Zoo Station - Composition

Composition

As the first track on an album that was a major reinvention for the band, "Zoo Station" was an introduction to U2's new sound. The song features layers of distorted guitar and vocals, and industrial-influenced percussion. Irish rock journalist Bill Graham cites David Bowie's album, Low, as a major influence on "Zoo Station", which he called a "new brand of glam rock" with "Spartan rhythms and sudden flurries of melody".

"The opening of 'Zoo Station' makes a powerful statement: in its deliberate use of 'industrial' sounds that remind us not at all of conventional instruments, in the foregrounding of technology at the beginning of the song—indeed, in making this the opening statement of the album—there can be no mistake that U2 has embraced sound resources new to them. But the fact that it is a deliberately hesitant gesture puts it clearly in the realm of satire. Perhaps it satirizes the technology itself, or U2's new embracing of technology."

The song is played at a tempo of 129 beats per minute in a 4/4 time signature, but only one element of the song's introduction, a marimba-like texture, is played in common time. This sound, which has been compared to that of a clock ticking, was achieved by picking the guitar's D string behind the bridge and the stopbar. On the second half of the third beat, the song's signature guitar riff, a distorted descending glissando, enters. The glissando descends past the octave it begins in by a major second before returning to it. After the second time it is played, an "explosion" of percussion is heard, playing on beat four of every second measure on two occasions. This percussion sound, played by Flood, enters early the third time, being played on beat two. The drums then enter, before stopping and starting again. Much like the song's guitar sounds, the drums' timbre is noticeably different from previous U2 songs as it exhibits a "cold, processed sound, something like beating on a tin can". Amidst layers of various guitar sounds, the bass enters, the part played in the introduction and verses consisting of repeating G and A notes, mimicking the ascending portion of the guitar riff after the glissando overshoots the octave. After the bass begins, the song's regular groove is established. At 0:45, the chord progression changes. Fifteen seconds later, the song returns to the previous chord progression and the introduction ends.

Guitarist The Edge explained that some of the sounds in the introduction that resemble keyboards were actually created by him on guitar. Of the song's introduction, bassist Adam Clayton says, "When people put on the record, we wanted their first reaction to be either 'this record is broken' or 'this can't be the new U2 record, there's been a mistake.' So there is quite a dramatic extended intro where you just don't know what you are listening to." Author Albin Zak, in his book The Poetics of Rock, says of the introduction, "Before any words are sung, the sounds alone alert the listener that the band has moved into new expressive territory."

After the introduction, the song follows a conventional verse-chorus form. The first verse begins one minute into the song, with Bono announcing, "I'm ready, I'm ready for the laughing gas". During the verses, he sings primarily in a medium-to-low range and his vocals are treated with heavy processing, which takes out the bottom of the sound and "emasculate" his voice. The processing also introduces a wavering quality to his vocals. The guitar glissando continues to be played during the verses. The first chorus begins at 1:44, and the music mirrors the change in chord progression from the introduction's last 15 seconds. During the chorus, the bassline becomes more dynamic, playing descending quarter notes of G–F♯–D–C–D–C–A–G–A, before resuming the previous G and A pattern. Bono's vocals also become more dynamic in the chorus, featuring layers of both "open-throated" singing and monotone lyric recitation, as well as both processed and unprocessed vocals.

Along with introducing the band's new sound, the song opens the album as a statement of intent. Lyrically, new anticipations and appetites are suggested ("I'm ready for what's next"), as is a willingness to throw caution to the wind and take risks ("I'm ready to let go of the steering wheel"). Some of the lyrics, particularly those in the bridge before the final chorus, use the eponymous subway station as a metaphor for time: "Time is a train / Makes the future the past / Leaves you standing in the station / Your face pressed up against the glass". Bono cites the enjoyment of his first child born in 1989 as a major influence on Achtung Baby, as was his wife's second pregnancy during the album's 1991 recording. Bono says babies influenced the lines from the first verse, "I'm ready to say I'm glad to be alive / I'm ready, I'm ready for the push".