record the lead vocal, Visconti devised a "multi-latch" system that would utilise the ambience of Hansa to full effect. Three Neumann microphones were used to capture the vocal: the first, a valve U47, was set up nine inches from Bowie; the second, a U87, was set up 20 feet away; and the third, another U87, about 50 feet away. The two farther mics were routed through a noise gate, a volume controlling device that would turn them on as Bowie's voice reached them. Visconti explained: "If he sang a little louder, the next microphone would open up with the gate, and that would make sort of this big splash of reverb, and then if he really sang loud, the back microphone would open up, and it would just open up this enormous sound." Bowie recorded three takes, the last of which mostly appears in the final song, and was completed in about two hours. Bowie and Visconti immediately recorded the backing vocals afterwards, harmonising in thirds and fifths below the lead vocal. The final mix was done at Mountain Studios in Montreux, Switzerland, a studio that would become one of Bowie's mainstays. An engineer at Mountain, David Richards, would also become one of his regulars. Composition Music Heroes was based on a G–D chord progression and contains five verses, some longer than others, and an outro. Primarily in D major, the verses move from D to G major, along with C major on "nothing will keep us together" and a foray into A minor and E minor on "beat them" and "forever". The song is mainly in the D mixolydian mode, wherein the A major dominant chord is replaced with A minor, likewise swapping from the parallel minor D minor back to the tonic D major. Richard Buskin of Sound on Sound described the song as a "highly experimental piece of art rock". Biographer David Buckley likens it to a Wall of Sound production, a forceful and noisy arrangement of guitars, percussion and synthesisers. Meanwhile, author James E. Perone finds the song a "great example of contemporary pop music", balancing early-1970s progressive rock on the sysnthesisers to the "avant-garde tone color manipulations" from Eno. According to Bowie, the track was "a combination of Brian's piano technique and [mine] which are both dastardly", turning into a reworking of the Velvet Underground's "I'm Waiting for the Man" (1967), a song long admired