It turns out that the Billie Jean chord stab sound is more complex than we thought: it needed 3 Yamaha CS-80 synth layers and vocal ‘oohs’ from Michael Jackson

Synth programmer Anthony Marinelli has revealed some fascinating stuff about the making of Michael Jackson’s Thriller album this year, and his latest revelation is that the iconic chord stabs that play such a crucial role in Billie Jean are actually made up of four separate layers - three Yamaha CS-80 synth patches and some vocal ‘oohs’ from Jackson himself.

On the original recording, the CS-80 was used to create string, brass and vocal-like tones, and, in his latest video, Marinelli shows you how they were programmed and how they blend together to form what he calls the ‘chord stack’. He also has a go at recreating the strings element of the sound on a Prophet-5 to see how close he can get to matching the CS-80. Why? Because he can.

What of those vocal ‘oohs’ from MJ, though? Marinelli says that his two-part harmony includes two of the notes featured in the chords that are played. It’s designed to complement the CS-80 ‘oohs’, and provides a dash of “secret sauce” to the overall sound.

In a previous video, released earlier this year, Marinelli revealed that the bass sound from Billie Jean also uses four instruments: three synths and an electric bass guitar. Check that one out below.