Noun
machine head (plural machine heads)
(music) A geared apparatus for tuning stringed instruments by adjusting the tension of the strings.
I don't do Machine Head songs. Source: Internet
Slapshock was also the first-ever Filipino and Asian artist to have participated in the Dubai Desert Rock Festival in 2008, where they shared the stage with international heavy rock talents such as Velvet Revolver, As I Lay Dying, Machine Head and Muse. Source: Internet