Jack White explained to Guitar World
magazine (August 2007) about the super-low guitar sound on this song: "That might be the POG [Electro-Harmonix Polyphonic Octave Generator] and the HOG [Harmonic Octave Generator, also by Electro-Harmonix]. I don't remember exactly. We were trying to get low octaves that sounded real heavy without sounding garbled. We tried it with Blue Orchid on the last album. There were two tracks of POG on there, but with an eight-track tape machine, I couldn't get it to sound as heavy as I wanted. We had to lighten it up a bit; it was getting too distorted and blown-up sounding. On this album, we had a little more finesse. We had better equipment, so we could get that fourth octave down, or whatever it is, from the HOG."
Bertrand - Paris, France, for above 3