RICKY NELSON calls it a "new type of sound" but it's still basically a Country-Western beat with an occasional flash of Cajun allegro or of Beatles balladry.

It's the kind of sound that has brought Nelson back into the fold of top hit singers in the United States. But it still includes some of the numbers that made him a teen-age star, such as "Poor Little Fool" and "My Bucket's Got a Hole in it!"

Nelson has been spreading this sound around military clubs for the past three weeks during a European tour that winds up Sunday. His wife, Kris, the daughter of ex-football star and Air Force pilot Tom Harmon, is accompanying him.

"It's my first time over here," Nelson said before a club date Tuesday. "But we haven't had any time off to see the country."

Sipping a pre-show soft drink, his face still boyish looking under the mop of hair that has taken the place of the musician's pompadour of the '50s, Nelson barely looked like a 29-year-old father of a girl, 6, and two-year-old twin boys.

THE SON of the radio and television personalities Ozzie and Harriet, Nelson is one celebrity offspring who has escaped from his family's limelight. It helped that Ricky and his brother David were a part of the show's cast.

"I've been working all my life and singing since I was 16. Music is a part of my existence," he explained.

"What I've developed is a new type of sound, a combination of country, rock and folk." Whether it's new or not, it's successful. Nelson's latest song, "Born to be Free," which he wrote, is doing well on the popularity charts.

Nelson concentrates on the singles market and is under a 20-year record-company contract calling for him to make four single recordings a year.

The singer thinks pop has broadened the interest in music in the United States.

"Musicianship has gotten better," he noted. "There are lots more kids playing musical instruments than ever before.

"It's not the same kind of playing there was in the past. The kids are playing guitars now, not pianos. But music isn't so removed the way it was before, when you had to play scales all day long."

AFTER A week's rest at his home in Laguna Beach, Calif., Nelson will do a concert in Nashville with Johnny Cash. He still looks like one of the guitar-happy kids he talks about.

On stage, he can talk about wearing brown shoes and white sweat socks with his high-school graduation tuxedo and it sounds as if it happened yesterday (he never went to college or served in the armed forces).

When he smiles or tells jokes, his face assumes at once an overwhelmingly eager-to-please look.

To date, there is no doubt whatsoever that he has succeeded.

Migrated