Singers who trade in sexual ambivalence have always found cabaret life agreeable and Peter Allen is no different. What sets Allen apart from the pack, though, is an extraordinary level of energy and a cult following large enough to support his appearances at Radio City Music Hall or Wolf Trap, where he appeared last night.

The Rockettes weren't there to kick up their heels, but Allen sure did; at least on those rare occasions when he wasn't hip-shaking across the stage to a Latin beat or posing suggestively atop his piano. And everything else that goes into making Allen's performances fashionably hip, shamelessly so, surfaced as well. His between-songs patter was often wickedly funny, brimming with the latest dirt on Liz and Lady Di, as well as a story about Allen's recent encounter with Frank and Nancy Sinatra ("She was still in those boots").

Ironically the least successful part of the show was devoted to Allen's rather routine versions of the big hit songs "that turned a simple songwriter into a simple songwriter with a swell beach house." Far more impressive were lesser-known tunes like "Quiet, Please," an affectionate tribute to Judy Garland, and a couple of standards that sounded as if they were arranged for an old-fashioned Copa floor show.

"We can't all be Lena the first time out," said Allen at one point. Maybe not, but he and an orchestra that stretched from wing to wing gave it their all just the same. --Mike Joyce