Mike Tarsia, an audio engineer who mixed for legendary musicians Patti LaBelle and Teddy Pendergrass, worked on the soundtracks of films such as Beverly Hills Cop and Coming to America, and was the son of Sigma Sound Studios founder Joe Tarsia, died Saturday, Dec. 4, at age 64.

A family friend confirmed Mr. Tarsia’s death. A relative reached by phone Saturday declined to speak further. Several people who knew Mr. Tarsia said his wife shared the news of his death in a brief Facebook post Saturday. No cause was given.

“I am, along with the rest of the ‘Sigma Sound community,’ in a state of shock,” Arthur Stoppe, a former engineer at Sigma, said by email.

Mr. Tarsia was 4 years old when he started watching his dad work in the studio, and, as he got older, assisted on sessions for Thom Bell, Kenny Gamble, and Leon Huff, according to the bio on the website of Mr. Tarsia’s own studio, Mike Tarsia Recording. Those “Mighty Three” producers and songwriters developed the Sound of Philadelphia for which Sigma became famous.

It was at Sigma that Mr. Tarsia also had an early encounter with David Bowie. In 1974 the British musician recorded songs for his album Young Americans at the studio on North 12th Street. Behind Bowie’s colorful persona, “he dressed down very conservatively, he was very soft-spoken, and he was so intelligent,” Mr. Tarsia recalled in a 2016 interview with NBC10.

And no matter how famous the name, Mr. Tarsia recounted in the same interview, whenever someone walked into Sigma “there was an equality going on — we’re all working together for the same goal.”

Mr. Tarsia took over Sigma from his father in 1990 and the business was sold in 2003. Then, in 2006, Mr. Tarsia founded his eponymous recording business, according to his LinkedIn profile.

“I had never seen somebody who was so intuitive about the sound process,” said drummer Rob Smith, who first met Mr. Tarsia in 2001. “He just always could zero in on the problem instantaneously.”

Mr. Tarsia ran his studio out of his home in South Philadelphia, while drawing international clients. “People from all over the world were sending him tracks to mix them and master them,” Smith said.

On Friday, Smith, who now lives in New Orleans, said he’d been joking back and forth with his friend on Facebook. “It’s a huge loss for Philadelphia,” he said. “Huge.”

Randall Grass, general manager of Shanachie Entertainment, had interviewed Mr. Tarsia two or three weeks ago for a book on the history of Philadelphia music.

“He was very passionate about the way Philadelphia does not celebrate its music history,” Grass said.

Last year, Mr. Tarsia advocated for the preservation of the Sigma Sound building, which had been purchased by developers, as a site where clients and musicians “broke racial and cultural bias to create a ‘rainbow family’ of music,” he wrote in an August 2020 Facebook post.

Three months later, the building was designated a historic place by the Philadelphia Historical Commission — and Mr. Tarsia, in another social media post, thanked everyone who helped the effort on behalf of his “pop.”

Grass and others also described Mr. Tarsia as someone always willing to speak his mind.

“He approached everything full on,” Grass said. “He was funny, he was smart, he would say outrageous things.”

Jazz musician Jawanza Kobie worked on two albums with Mr. Tarsia, the latest released earlier this year.

Composition of music is one thing, and the performance of it is another, and “then it becomes the overall sound,” Kobie said. “Mike was my secret weapon.”

The two kept a friendship outside the work and shared a similar sense of humor, Kobie said.

“Mike was wild. He was a character,” Kobie said. At the same time, “you couldn’t find a more caring, compassionate person.”

“It was a refreshing thing to be around someone like that.”

Mr. Tarsia is survived by his wife, daughter, sister, and parents Joe and Cecilia.