Thomas S. Steele, 69, formerly of Cherry Hill, a mastering engineer who helped create "Philadelphia Sound" recordings, died of complications from heart surgery March 6 at Naples Community Hospital in Naples, Fla.

Mr. Steele was cofounder of Frankford/Wayne Mastering. Before the advent of CDs, mastering labs transferred magnetic tapes from recording studios onto acetate discs.

"It was the final step between the recording studio and the pressing plant," said Joe Tarsia, a retired recording engineer who owned Sigma Sound Studios in Philadelphia. "Mastering was a tricky mechanical process and an art."

Even after CDs became popular in the 1980s, he said, mastering was important because sound could be "brightened" and other adjustments could be made.

Songwriter-producers Kenny Gamble and Leon Huff, who founded Philadelphia International Records, used Sigma Sound Studios and Frankford/Wayne Mastering to record their artists, including Harold Melvin and the Blue Notes.

Mr. Steele also mastered records by the Jackson 5, Stevie Wonder, and B.B. King. He received gold and platinum records for mastering "Celebration" by Kool & the Gang, "Move This" by Technotronic, "Me and Mrs. Jones" by Billy Paul, and "You'll Never Find Another Love Like Mine" by Lou Rawls, said his daughter, Tracy Steele-Mahoney.

Mr. Steele started Frankford/Wayne with a partner, Wayne Wilfong, in his parents' basement in Frankford. By the mid-1960s, Frankford/Wayne was sharing a Center City space with Sigma Sound Studio.

In the 1970s, Frankford/Wayne and Sigma opened New York City studios. Mr. Steele had operations in Philadelphia and New York until 1986 and then worked out of New York for another seven years. In 1993, he retired from Frankford/Wayne, which his daughter now operates.

For 10 years, Mr. Steele was owner, chief engineer, and manager of WMOO-FM in Derby, Vt. He sold the station in 2001. For the last several years, he wintered in Bonita, Fla., and summered in Vermont.

Mr. Steele graduated from Frankford High School and attended Temple University for two years.

He was always a tinkerer, his daughter said. As a teenager, he had a pirate radio studio in his parents' basement in Frankford that was closed down by the FCC, she said. He was also a DJ for radio stations in Philadelphia and Camden before establishing Frankford/Wayne.

In addition to his daughter, Mr. Steele is survived by his wife, Carrie Steele; a stepdaughter, Chelsea Ann Pulver; a brother; a grandson; and his former wife, Lynn Ballen.

No services are scheduled.

Donations may be made to Frontier Animal Society, 502 Strawberry Acre, Newport, Vt. 05855.

Contact staff writer Sally A. Downey at 215-854-2913 or sdowney@phillynews.com.