His cause of death was not publicly revealed.
The producer and member of groups Tackhead and Little Axe passed on April 4 following an undisclosed illness.
Billboard pays tribute to the executives, songwriters, managers, producers, promoters, radio hosts and more who passed on this year.
He recorded for Disques Vogue and Columbia Records, appeared in films including Asphalte and The Devil's Brigade and voiced one of the Merry Men in Shrek.
The poet, singer and writer died of heart failure on Tuesday morning (April 2) in Detroit.
McMartin guided the career of Hoodoo Gurus for four decades and established the professional framework for the music management community.
The Grammy-winning musician performed frequently at La Scala opera house in Milan.
The Oxnard, Calif., native's manager, Jack Sills, announced the news on Instagram.
The rare student of Vladimir Horowitz, he made a dazzling Carnegie Hall debut at age 20 and performed major concertos from Chopin, Mozart, Rachmaninoff, Liszt and Prokofiev.
The British singer-songwriter was undergoing cancer treatments.