onto other parts of it, through something Teo Macero calls a "recording loop". Macero later said of this production technique, "You hear the two parts and it's only two parts, but the two parts become four and they become eight parts. This was done over in the editing room and it just adds something to the music [...] I called [Davis] in and I said, 'Come in, I think we've got something you'll like. We'll try it on and if you like it you've got it.' He came in and flipped out. He said it was one of the greatest things he ever heard". DeJohnette's drums were also manipulated by Macero, who used an automatic switcher to have them rattle back and forth between the left and right speakers on the recording. In his book Running the Voodoo Down: The Electric Music of Miles Davis, Davis-biographer Phil Freeman describes this technique as "100 percent Macero" and writes of its significance to the track as a whole, stating: Composition Titled as an exhortation by Davis to McLaughlin, "Go Ahead John" features a basic, blues motif, centered around E and B♭, as well as modulations introduced by Davis into the D♭ scale. The recording begins with McLaughlin's funky wah-wah lines, backing Grossman's sharp, restrained playing, with Davis's first trumpet solo entering at four minutes with scattered ideas. In his book Milestones: The Music and Times of Miles Davis, Jack Chambers writes that the recording's first 11 minutes and its closing four-and-a-half minutes "resemble Willie Nelson [from Jack Johnson] as a head arrangement built on a riff, with the riff sustained this time by McLaughlin's steady wah-wah in the background. Approximately six minutes into it, McLaughlin's guitar solo succeeds Davis's first solo, as the band vamps. Music journalist Todd S. Jenkins writes of this passage in the recording, "Thanks to the then-new wonders of noise gate technology, Jack DeJohnette’s drums and cymbals flit back and forth rapidly from left to right in the mix. With each switch, the guitar’s volume blasts in and out, over and over again, during McLaughlin’s relentlessly acidic solo". Following the passage, an unrelated theme opens with two minutes of a slow blues segment by Davis that is spliced into the recording, accompanied solely by occasional notes from Holland; According to Jack Chambers, Davis's blues solo "becomes a duet with himself by overdubbing, and then builds into a quintet