One need only consider Frank Sinatra, Elvis Presley or Diana Ross to realize that most pop singers deteriorate vocally as their careers progress. Yet Smokey Robinson has not only held his own, he has improved dramatically as a singer over a 23-year recording career. On the four albums since his 1979 comeback, his voice has been richer in tone, more versatile in dynamics, more inventive with embellishments and more expressive emotionally than it ever was in his glory days with the Miracles during the '60s. Robinson isn't writing the quantity or quality of songs he did in those days, but his new vocal abilities have made his comeback a success. While the Temptations once did definitive versions of Robinson's tunes, no one could improve the songwriter's performances of his own songs.

Robinson's new album, "Yes It's You Lady" (Tamla), contains a revealing remake of his "I'll Try Something New." On the original 1962 single with the Miracles, Robinson sang in a pretty but frail high tenor that lacked body or nuance. On the new 1982 version, the same notes have a full-bodied resonance that shimmers with warmth and confidence. The original was a simple adolescent promise to do anything for his sweetheart. The remake--with its hints of regret and desperation--sounds more like an effort to save a faltering marriage.

Like last year's "Being With You," Robinson's new album was made with the production team of George Tobin and Mike Piccirillo. These L.A. pop pros keep everything smooth, never suffocating. As a result there isn't a convincing dance track on either album, but the love ballads are suffused with so much romance that they rank with Robinson's best work. Piccirillo and lyricist Gary Goetzman wrote three of the album's nine tracks. "Tell Me Tomorrow" is 6 1/2 minutes of progressive soul in the style of Stevie Wonder or Marvin Gaye with funky, slapped bass and jazzy solos. By contrast, "Old-Fashioned Love" is a pretty, old-fashioned love ballad. Robinson shines in both settings.

Robinson himself wrote four songs, including the oldie. "International Baby" is an embarrassment built around a badly contrived literary conceit. The other three, though, are the album's highlights. "Yes It's You Lady," the title track, is a silly love song with a strong melody in the chorus. Buoyed by Joel Peskin's warm, grainy saxophone, Robinson's equally reedy voice breezes through the song like a sloop across a harbor.

The album's best song, though, is Robinson's "Are You Still Here," a stunning ballad that ranks with "Being With You." The lyrics, full of nifty internal rhymes, effectively describe a couple who have decided to end their relationship but can't quite let go. Robinson sings the question, "Are you still here?" a cappella to start each chorus. He pauses between each syllable and then lets it go with a ringing bell tone that echoes with all the fear and hope of an affair that won't end. Then he glides effortlessly into the swooning romance of the main melody.

Al Green hasn't lost anything as a singer either. In 1979, Green ostensibly gave up the sexy soul singing that had made him a superstar to devote himself full-time to gospel music. Yet his 1980 album of traditional hymns, "The Lord Will Make a Way," for the gospel label Myrrh, featured his same old sexy sound behind the sacred lyrics. Green's new all-gospel album "Higher Plane" (Myrrh) lacks the dizzying excitement of its predecessor, but proves Green is still one of his generation's great singers.

The crack Memphis horn team that fired Green's soul hits and last gospel album is gone. In the horns' absence Green resorts to slower, longer arrangements. The driving momentum is sacrificed, but Green gets more room to stretch out and play in his vocals. The whole second half of "The Spirit Might Come--On and On," consists of the title chanted over and over. Green leaves the chanting to his backing choir and improvises brilliantly around them. He raps in counterpoint; he lets loose with yelps; he chuckles on the beat; he squeals giddily; he employs every trick of the great vocalist he is.

He does the same in a very slow and long version of Curtis Mayfield's "People Get Ready." Duetting with Marjie Joseph, he sings slippery, sensual rings around her traditional gospel approach. As on several cuts, Larry Lee's guitar solos add a cutting edge to the soaring harmonies. Unfortunately, Green submerges himself into the choir on the old war horses, "Amazing Grace" and "Battle Hymn of the Republic." On "By My Side," he bounces in sinful syncopation off the up-tempo rhythm. "His name is Jesus," the show-stopper of his recent Constitution Hall concert, also highlights the album. Green holds the first syllable of "Jesus" in a dazzling falsetto until he squeezes every drop of possible music from it. Green pushes the song's rhythm relentlessly to a ferocious climax.