Jones. "Only the Fool Survives" was written by a committee of six -- and still fails to stand up as a lyric or melody. Summer duets here with the Starship's sexless Mickey Thomas -- why not with Grace Slick, who would at least provide a challenge?

Then there's "Bad Reputation," which sounds at first as if it might be a return to her finest hour, the naughty "Bad Girls" LP. But it's just the opposite, a voguish and insipid safe-sex song. Imagine Donna Summer, who began her career simulating orgasms at 135 beats per minute, delivering this warning: "Promises, promises, don't waste your time/ If his intentions don't feel right."

The album's only real sparkler is the first single, "Dinner With Gershwin," a clever love song that includes a roll call of role models, written by Brenda Russell and fetchingly produced by the pope of pop, the infallible Richard Perry.