You are here

Robbie Adams: Recording U2's Achtung Baby & Zooropa

Interview | Engineer By Paul Tingen
Published March 1994

Young Irish engineer Robbie Adams played an important part in the recording of U2's popular and critically‑acclaimed albums Achtung Baby and Zooropa. Here he gives Paul Tingen a fascinating insight into the exciting and unorthodox recording methods they used.

U2 have the rare distinction of being a major band that have consistently reaped both commercial success and critical acclaim. Most artists that have achieved mass popularity are dropped by large sections of the British music press like a hot potato and subsequently need elephant skins to deal with the abuse heaped on their work. Whatever the ins and outs of the partisan and prejudiced nature of much of the British music press, which often appears to focus on peripherals like age and trendiness rather than music, the fact that U2 haven't been reviled in accordance with their status must have something to do with their stomach for musical adventures.

The band have never been satisfied to simply rest on their laurels and turn out the obligatory 5‑yearly disc with more of the same, only less inspired, music — unlike many other 'stars'. Ever since they burst on the international music scene in 1980 with the fresh New Wave‑inspired guitar‑rock of Boy, they've changed tack every time they threatened to become repetitive. The first great change of direction was with The Unforgettable Fire (1984). Out went the bucketfuls of reverb and monochrome colours of Boy, October (1981) and War (1983), to be replaced by a more intimate and atmospheric sound. Their most successful and classic album to date, The Joshua Tree (1987), continued the new trend, with added influences of American roots music. Then the band threatened to stagnate creatively. Rattle & Hum (1989), part live album, part covers, part original material, was an exploration and re‑evaluation of their American influences and musical heroes, such as Elvis and BB King. But the looming deadlock was quickly and rather dramatically avoided by another landmark, the bizarrely‑named Achtung Baby (1991), a dark, disturbing and gloomy piece of work, all distorted guitars and gothic‑sounding keyboards. The almost religious zeal of their previous lyrics had given way to a mixture of the doubtful, the cynical and the ecstatic. U2 went on the road with their mega Zooropa‑tour, featuring Trabant cars and video and other assorted imagery on stage, much of it exemplifying their confusion in a world of information overkill. Punters and critics were even more surprised with the next album, which appeared as if from nowhere. Like the tour dealing with the confusing influence of the mass media, Zooropa was nevertheless much more optimistic in feel than Achtung Baby, but with an experimental, dead‑pan slant.


Crucial to all the aforementioned major changes in U2's music were Brian Eno and Daniel Lanois. It was especially Eno who helped U2 to find a more understated, multi‑coloured expression on The Unforgettable Fire. Lanois is generally credited with bringing the fluid, rootsy sound to The Joshua Tree (they co‑produced both albums together). Lanois was also the main producer on Achtung Baby, probably the biggest change of direction in U2's career so far. The Canadian guitarist, who also produced Peter Gabriel's So and Us, plus his own two solo albums, commented when I spoke to him last year: "When I started work on Achtung Baby, U2 were interested in creating a more hard‑hitting, live‑sounding record. I myself had also grown rather tired of polishing details on records and pursuing the kind of perfection that has become commonplace in much rock music today. So what I did was push the performance aspect very hard, often to the point of recklessness. I think that musical recklessness goes a long way on records. You don't hear enough of it." Lanois, busy touring his own solo album during 1993, wasn't involved in Zooropa, which was instead produced by Eno, engineer Flood and The Edge, but his ghost nevertheless roamed the project, because his method of de‑constructing the conventions of the recording process were by now thoroughly integrated into the band's working methods. Lanois has become known for recording in houses, mansions or castles, and rolling in rented equipment to further the elusive feel and atmosphere factor. At the same time he likes to record in the impromptu 'control room', furthering communication and band confidence. This can obviously lead to problems with acoustics and seperation, but for Lanois a good performance will always take precedence over these traditional studio objectives. As he summarised it: "a good performance equals a good mix." He introduced U2 to this philosphy on The Unforgettable Fire, which was recorded in Slane Castle near Dublin. Backing tracks were always recorded live by the whole band, and tape‑recorders were kept running virtually all the time to capture spirited moments, whilst band and producers were couched in the inspiring and characterful surroundings of the ancient castle. Achtung Baby was made using similar premises, though for some reason, maybe because of Achtung Baby's German connections, many people are under the impression that most of the album was recorded in Hansa Ton Studios in Berlin. The truth is that the Hansa sessions lasted barely two months. The band subsequently spent almost half a year in a rented house by the sea near Dublin, using equipment rented from Audio Engineering, Ireland's largest pro‑audio hire company, before moving on to the legendary Windmill Lane studios in Dublin for the final mixes. Similarily, Zooropa was also largely recorded in improvised surroundings. These unusual recording surroundings must have awoken the muses, because the stories of the recording sessions for Achtung Baby and Zooropa recount chaotic and almost manic outpourings of creativity. They feature such unusual tales as: the band simultaneously using three rooms to record and mix and the various bandmembers overdubbing in the different studios with people running around with tapes from room to room; last minute overdubs during or even after the final mix; nightly flights home straight after European gigs to complete Zooropa; the filling of 180 2‑hour DAT tapes with a procedure called 'fatting', complete disregard for standard recording objectives such as separation and low noise levels, and last but not least the interesting dichotomy between the intense 11 months that it took to complete Achtung Baby, endlessly sculpting the songs into perfect shape, and the attitude of 'recklessness' and 'performance first' encouraged by Lanois.

They continuously experiment and try different ways of playing and arranging the songs, until the very last moment. The guitar overdub on 'Mysterious Ways', for example, went down after the mix was finished.

Excitement Level

Narrator of these stories is the young Irish engineer Robbie Adams, who's one of the people best placed to talk about the projects, since he was an engineer on both. Adams originally trained as an engineer in various small Dublin studios, and completed his apprenticeship working as an assistant engineer at Ringsend Road Studios in the late '80s — at the time one of Ireland's major studio complexes. Here he worked with The Commitments, The Waterboys and Hothouse Flowers and "anything that came through Ireland." Although Adams is a freelance engineer, the mainstay of his work during the last four years has been with U2, who first hired him as an assistant engineer to Flood on Achtung Baby. Adams, a quiet, soft‑spoken man, who spoke over a pint of Guinness in one of Dublin's stylish and very European coffee‑shops‑cum‑bars, remembered: "Initially, from February till the end of May 1991 there was a clear demarcation line between me and Flood, who was chief engineer. But when he had to go away for a month to a previously arranged session, there was so much work to do that instead of taking a month off, as was the original plan, Danny [Lanois] asked me to take over. We got another assistant in, Shannon Strong, and when Flood came back we suddenly had three engineers. It was then decided to work in two studios at the same time, one being Elsinore, a house in the village of Dalkey, close to Dublin, the other Edge's home studio."

Elsinore was a relatively modern house with a large but narrow front room, chosen by the band because of its location 20 yards from the sea, and nicknamed Dog Town by them because of its "tackiness." Recording in two studios at the same time worked really well, recalled Adams, because "it increased the level of activity and enthusiasm. There was always something different to listen to, always something exciting happening. Steve Lilleywhite, myself and others would go to Edge's house in the morning and come back at dinner time, and the rest would be looking forward to hearing what we'd done. We'd compare and exchange opinions. It was progress, like a gift, and kept the excitement level up. It avoided that bogged down feeling that you can get from just mulling over the same thing all the time." The reason why the Achtung Baby sessions lasted an epic 11 months, despite the two studio/three engineer/three producer (Lanois with help from Eno and Lillywhite) setup and Lanois' professed preference for working quickly was, explained Adams, that U2 "write their music in the studio. They continuously experiment and try different ways of playing and arranging the songs, until the very last moment. The guitar overdub on 'Mysterious Ways', for example, went down after the mix was finished. That kind of thing is very common with them. And when you do an instrumental or vocal overdub the whole perspective might change and you might want to change the bass part, or the drums, or both. Things mould themselves as they go along. You wouldn't recognise some of the original demos of their songs. That's the kind of freedom that you have when you work a long time on something — you can keep changing until the deadline arrives."

Spill? What About It?

It turns out that Lanois' country‑house recording method has the added benefit of being very cost‑effective. Adams elaborated: "You can rent in the equipment as you go along, starting with basic control equipment, like a tape recorder, and a desk and a few reverbs to do monitor mixes. When you're a band you also save on accommodation, because people can sleep in the house. In this case, because they were only a few miles away from their living quarters, U2 went home every night, but Danny and Flood actually slept in the house. Added benefits are that you can create your own atmosphere, choose your own furniture and lighting and generally create a relaxed, homely feeling that's very conducive to work. The whole thing takes away the time pressure that you feel when working in a studio with the clock ticking away."

Sessions for Achtung Baby started in late 1990 in Berlin, where the band worked for six to eight weeks, after which they took a three‑month break, resuming work at Elsinore in February 1991. The initial basic control setup consisted of Audio Engineering's Soundcraft 6000 44‑input desk, Otari MTR100 analogue 24‑track with Dolby SR, and ATC100A, Westlake BBSM12 and NS10 monitors. After a while they switched to Audio Engineering's freshly reconditioned, 1970s Neve EMI desk, a unique, vintage, 36‑channel device. During that time the Soundcraft was mainly used as a studio monitoring desk.

Despite Lanois' preference for recording artists in the control room, the recording room was diagonally beneath the control room in a converted garage, the biggest room in the house. The band would communicate with Lanois, Adams and Flood via TV monitors and foldback mic. In a room adjacent to the garage, Joe O'Herlihy, normally U2's live sound mixer, was set up with a Ramsa PA desk, controlling the band's on‑stage wedges, now being used for monitoring. Overdubs did take place in the control room upstairs, where two enormous EGV monitor speakers were used at very loud playback volume. Apparently the band hate playing or singing to headphones. The obvious question is how Adams and Co dealt with spill:

Mixing, like music, is a very personal thing. It's the people that are important, and the machines and the quality of them is very secondary.

"Spill, what about it? They didn't worry about it and neither did I." In September 1993 the whole party moved to Windmill Lane for the mixes, where Audio Engineering set up the Neve in the live room, opposite the SSL in the control room. An odd situation arose, with Lanois and Flood behind the SSL and Lillywhite and Adams behind the Neve. The band members would be running around between the two rooms with tapes, and for the obligatory last‑minute overdub. Vocal overdubs were done in the control room, and Edge had a couple of guitar amps in an adjacent live room. Adams: "It was very funny actually. We would be looking at each other through the glass and there was this kind of competition, like who would get their songs mixed first and all that kind of stuff. It was very exciting for the band because they could go from one room to the other and work on different songs, and if we felt we got bogged down we could go to the other room and watch them work, to clear our our heads."

Team Effort

In the end Adams engineered and mixed three songs on Achtung Baby: 'Who's Gonna Ride Your Wild Horses', 'Tryin' To Throw Your Arms Around The World', and 'Even Better Than The Real Thing'. On Zooropa, however, he was involved as a fully‑fledged engineer from the beginning and mixed the tracks 'Numb', 'Some Days Are Better Than Others', 'Dirty Day' and 'The Wanderer', on which the legendary American country singer Johnny Cash was guest vocalist.

The story of Zooropa is slightly different, because it was originally only intended to be a 4‑track EP, not the full album it became. Starting with snippets of ideas developed during soundchecks, the aim was to work these ideas into songs and rehearse and record them at the same time, in The Factory rehearsal studio in Dublin. Once more, Audio Engineering installed the trusty Soundcraft 6000 console with Otari MTR100, plus four Neve record modules (to record vocals, kick and snare drum) and outboard gear like Urei 1176, dbx 120X‑DS, two Summit and two LA compressors, Focusrite 115HD equaliser, Yamaha SPX1000, Lexicon PCM70 and AMS RMX16 reverbs and NS10 and EGV monitors.

After the Achtung Baby recordings, Adams had been invited by the band to come on the Zooropa tour. He was involved with mixing live sound and a worldwide live TV broadcast in November 1992, and recorded many soundchecks on a 16‑track. Adams was given the job of sifting through these recordings and making loops of interesting parts: "This was during January 1993. U2 don't use loops taken from other people's records, so instead I made loops of Larry drumming. That worked quite well and several of the loops ended up on the record. In February, after several weeks of compiling loops the band came in and would ask me things like: 'have you got anything around 110bpm?' I'd play them what I had and they picked what they liked most. As the songs materialised, I changed the loops, putting in things that helped them on their way, like bringing structure into a repetitive part, so that there would be a verse loop or a chorus loop, with little fills here and there."

The equipment Adams used for looping was an Akai S1100 with a Macintosh running Vision software. This equipment was also part of their tried and tested live gear during the Zooropa tour. It was mainly Bono and The Edge who occupied themselves with the initial stages of demoing chords and melodies and song structures, which, asserted Adams, "was a good way of doing things, because you don't need a whole band around to try and come up with these things. A structure is either good or bad. But the whole band would be around for opinions and Larrry would sometimes come in to play over the loop or create another part." He paused for a moment and stressed: "Recording with U2 is very much a team effort — everyone's opinion is asked. These are not guys that will just get produced by a producer; they have their own ideas, but at the same time always asked for my, and other people's, feedback, because they know that everybody has a valuable opinion."


After the looping and demoing stage, Flood came in to assist Adams with the rehearsing and recording stage. The two‑studio situation was revived once more, with Flood working with an SSL in the new Windmill Lane studios (now merged with Ringsend Road), whilst Adams continued with the Soundtracs in The Factory. The loops were put to tape whilst the band were trying out various arrangements and parts for the song demos. An interesting recording method, employed both on the Achtung Baby and Zooropa sessions, was what they graphically called 'fatting'. Adams explains how to get 48+ tracks out of a simple analogue 24‑track, a DAT machine and a synchronizer. "There's one golden rule with these guys and that's 'never erase anything'. You simply record everything and put it in storage somewhere. Obviously the problem with 24 tracks is that you're going to run out of tracks if you're doing 10 vocal takes or something. What we do instead is record overdubs, which we're not sure whether we're going to use, to a Fostex timecode D20 DAT machine, that's linked to the Otari with an Adam Smith Zeta 3 synchroniser. The Fostex functions as an infinite 24‑track. Later we pick and choose the right takes and fly them back in onto the multitrack. I went through 180 2‑hour DATs for Zooropa in this way, which meant that I had to make very careful notes. During the initial demoing sessions, which lasted six weeks in total, I was the only engineer there and it was murder trying to keep track of everything."

Unlike Achtung Baby, where the band played in a separate room, at The Factory U2, desk and engineer were all in one big room, which had its consequences. Adams: "At Elsinore we'd placed Edge's guitar amps and Adam's bass amp in separate rooms, so that we got a degree of seperation. But in The Factory there was too much spill so we had to screen things off with flightcases and made little booths out of pieces of wood. Because of the way they work, recording many overdubs, you still end up with a lot of separation on tape. The main problem with spill usually came from vocal monitoring, because Bono often wouldn't have the lyrics ready yet, so you knew that he'd have to overdub that.

Spill, what about it? They didn't worry about it and neither did I.

"Once the band felt that they had a finished arrangement for a backing track, Bono would ease back on the vocals and just give cues, maybe playing guitar just to get a vibe going. A backing track for Achtung Baby or Zooropa generally consisted of four tracks of drums, a guitar and a bass track, and some guide vocals; there might be a loop going, plus a click track fed back to Larry during recording — he was the only one wearing headphones. Danny might be playing some percussion or guitar or doing some backing vocals, or Brian might have played some keyboards with them, all to get the energy going. They like to do that kind of thing especially in the first stages, when things haven't got a definite shape yet and enthusiasm and confidence are very important."

Cheerleader Mixing

This spontaneous attitude also permeated the mixing stage — automation, for example, was considered a bit of a non‑starter. Just as with Achtung Baby, everybody moved to Windmill Lane for the final mix, this time taking their simultaneous working methods to even greater extremes by using three rooms at the same time! Adams explained: "We had a lot to do because we were running out of time — we were suddenly working on an album instead of an EP. The last month was extremely hectic, because the band were gigging all over Europe and would be flying back from Paris or Berlin at night straight after the gig to be able to finish the album off in time.

"The reason for the time pressure was largely an issue of continuity. The whole project was on a creative roll and you don't want to stop that and come back to it six months later when you're likely to be in a completely different frame of mind. We were working day and night as well. Using three rooms meant that there was never anybody sitting around waiting or doing nothing. We used the SSL room downstairs in Windmill Lane for mixing, the live room upstairs with an Amek 2520 for last minute overdubs, and the other room was an editing room, with a Yamaha DMR8. We'd compile vocals on the DMR and then fly them back onto the 24‑track. We also used a Mac with Sound Tools to edit songs and final mixes. The latter were loaded into Sound Tools from DAT mixes. Once we'd made our decision on the Sound Tools we'd repeat the edits on the half‑inch mixes with a razor blade, so the only original, unedited mixes remaining were on DAT."

Daniel Lanois: "What I did was push the performance aspect very hard, often to the point of recklessness. I think that musical recklessness goes a long way on records. You don't hear enough of it."

Mixing, explained Adams, was very much seen as an engineer's performance, an attitude especially adopted by Lanois: "He'd often sit in the back of the room, shouting encouragements like: 'yeah, come on, louder!', just to get your excitement going and put you on edge. Band members would also sit in on mixes, and do a kind of cheerleader thing. It all induces a nervous energy in you and creates a lot of pressure, and gives the whole thing a performance feel. The reason we work like that is that mixing, like music, is a very personal thing. It's the people that are important, and the machines and the quality of them is very secondary. It's like recording Bono's vocals with an SM58 and loud wedges. The important thing is the way he sings, not whether there's spill or not. It's possible to deal with the latter.

"It's the same with mixing automation. Computers are supposed to be like a clone of what you did, but I feel that they don't always do that 100%. Sometimes a tiny move on a fader can make a big difference, but it won't always come back the same way. Maybe it's just the way you feel at a given time, but it actually illustrates the point. I might sometimes save my very last mix in the computer, just for reference, but generally I get a much greater buzz out of mixing manually, just like the band. So we mix manually."

Recording Techniques

DRUMS: Robbie Adams recorded Larry Mullen's kit with only three or four mics, hardly bothering with details like stereo spread and control: "The most basic setup is a mike for the bass drum, one for the snare and one overhead. The kick mic may be a Neumann U47, placed maybe a foot and a half away. I use a Shure SM57 on the snare, and an SM58 for overheads. When Larry plays a double‑headed bass drum I might also place a Sennheiser 421 at his side. Sometimes I might stick an AKG 451 pencil mic on the hi‑hats. I'll compress the shit out of the overhead mic, just to pick up loads of room. Occasionally I might also use an AKG 414 as an ambient mic, placed high above the kit. A lot of this approach is to do with Flood. He's bored with all this traditional, big stereo nonsense. This way of miking gives you a far more sonically interesting result which can be applied in many different ways. The drums on songs like 'Stay' and 'Babyface' were recorded like this."

GUITAR AND BASS: The Edge used either an AC30 amp or a Randall amp, covered in fake zebra skin. Adams miked the amps with an SM57 close up and an AKG 414 about four feet away. "His guitar amp will be in some sort of booth, or in a separate room, because he plays really loud. He'll hear himself through the monitors. Edge will very often come up with the goods on the first take, so you have to be ready to get it on tape right. The effects tend to be Edge's. He'll fiddle around and get a sound together that he knows will fit the part he's playing, so in the mix it's usually a question of only adding a bit of EQ and reverb." Acoustic guitars were usually overdubbed, using a pickup and DI. For the bass guitar Adams took a DI from the bass as well as the bass amp, and occasionally close miked the bass cabinet — also placed in a separate room, or partitioned off — with a Neumann U47.

VOCALS: Bono's vocals were largely recorded with an SM58 and compressed with a Summit compressor. Adams: "Instead of using the Summit, what we did on several of the tracks on Achtung Baby was to record his vocals on tape with Dolby SR and play it back without Dolby SR. It tightens up the vocal sound and gives it more brightness and presence. It makes his voice sit really nicely in the mix and easier to balance."

Zooropa Tracks

  • NUMB
    'Numb' is one of the stranger and more experimental tracks on Zooropa, with The Edge's deadpan vocal addressing the numbness that results from an overdose of media information, and Bono singing a falsetto background vocal. Adams: "The song is about a monotone vocal with a cacophony of music and noises in the background. It's based on a track originally recorded during the Achtung Baby sessions in Berlin, called 'Down All The Days'. That was quite a ballady song and in the end it was decided that it didn't fit on Achtung Baby. Then Edge had this vocal idea that took the song in a different direction."

Flood made a stereo submix of the Berlin version that contained guitar, bass, bass pedals and drums. "Brian Eno worked on the song in Windmill Lane, adding maybe six or seven tracks of keyboards to the submix, mainly DX7 strings and samples, plus percussion — including arabic voices and congas. The idea of his overdubs was to make up music out of non‑musical noises, like loops of pieces of dialogue and video samples. Edge's voice was recorded in a studio in Dublin called Westland, where we went for one day. Edge was kind of mumbling and listening to the track very loudly via the monitors, so I had to ease off on the Urei 1176 compressor in order not to pick up too much spill. I also had to do some subtle gating, to turn the level down when he wasn't singing. Bono and Larry both did some backing vocals, and there was the sound of a rewinding walkman that we recorded by accident and that we looped. It's a signature sound throughout, you can clearly hear it at the end when the song fades in and out.

"The total number of tracks was maybe 15 or 16, and mixing was very straightforward. Edge and I mixed it in Westland straight after the vocal overdub. I mainly used an AMS RMX16 with a nice, natural ambience setting. There's a tiny little bit of reverb on Edge's vocal, but quite a lot on Bono's, because he's singing with a falsetto soul voice that likes to swim. Larry did two vocals, in falsetto and normal voice, and I used a doubling effect on the Eventide H3000 harmonizer on him."

    "From the beginning, the idea was to get Johnny Cash to sing on this song. The band had been really excited about working with people they've always admired. Bono's song with Frank Sinatra is another example of that. Johnny Cash happened to be playing a gig in Dublin and they asked him to come round and sing the lyrics. He did this, then went away again, the band changed the lyrics and he came back to sing them again. In the end we comped these vocals together. The backing track sounds pretty bizarre, with all sorts of tacky, cheesy sounds. Edge likes to describe it as 'the Holiday Inn band from hell.'

"The track started with an extremely simple rhythm on a Yamaha drum machine, the kick drum just going in eights. Then Edge played a very weird keyboard bass over the top on an SY77, very much like an electronic version of German oompah music. That's where the psycho Holiday Inn band idea started to take shape. The keyboard was recorded in the Mac sequencer, and later went to tape. Of all the songs, this was the only one that started off computer‑based, and it was very much an overdub song. After this, Edge overdubbed a guitar, Brian added some organ‑type sounds and Edge did some great backing vocals. Finally, there was an acoustic guitar by Bono in the middle eight, some looped stereo drums by Larry and a vocal track each for Cash and Bono.

"Again, there were maybe only 16 tracks in total. Everything, including the mix, was done at The Factory, on the little Soundcraft 6000 desk. I'd done a monitor mix one weekend and the band really liked it and asked me to repeat it with a few minor changes. It was very simple, mainly just a bit of AMS reverb on the vocals."