Question: The success of the remix of Unforgettable, by Natalie Cole and her father, Nat "King" Cole, has made me curious about this process. How is this duet created? Is this the first time such an electronically manufactured session has produced a hit? Are there any other mother-daughter, father-son, mother-son, father-daughter combos? _ Mary Shively, Ann Arbor, Mich. Answer: Manufactured duet recordings have been discussed in this column before, most recently when we had a question about Save the Last Dance for Me, by Jerry Lee Lewis. On this one, there was an Elvis-sounding vocalist, Jimmy Ellis, singing with the old Lewis master to give the impression that Lewis recorded the song with Elvis Presley. With Unforgettable, Natalie simply sang her lines to the song, while Nat's voice track on those same lines was eliminated. To create a true duet effect, Nat's voice would be left in but attenuated slightly so Natalie could sing along. The effect would be as if they were actually in the recording studio together, though Natalie was 1 year old when Nat recorded Unforgettable. One of the finest examples of electronic duet gimmickry is There's a Tear in My Beer, the recent pairing of Hank Williams Jr. with his dad, Hank Williams Sr. Another is the magical teaming of two deceased stars who never recorded together: Jim Reeves and Patsy Cline. Two instances of father-son duets actually recorded together in the studio are Bobby Bare and a then 5-year-old Bobby Bare Jr. (Daddy What If, 1973), and Roy Rogers with son Dusty Rogers. Roy (the cowboy star and not the blues singer of the same name) and Dusty recorded together on a new tribute album to Roy, set for release this month. Several other fathers and sons have recorded separately: Dean Martin and the late Dino Martin, Frank Sinatra and Frank Sinatra Jr., Marty Robbins and Ronnie Robbins, and Jerry Lewis and Gary Lewis. The best-known mother-daughter team is surely the Judds. Good father-daughter affiliations would be Johnny and Rosanne Cash and Frank Sinatra and Nancy Sinatra. Of course, don't forget the Zappa clan. Question: In late 1968, a Seattle Top 40 station played a song by Johnny Tillotson that had a three- or four-word title. I have searched everywhere, including the public library's file of radio stations' surveys, without success. I am hoping you can solve this puzzle for me _ I doubt anyone else can. _ Robert Sherrill, Tacoma, Wash. Answer: Though Johnny Tillotson had no nationally charted recordings after 1965, he did continue to record. His releases for the second half of 1968 were: Why So Lonely/I Haven't Begun to Love You Yet (MGM 13924) and Letter to Emily/Your Memory Comes Along (MGM 13977). Both have three word titles _ perhaps one is the answer to your mystery. Question: I have what I think is a very early record by Tony Orlando on the Milo label. It's a doo-wop type song titled Ding Dong. When did it come out and what could it be worth? _ Patrick Corwell, Easton, Pa. Answer: The Tony Orlando who recorded for Milo is not the singer who had hits in the '60s as a solo act, then joined Dawn in the '70s as "Tony Orlando and Dawn." Now the good news: Ding Dong, a 1959 release, is worth far more than any singles by the well-known Tony Orlando. Its current price range is from $50 to $75. 1991 World Features Syndicate